FZR600 FAQ's


Yamaha FZR600 Frequently Asked Questions

Last Revised Thursday, July 17, 2003

This is the 13 year anniversary of the FZR600 and I decided to make a semi-complete list of the most common questions I have heard over the years. This FAQ is really aimed at the spirited riders (who should probably be on the track, but think the road is there track instead, Who me?). If you commute to work everyday on your FZR and don’t really like to push it then you probably should have bought a touring bike (a Seca II maybe?).

The answers provided here are compiled with the help of Eric, Jon, and a few others that routinely haunt (or at least used to) The FZR600 Archives. This information comes from years of personal experience and the experiences of many others. If you have ever seen the FZR400 faq, you are probably saying to yourself "he copied the damn thing!" and you would be fairly accurate (I changed a few words, darn it!) Chris Eklund deserves the credit for the original 400 faq that I used as a template. It was very good in my opinion, so I used the same format. Please report any inaccuracies or new findings to me ASAP.

Click and enjoy!

Common Questions

Why did they stop making the FZR600?

Yamaha finally stopped making the FZR600 in 1999 because it had stopped selling as well and they had to many 600 cc class bikes fighting for the same sales.  Yamaha has settled on the R6 and the YZF600 as their 600cc offerings.  Yamaha has had great success with this bike even though it no longer stacks up against the competition (and even its own YZF600 and R6). The bottom line is that the FZR600 is a great middle weight bike that has more than enough power and flickability for all but the most skilled street riders. The FZR600 no longer fills the racetracks as it once did having been replaced by F3’s, F4's, GSXr600’s, ZX-6’s and Yamaha’s own YZF600 and R6I do. Another desirable trait of the FZR600 is the parts availabilty in almost every salvage yard across the country. The 91-99 models are identical (except maybe tire brands and bodywork colors) which makes fixing crash damage much less expensive.

The FZR600’s steel Deltabox Frame is very rigid for its class and still compares quite well to the newest aluminum frames (although not as light). The motor puts out a respectable 75 horsepower in stock form and can be easily tuned to 85 or more. The brakes on the 91-99 model are four piston per caliper and offer very respectable stopping power, better than anything before it and still comparable to today’s newest four or six piston gadgetry. If anything, the suspension and tires combine to hold the highly capable FZR600 back. With some work to the front forks and rear shock, along with new rubber, the FZR600 can easily keep up with the newest crop of 600’s until the pace really quickens.


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When was the bike first produced?

The FZR600 was first produce in 1989 in response to the Honda F1, which at the time was cleaning up on the racetrack against the aging FZ600. The bike has only had two changes in it’s ten year history. The 91 model switched to four pot front brakes, a bigger (four inch.) rear rim, a Deltabox swingarm and cosmetically switched to a single headlight. Then in 1993 they switched back to the dual headlight setup. Other than those changes, the bike has only had new paint schemes since.


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What did the magazines say about it?

When the FZR600 first came out the magazines all said it was a canyon carver just waiting to ponce on the other feeble offerings available at the time. It dominated the racetracks across the US in 89 and early 90. So after it won the AMA title for 89 Honda decided to release the F2. That was pretty much the end of the FZR’s reign on the track. With the exception of a win by the late Larry Schwartzbach (sp?) on a Vance and Hines tuned FZR, the F2 dominated the next 4 years straight. The FZR600 was delegated to filling the back of the grids on tracks everywhere. Today the magazines all mention the FZR600 as the best bang for the buck bike, but that’s about all.


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Which bikes are in the same class?

Honda: F1 (Hurricane), F2, F3, F4, Hawk (650)

Kawasaki: ZX-6 (A, B, C, D, blah, blah, blah), Ninja 600

Suzuki: GSXr600 (new and old), RF600

Yamaha: SecaII, FZ600, YZF600, R6

Ducati: 748(any color, as long as it’s yellow)


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Is it a good street bike?

I believe it is.  It has good wind protection, good low end torque, and is very narrow with short seat to ground distance.  If anything the FZR600 suffers from low clip-on height which can load the fore arms up quickly, but this is true of most sportbikes. Most people who have one as a street bike are very happy with it.


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How much is too much to pay?

Well running, pristine street examples are going for as much as $3500 (brand new sold for $5499).

A decent street bike can be had for under $2000 if the person is really trying to get rid of it (usually to raise enough money for a R6 or some other new toy). You'll most likely find a slightly beat up model, and these can range from $1500 (dings in the frame, missing bodywork, stock suspension, sucked in valves) to about $3500 (fairly fresh motor, good bodywork, some spares).


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What if I want to race?

Honestly, if you want to do anything other than learn how to ride, you are on the wrong bike. The FZR600 is just not competitive in anything but the most novice classes.


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Why does my bike eat intake valves?

This particular question has been debated a number of times. Yamaha apparently made the intake valves out of a very soft metal. After a couple of seasons of pounding the seats at 12+K, the valves tend to "cup" meaning the edges get worn, then the valve becomes shaped like a tulip.

There are many causes for this, and nearly every 600 rider will replace intake valves at one time or another. One theory for this problem is worn valve springs. The springs lose their tension, and don't snap the valve back into place properly. This allows the valve to contact the seat several times (bouncing back a little bit each time) before it seals instead of just once. It's not uncommon for a race motor to go through a set of intakes once per season. (Incidentally, exhaust valves don't have this problem because combustion helps the valves close.) Correct valve clearance, (note that Yamaha doesn't make valve shims smaller than 120's and if you're down that far, you'll need a valve job anyway!) and frequent adjustment/checks helps avoid this problem.

The most tell tale sign that your valves are out of adjustment is hard starting. Preferably, you won't let the valves get to this point, but if your bike seems slow to wake up in the morning, and all the other "normal" things (no gas, fouled plugs, kill switch on, etc.) check out OK, then you need to check them. Another sign is poor compression in one or more cylinders. The manual has a specific procedure to follow to help isolate the problem.

Replacing the valves on your own can be done, however cutting the valve seats should only be done by a shop equipped to do so. Refer to the manual for removing the valves, but to avoid buying all those special Yamaha tools, use a big C-clamp to compress the valve springs, and a magnet to fish out the retainers. Providing your shop with a bare head, and brand new valves should save you a few bucks in labor.


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Is modern rubber available for the 18" rear wheel?

According to some, this is the weak link on the 600. Even though the 600 came with a wider rim than many 1000's at the time (4.0 inches), and was among the first sport bikes to come with radial rubber mounted, the back wheel is still a very industry non-standard 18x4 inch. There are still several choices for rubber (both bias ply and radials) on the 600.

On the front, it seems that most people opt for the 110/70/17 size to preserve the quick steering nature of the bike. A 120 will fit, but slows things down noticeably. A 140 comes stock on the rear, but a 150 will fit with no problems, and the most popular size to date is a 150/60ZR18.

Brands are very subjective. The most common tires that I have seen are:

Bridgestone: BT56SS in three sizes for the front, stock 110/70ZR17, and the oversize 120/70ZR17 and 120/60ZR17. They also make a 150/60ZR18 for the rear. This is a very good tire with good grip and mileage. They also make a BT58 race front in the 120/70ZR17 size.

Dunlop: K591 Bias Ply tire in the 110/80V17 size and the belted version in the 120/70VB17 size. These aren’t the greatest tires, but they are cheap and will perform for the average rider.

D207 Front in the 120/60ZR17 and 120/70ZR17 size. This is an excellent tire, in my opinion it has the most grip for a street tire (behind the Michelin Pilot and Dunlop D207 GP). This is what I run up front.

Sportmax I Front in the 110/60ZR17 front and 140/60ZR18 rear. This is an average tire will decent grip and good mileage. This is what I use in for the rear.

Metzler: MEZ1 in the 110/70ZR17 and 120/70ZR17 in both race and street compounds. They also make a 150/60ZR18 Rear. I don’t know the first thing about Metzler (except they used to make good hard compound slicks for the FZR) so I won’t comment on these. If I get some info from someone, I will update the Faq.

Michelin makes a Macadam rear, and a race compound front.

Regardless of your tire choice, remember that with such a lightweight/low power bike, you should not be spinning the rear or pushing the front too often. If you are, you need to evaluate how old your tires are, and what your suspension is doing. I normally get at least 2k miles out of a front tire and at least 1.5k out of the rear, and this is all at almost race level miles. If you are an average rider you can expect at least double that figure.


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What kind of horsepower should a 600 make?

On the dyno, my EXUP equipped 600 made 75 HP when I ran it on the Dyno back in 94. Well running Sportbike prepped 600's should make anywhere between 75 and 85 HP. Anything below 70 HP means the bike needs some work.

A 630 big bore kit and some head work can net you upwards of 95 HP, but the truly reliable ones (like mine) are making around 80-85.


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What are the most 600 specific common modifications?

The most common modifications to any motorcycle are usually a pipe, K&N or equal air filter, and brake lines. Rather than go with these typical mods, we're going to offer some pretty 600-specific mods.

The sub-frame is steel, and weighs about 13 pounds. Most racers cut off at least the miscellaneous taillight mounting points and passenger peg mounts. Many racers hack off large chunks of the sub-frame in an effort to save weight. The frame itself weighs in at about 41 pounds and the two down tubes weigh 8 pounds each. You can’t really do much with the frame proper or the down tubes except maybe grind off some of the brackets, but you can do a pretty good jobs on the sub-frame by cutting off the little tubes and some off the back. This should only be done if you don’t care about resale value and are no longer going to carry a passenger. A common trick for the poor FZR rider (the wealthy one’s soon figure out the R6 is a much better bike) is to switch to a FZR400 frame. It weighs in at a much nicer 24 pounds, but u still have the 8 pound down tubes (x2) and the steel sub-frame at 13. Still the 17 pounds is worth the hassle (which isn’t really that much). The swingarm is about 10 pounds and the aluminum 400 swingarm is 9.5, so unless it’s cheap there is not much to gain there.

Rear sets used to be a popular modification but the majority of riders who need extra clearance simply cut off the pegs at or near the last hole (designed for holding on the rubber foot pad). Most riders remove the rubber, and cut here at an angle to offer more ground clearance. The thing to remember with rear sets is that the further back they go, the closer they get to the ground. A good rear set will go at least as far up as back.

Reversing the shift pattern is a simple modification. The wrong way to do it would be to flip the existing linkage over, then grind away the part of the frame to allow the shift rod to have clearance. The right way is to use an FJ11 or 1200 shifter knuckle upside down. This knuckle has enough clearance to do the job. The clip-ons can be safely moved under the triple clamps without running into clearance problems with the fairing, although I don’t recommend this because it loads up your forearms and makes any trip longer than a few miles very uncomfortable.

The steering stops on the lower triple clamps can be drilled and tapped so bolts can be installed to limit steering travel, and avoid crushing the frame in the event of a crash. You can also attach wheel weights or something similar to the edges of the lower triple clamp that comes in contact with the steering stop. This will achieve the same effect.

A steering damper can be fit in front of the steering head with many aftermarket kits. Essentially though, if you have the fork tube clamp, a piece of aluminum bent in a 90 degree angle with two holes drilled in it will do when bolted to one of the front fairing cage mounts.


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How do I keep the #$%*ing airbox on?

Finding a way to keep the airbox on can be a challenge. The airbox is a common complaint among 600 owners since many are street bikes and many more compete in classes that require the air box. It seems that they are hard to get on and come off at the most inopportune times (like when you're just about to pass someone!).

If the nipple at the front of the airbox isn't in the little retainer, you'll never get the leverage you need. If your nipple is gone (heaven forbid!), drill the box, and secure a bolt in the same position with some fuel line around it instead.

If you still have a hard time keeping the box on, you can do a number of things:

  1. Use a big piece of foam under the tank cover to keep it in place.
  2. Drill the air box, and use zip ties to fasten the back end of it down to the gas tank mounts.
  3. Duct tape it, front to back to the gas tank.
  4. Replace your crusty, hard, rubber pieces that fit over the carburetors with new, fresh, rubbery ones.

From Brad Lengel: "I had the same problem. The rubber couplers were kind of deformed where they fit over the carbs. Probably from not being seated good and then over tightening the clamps. I replaced the worst couplers (about $6 a piece) and it seated much better. Just consider replacing the couplers as normal maintenance. I also use a small strap looped over the airbox from the radiator filler bracket to the cross-piece bracket of the fuel tank to make sure it stays in place during races. I also like to replace the Phillips head screws of the clamps with Allen head bolts where ever I can."

One of the biggest things I can tell you is never leave your airbox of the bike for long periods of time.  The little rubber pieces immediately start shrinking the second you take it off and if you are like me and leave the bike apart for a month the airbox with be a pain in the butt to get back on!


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Can I improve the braking?

Sure you can, but the better question is, do you need to? The stock brakes on the 600 are more than enough to stand the bike on it's nose and are of the same design as the brakes found on the new R6 (although the R6’s brakes look prettier). If you like the look of the R6/R1 brakes they should be a bolt on replacement.  I have seen them installed on a YZF600 (95') and the brakes on that bike are identical to the 91-99 FZR600 (I know I am using my original brakes on my YZF frontend)

Steel or kevlar lines are a must for the track, and help on the street as well since they don't expand under hard braking. It's one of the cheapest mods to any bike, and improves performance noticeably. Combined with aftermarket pads like EBC's Greens, Galfer's or Ferodo's, the difference is dramatic. Remember when you change pads that the olds pads faded gradually and the new ones are going to bite a lot faster and a lot harder initially.  You definately do not want to grab a handful of brakes right after changing them. You might end up on your head.

Another common improvement is to replace the stock master cylinder with a remote reservoir model. The one I used is from the 92 ZX-7 (I wanted a black lever). It is made by Nissin and is a common type used on several bikes (ZX-7, CBR900, YZF600, GSXr-750). All you have to do is decide which one you think looks better. They all offer the same performance and an adjustable brake lever. On the stock top triple clamp you will have to drill a small hole to mount the reservoir but it is easy to do with a small drill bit since the aluminum top clamp is soft.

You can "float" your stock rotors if they're slightly warped, or if you just like the jingle bells sound they make. Use the ball end of a brake lever and a socket a little bigger than the back end of the buttons on the rotor. Put the ball end on one side, the socket on the other, and squeeze the whole contraption in a vice. Repeat equally with all the buttons, and your rotors will dangle in place. Nolan Ballew suggested this method, and Tony Pagliaroli tested it for 6 weekends at Loudon without incident. Aftermarket rotors are also available from EBC, Ferodo, and Braking for less than what it costs to replace the stock rotors. The EBC's are the most popular choice, the cheapest, and come with "bolt on" convenience, whereas the others need to be attached to the stock carriers.


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Do I need ride height adjustability?

No. Not unless you've switched to a 17" rear wheel, and several racers have also done this mod without changing the rear ride height. Ride height adjustment is a nice thing to have if you know what implications the changes you are making have, but it is not absolutely necessary.

As an alternative to buying a new shock with ride height adjustment, there's a company that makes custom shock linkages (dog bones) for the 600 which, when bolted on to a bike with a 17" rear wheel, bring the ride height back to stock specs. Ride height can also be added to most shocks at an additional cost during rebuild. Most aftermarket shocks now come with ride height, and this should be taken into consideration when pricing your new $600 toy.


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What do I do if I need more power?

Everybody could use a few more ponies at the rear wheel, and one of the easiest ways is by letting the motor breath better. The first change I would recommend is to get a good pipe and jet kit. Both Factory and Dynojet make jet kits for the FZR600, or you can just go buy a set of 110 main jets and do it your-self. Pipes I personally recommend are the V&H Supersport (cheap) and the SS2r (not so cheap). I recommend the full system over a slip on especially if you have the Exup system on your bike. Many people are going to argue that point, but I have seen the dyno charts before and after and the bike without the Exup puts out a smoother power band and more top end horsepower at the expense of midrange. I don’t ride around in the midrange very often so I’ll take the HP.

That is the easy way to make 5-7 HP without much effort. Every pony after that will take more work as well as more money. You can time the cams with slotted sprockets, add an ignition advancer, install a big bore kit, hotter cams, hotter coils, a Powerpak, and of course cutting off any unneeded weight. I can’t stress weight loss enough (although I definitely don’t lead by example with my fat ass). Every 7-10 pounds you lose (depending upon who you ask) is worth 1 horsepower. If you can shave 50 pounds off yourself and your bike it is effectively the same as jetting and piping your bike. Best of all it is free! With the exception of a few riders out there, you don’t see to many champions at 6’2" 220lbs. This is definitely a sport where the little guy has an advantage (although Curtis Adams is damn fast at 6’5"? and about 180ish). This translates to the street as well. A 400 pound FZR is going to outperform an otherwise equal 450 pound FZR every day of the week. It is easier on tires, chain, sprockets, motor, and everything else.


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What's the EXUP thing?

The EXUP valve is a servo motor controlled exhaust valve that increases back pressure to your motor under certain circumstances, increasing torque while reducing emissions. This option was only present on the California model FZR600's, and was promptly tossed at the race track.

Jay McDaniel has a great copy of a magazine article discussing the EXUP valve on his site. Jay is also a real helpful guy and he knows a little about the 600 in a 400 frame swap. Jay can be a little safety minded at times, but hey, he’ll probably out live us all and he goes fairly quick at the track where it counts.


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What are these mixture screws and what do they do?

The mixture screws adjust the air to fuel ratio in each carb (one screw per carb). This allows you to fine tune you bike. Unfortunately the EPA has decided that for the sake of the environment, the screws should be preset at the factory and covered with brass caps so that the user cannot make these adjustments. What this means to you is that you have to drill these caps out to make adjustments to the mixture screws.


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What are my bodywork options?

Several companies including Airtech, Sharkskinz, Beasley, Mototech and National Fiberglass make replacement fairings for the 600. Every report lists Sharkskinz as the best (albeit one of the most expensive) as far as quality and crash-ability.

Among the most popular variances in fitting different bodywork on the 600 is a TZ250 tail section. A 1990 TZ tail fits as long as you cut out the seat pan, drill a slot in the back for your stock seat, and use the tabs originally designed for the "nipples" of the stock rear seat panels for mounting. You can also mount the Airtech Aerotail (what I have now) and  YZF750's tails have been mounted with minimal effort as well.


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Can I run total loss on the bike?

Running total loss is a relatively easy way to get a quicker revving motor, but this is only for race bikes since a battery won't last more than 2 hours running this way.

Essentially, you remove the flywheel on the left side of the motor. Remove the magnets off the inside (they are glued in there, and require a bit of prying to get out), then remove the generator that's behind the flywheel. You need to retain the ignition pickup, and put the flywheel back in place, otherwise, there's nothing to drive the spark.

It's up to you if you want to have your machinist put the flywheel in a lathe to turn it down some, and whether you want to remove the starter as well. If you remove the starter, you'll need to fabricate a plate to seal off the hole it leaves, and you'll also be able to get rid of the starter gears on the right side of the motor as well.

If done properly, you'll end up with a much more rev happy motor, but the headache of push starting the bike all the time, and blipping the throttle at the starting line, praying that the bike doesn't stall!


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Can I convert to 520 chain?

Converting to a 520 chain is fairly easy and only can be done safely at home.  You need to replace both front and rear sprockets as well as the chain itself.  There are several companies that make sprockets and chains for the FZR in 520 size but the most common one is a kit by RK.  The kit limits you to 14/45 or 15/45 ratios but you can buy the sprockets seperately if you need a different ratio.  Just remember that not all 520 chain is built equal.  Some 520 chain is designed for bikes running less the 400cc (or about 60HP).  You can still use it but it will wear much faster and could break under hard stress.  Most companies list the CC rating of their chain.  Do not let a salesman at the counter or over the phone sell you any old chain.  Do the research and find the right chain and sprockets for you.  Some of the different places you can go are listed below. The advantage of the 520 is a major weight savings (sometimes as much as 3 lbs.) and a small amount of additional clearance for the tire (in case you are shoving a bigger tire/rim on the back). Afam Drive Systems

Regina Chain

RK Chain

Tsubaki Chain

DID Chain


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Can I improve the front end?

Without swapping for a different front end, there are a bunch of things you can do to the front end (which is totally non-adjustable) to improve it's feel (and still stay legal for Super Sport/Sport Bike, Production, etc.).

First, you can opt for different springs (Race Tech's straight rate springs seem to work the best, but others have had success with Progressive Suspension's progressive springs too). Just follow the application chart, and size up the springs according to your weight (racers, don't forget to include the extra baggage of your helmet and leathers).

Whether you change the springs or not, setting the sag properly is essential to a well handling bike. Race Tech has an article on setting sag that is pretty comprehensive. Really, all you need to do is make spacers out of the appropriate diameter PVC tubing, and insert them into your forks in place of the stock spacers. You adjust the sag by the length of this tubing. The Yamaha race kit, as well as one aftermarket manufacturer, had fork tube caps that allowed you to adjust the preload without changing spacers, but they are no longer available.

Another, more subjective move is to move the fork tubes up in the triple clamps. This will effectively decrease the trail, and make the bike steer even quicker, while putting more weight on the front end. Normally, you shouldn't move them up more than 15mm, but some pilots have gone as far as 30mm and still run good lap times.

The newest mod has been the installation of Race Tech's Cartridge Emulators. Essentially, these are little valves that sit on top of your forks damping rods, and let you adjust the compression damping. The installation is fairly straightforward on the 400, but setup can be tough depending on your skill level. Concerning disassembly, use an air or electric impact wrench to remove the allen bolt holding the lower and upper slider together. If you try to remove it by hand, the inner damping rod will spin. The impact will usually spin it out quickly enough to avoid this problem. Yamaha makes a special tool to reach in and hold the damper rod, but the tool is not cheap. If you having a problem pulling the fork tubes apart because the damper rods spins then here is a tip from Jim Brewer:

"I used a 20" long bolt with a hex head that just fits the top of the damper tube (15/16" from flat to flat). I double netted the other end of the bolt so I could hold it with an adjustable wrench. It cost me about $2.

The base setup in the emulator manual seems a little soft for the race track, so you might want to give it a couple of twists. Most important here is to remember what you've done by keeping notes so you can always fall back to something that's worked already. Once set up properly, the emulators make a huge difference in the feel of the front end, and your lap times should drop with your new found confidence. The emulators retail for about $100.

Here's a couple of base settings from other 400 racers: Shawn Cash: "I weigh 165 lbs. sans gear. I put .85 kg/m RACE-TECH springs, gold valve emulators, and use 10wt oil set at 92mm from the top (factory spec) measured with the emulators in. I removed the factory spacer (the RACE-TECH springs are shorter) and cut a 93mm spacer which gave me 28mm sag. I can put my front wheel anywhere, and it will stick with no complaints. I wish I could say the same about the rear.....

Two bits of advice: Don't skimp on tires, get the best. Get a length of 3/4" (I think) PVC pipe. Initially cut your spacers out of this. Then when you find the length that works best for you, cut the aluminum one that RACE-TECH supplies with the springs to the same length."

From Ken Hsu: "I installed the .85 Race-Tech springs (picked from the same chart you probably are looking at) and I am around 140lbs not including gear. They felt fine for what my opinion's worth and the allowed compression travel seemed to make sense also at 80mm plus 25mm sag."

If you decide to swap front ends, there are many ways to go. Some swaps may bolt in, some may require changing the steering stem, others may require new triple clamps. Remember changing front ends may affect the handling characteristics of your 600 for better or worse. It's important to understand the difference between the original fork offset and the offset for the front end you want to use. Take measurements, ask questions, see what others have done.

From Chris Eklund: "GSXR front ends are rather popular as they offer external compression, rebound, and pre-load adjustments. The upside-down (USD) forks are rather heavy, and will noticeably slow steering and increase unsprung weight. The conventional forks are good solution and will probably cost less than the newer USD forks. Word from Jim Lindemann is that the forks of choice are the '88-92 GSXR750 forks as they are better quality (Showa) and close in their damping rates then the GSXR1100's Kayaba forks.

FZR1000 front ends (87-90) are a bolt on if you replace the entire front end (triples, tubes, wheel, rotors, etc.) The advantage is a fairly easy swap giving you larger fork tubes (87-88 41mm, 89-90 43mm vs. 38mm stock), preload adjustment, wider front rim (3.50"vs. 3.00"), and bigger brakes. You still don't gain external rebound and compression adjustment, you increase the unsprung weight, and reciprocating mass. A better swap would be from a motor cycle of similar dimensions."

95-96 YZF600 front ends are a direct bolt on as well and offer much better performance with almost identical weight. This is the front end I have currently. The 96 front had more adjustability (cartridge) but either are much better than the standard forks.  This is very straight forward swap but you need the whole YZF frontend (brakes are the same though).


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Can I improve the rear end?

Adding a quality aftermarket rear shock is a great, albeit expensive way to improve the handling of your bike. In fact, if you've never ridden anything that has decent suspension components on it, you'll be amazed at the difference.

Unfortunately, aftermarket shocks are expensive. Works Performance offers a preload adjustable replacement for around $400. They will build the shock to have damping rates appropriate to your weight and riding style.

Moving up the ladder, Fox offers the Twin Clicker, with adjustments for preload, compression and rebound damping and ride height at a cost of nearly $550. This may be the most popular road racing shock for the 600.

Further up the ladder is the Ohlins shock, with features exactly like the Fox, but for about $200 more. Top pros use Ohlins parts, but most privateers shy away from the price.

What all these options offer is the ability to rebuild them once they've lost they're damping qualities. Rebuilds generally run from $100 to $200. For comparison, a stock shock (completely non-rebuildable incidentally) is over $600 from Yamaha. Used shocks come available from time to time in the $200-$350 range. Be prepared to have the shock rebuilt (oil change and nitrogen recharge at least) especially if it's leaking, old, or the previous owner has no idea if it was ever rebuilt or serviced.

The 400 swingarm is also a direct bolt on, but is made of aluminum and is a little lighter than either the regular box section steel swingarm, or the 1991-99 Deltabox swingarm. It is about ½" shorter and will make the bike wheelie easier and shorten the wheel base. It should also make the bike steer a bit quicker. It may affect high speed stability (110 mph+) but I have not noticed any serious problems on mine at those speeds.


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What parts are interchangeable with the FZR400

The following parts will interchange between a 400 and a 600:

  • rear wheels (if you use the caliper hanger that goes with the wheel)
  • front wheels (as long as the rotors/calipers go with their matching forks)
  • complete front ends (triple clamps are the same)
  • motors (with the change of a few things - see 600 motor swap)
  • handle bars and levers
  • gas tanks (the 600 has a slightly higher filler neck, but fits every where else)
  • switch gear and throttle (cables differ at carb)
  • foot pegs and levers
  • clutch cables
  • swing arms
  • rear shock and all linkages
  • carbs (may need jetting change)
  • front brake calipers (only applies to '88-89 400's and pre 4-piston 600's)
  • rear brake calipers (all)
  • front and rear axles
  • rear gas tank brackets
  • regulator (Sloan's says the part number is 1 digit off, but this has been tested in racing circles)
  • radiator fans
  • radiator caps, (Quoted from an anonymous source - If the price of a new Yamaha radiator cap makes you choke, go to your local auto parts store and buy one for an '89 Honda Accord. It's the same.)
  • thermostats
  • gas caps (Note, the filler neck on the 600 tank is taller)
  • ignition switches
  • sprocket covers
  • starter clutch covers
  • starter relays
  • cam chain tensioner
  • turn signals


As far as swapping parts between models, the '89 and '90 models are identical. The only differences to the '91 model is paint, 4-piston calipers, rotors with a different offset (but same diameter), a bigger 4 inch rear rim, and the Deltabox swing arm. The 91-92 models also have a different upper fairing and a single headlight.


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My bike is hard to start all of a sudden, why?

You can check the Valves portion of the FAQ for more information, but generally, if all the normal things check out, you've probably got worn intake valves. Follow these steps for determining the cause of hard starting:

  1. Make sure your battery is fully charged.
  2. Ensure you have enough gas, and that the petcock is not off.
  3. Make sure the kill switch is in the on position, and when you click the ignition to start it, the fuel pump is activated.
  4. Pull a spark plug and make sure it's not fouled.
  5. Make sure your carbs are clean and not clogged.
  6. If the motor is turning at this point, yet still not starting, you probably have a valve problem, and they at least need adjustment.

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My bike breaks up in high rev situations, why?

The FZR600 requires a fully charged battery to run properly. If your battery is running down a bit, you may get high rev stumbles that feel like the bike is running out of gas. The simple fix is to either install a new battery, or charge the one you have.

But while we're on the topic of battery charging, the most likely cause of your battery becoming insufficient is overcharging. This is a common problem on the 600, and is usually caused by a faulty regulator. Keeping the regulator cool can go a long way to helping keep the battery alive.

One sure sign that your battery is overcharging is the loss of paint/clear-coat off of various parts of your bike from battery acid being spit out of your battery overflow tube. Again, since this is a common problem on the 600, it's not unusual to see swingarms spotted with polished parts from where the battery acid made contact.


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Can I change the rear wheel to a 17 incher?

Sure you can, but note that the only real advantage to installing a 17" wheel is to take advantage of the latest generation of racing rubber. This info is geared towards the 400, but the 600 uses the same dimension wheel and spacers.

Contributed by Chris Eklund:

"I currently run Honda CBR600F2 (17x4.50) and F3 (17x5.00) rear wheels on my race bike. My street project FZR600 street fighter will be using a GSXR (17x4.50) rear wheel.

To use the F2/F3 wheels, this is what I had done. Any competent machinist could do this, or they may have a better idea. This is how my guy did it:

First thing is I took Lester a stock wheel complete with spacers, axle, cush drive, brake arm, etc., a spare 400 box-section swing arm and a complete F2 rear wheel. This way he could measure everything from the stock wheel.

He removed the sprocket studs from the cush drive. (Note: Honda uses locking agent that is _tough_! Be sure to heat the studs when you pull them.) The outer bearing surface was machined down. This eliminated the rubber bearing seal, so a single sided waterproof sealed bearing of the Honda OEM size was used. The sprocket surface was also machined to move the sprocket inward. (Note: If you have '90 Deltabox swing arm, the studs need to be shortened and the nuts ground down to clear the swing arm. I'm not sure if this step is necessary on a '88-89 box section arm since they have more clearance. I ground about 2-3mm off the nuts, which was basically the locking portion of it, so I now have mine safety wired. Makes rear sprocket changes time consuming, but it won't come off and I usually know what gearing I'm going to run at what track beforehand. If you can get some low profile lock nuts, that would work well. Ideally, I'd have a spare cush drive modified.

New wheel spacers were machined from steel and have a sleeve for adapting the small FZR axle to the larger F2 bearing. This way the spacers are captive and won't fall out. (Note: Another option is to use the F2/F3 axle. The stock F2 axle will fit in the '90 swing arm. All you'd have to do is drill out the holes in the v-blocks. The F2/F3 axle is about 2mm larger and hollow.

For the brake, Honda uses a floating caliper mounting system as opposed to the Yamaha's fixed caliper. I use a Hurricane 2-piston caliper, but plan to use a F2 single piston one soon. A CR125/250/500 rear caliper might be another option. I've seen a CR125 caliper used on an F2 rim on Simon Forder's EX500.

The large hub on the F2/F3 wheels won't allow an opposed piston caliper go all the way over the rotor. The GSXR wheel can be used with the FZR600 hanger and stock 400/600 caliper or you could get the GSXR rotor turned down the same diameter as the stock 400 rotor. I think the F2/F3 wheels are lighter than the GSXR, but I can't guarantee that.

The GSXR wheel requires the same type of work, but is simpler for a few reasons. The cush drive uses bolts to secure the sprocket so when you remove the sprocket, the bolts fall out, unlike the studs on the Honda. These bolts are of a smaller diameter than the Honda studs and already uses low profile locking nuts. And as I mentioned above, the brake situation is easier to deal with. Plus it's a three-spoke wheel and matches the stock front wheel. GSXR rims may be getting hard to find since they were only used on '88-89 GSXR750's and '89 GSXR1100's.

Here are GSXR dimensions and directions from Nolan Ballew:

  1. "Remove .345 from sprocket carrier where sprocket sits.
  2. Remove .305 from sprocket carrier where stock bearing seal sits.
  3. Replace bearing with sealed bearing type but same size.
  4. On sprocket side use stock spacer plus 25mm O.D. 17mm I.D. by 1.73 inch spacer that slips into carrier.
  5. Use stock brake arm and .510 spacer with 17mm I.D./ O.D. of this spacer is non critical. this spacer goes between brake arm and wheel bearing like stock one.
  6. The stock Suzuki disc can be cut down to the same O.D. and width as 400. The O.D. with have cut thru holes or you can make a disc. The stock disc cannot be adapted.
  7. Stock caliper needs bottom left surface filed down about .025 to provide clearance for larger hub of GSX-R-r wheel.
  8. A 600fzr caliper bracket can be used with the stock Suzuki disc but then you cannot easily switch from a stock wheel to the Suzuki wheel if you have 18 inch rains on stock wheels (Bridgestone).

I don't have a number for the 600 caliper bracket but once the other side is done the measurement should not be too difficult."

TZ250 rims have been used and apparently only require new spacers being made (according to Motorcyclist article 9/90.) TZ rims wider than 5.00 may require moving the chain out to clear the tire.

As recommended by Sam Flemming of the Army of Darkness, Wheels without cush drives should be avoided (i.e. older Performance Machine wheels.) The shock of each power pulse will take it's toll on the 400's not too terribly tough transmission and clutch.


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Can I make my brake rotors full floating?

This mod is not for the weak of heart, but can be done safely by following these instructions:

You can "float" your stock rotors if they're slightly warped, or if you just like the jingle bells sound they make. Use the ball end of a brake lever and a socket a little bigger than the back end of the buttons on the rotor. Put the ball end on one side, the socket on the other, and squeeze the whole contraption in a vice. Repeat equally with all the buttons, and your rotors will dangle in place. Nolan Ballew suggested this method, and Tony Pagliaroli tested it for 6 weekends at Loudon without incident.

More front brake mods are listed in Can I improve the brakes?


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How do I remove the *&$#ing flywheel?

We could tell you, but we'd have to kill you! This is a common question, and at $275 a pop, you certainly don't want to destroy the thing!

If you do it the right way, you'll buy the $10 flywheel removal tool from your local shop. Essentially, this is a big threaded bolt that screws into the flywheel, and against the crankshaft. Experience tells us that simply screwing it in there with an impact wrench doesn't always do the job, and can strip the puller inside the flywheel, causing all sorts of headaches. Ironically, the rear axle will also serve this purpose, and is recommended by many 400 listers. Try it at your own risk.

The proper procedure is to tighten the puller down as snug as possible, then smack it with a hammer right in the center. Tighten it down again, as snugly as possibly, and smack it again. Repeat this process until the flywheel pops off.

If you can't get it off within a half an hour, bite the bullet before you do some real damage and go to a shop. Let them screw it up so you don't have to pay for a new flywheel!

Putting it back on is a different story... From Dave Sweeney:

Since it's already off(heh, heh) make sure the mating surfaces of the flywheel and crank are clean, clean, clean!! This includes the woodruff key and the corresponding slot on the crank. No burrs or gunk on the mating surfaces at ALL. Use a little 600 on the mating surfaces if you need to. Rotate the crank so the key slot is up. Get the bolt(also really clean) and all ready for assembly.

OK, now for the unbelieveable part. Get out your trusty RED locktite and coat the mating surfaces thoroughly. This keeps it all together, and keeps the flywheel from welding itself to the crank(the reason you couldn't get it off in the first place). Put the key in the slot, slap it together, put in the bolt and torque it down to 58 ft-lbs. Viola! Next time the flywheel needs to come off, it will.

Whatever you do, DO NOT USE ANTISEIZE! The taper of the crank/flywheel is to hold the flywheel on, the bolt keeps the mess from vibrating loose. Better to put it together dry than with antiseize.


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What parts can be polished?

Everything can be polished, but only the aluminum parts will stay that way. You can polish the top triple clamp, foot guards, footpegs, brake and clutch levers, all case covers, gas cap, the ring around it and the wheels. Take the CAN I POLISH IT TEST! Put a magnet on any of the metal parts, if it doesn't stick you can polish it.


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Can I put a bigger tire in the rear?

It's suggested you go up only one size. Any bigger on the stock rim will be squeezed, if not rubbing on the chain or brake arm. You can get almost any swing-arm to fit as long as you're not afraid of doing some machining yourself or have a shop that can do it. Easiest choise is to put a yzf swing-arm and rear rim. The yzf swing-arm/rim requires the least amount of work, its almost a straight bolt on mod. The rim that comes with it, (or should anyway) is a nice wide rim that will fit any modern tire. I would stay away from swingarms off larger size bikes (ie: 750, 900, 1000cc). These bikes generally have much beefier swingarms to withstand the extra horsepower, and because of this they usually weigh more (not a good thing). If you are going to switch, pick a bike that is much closer in size (YZF600, CBR, HAWK, ZX6). You have to be real careful with the measurements or you could end up with a 60 inch wheel base and don't forget the differences in shock linkage locations etc , your bike may look cool but handle like shit.

You can use a wider rim on your FZR 600 with the stock swingarm, look for an F2, Bandit 400, older GSXR 750 91 or older, or TZR / TZ 250 rim , depending on the rim depends on how much machining needs to be done and or fabrication , the TZR rim for example is almost a drop in , just use the TZR axel , widen the axel bolt holes all the way thru , file the slots in the swing arm slightly bigger and tweek the brake torque arm out slightly , you can fit a 160 on there nicely , could fit a 170 but you have to look at sidewall size as a consideration to get it to fit .... Another option would be a Hawk 650 single sided swing arm and rim ..... How many of you have ridden converted bikes ? And pushed both to the limit ? A properly set up 18 " 140 width combo will out run / out corner a 17 inch 160 width tire anyday unless the bike is properly set up and you can seriously push the bike beyond the limits where you are basically rear wheel steering the bike on the track or pavement. Save the money you would spend on doing the conversion and by a set of Race Tech Emulators and springs or maybe a different rear shock and get it set up correctly.


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Lights and wattage

The stock wires are good to about 12 amps, which on a 12v system is about 144 watts. That means you can run 72 watts a side (or less). So if you run a 55 watt on one side you should be good to about 90 on the other. These are fairly conservative estimates.


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What's the best brake pads?

The Yamaha Stock Pads are the best! SBS Pads are the best! EBC Pads are the best! Confused yet? Basically pads are not the same. They all have a different degree of three qualities. 1 Braking power, 2 Initial bite, 3 Longevity. Braking power is just how powerful the brakes are, Initial bite is how fast that power comes on, and longevity is how long they last. Your preference will determine which pads you will like. The only way you can find the right pads is to try each kind and figure out what you like. It really is a personal thing (at least in my humble opinion).


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What's a 520 conversion?

It is when you take you stock 530 size sprockets and chain and trade them for 520 size. This gets you a lighter chain and sprockets (not much on the sprockets, but alot on the chain). It also gives you more clearance between the chain and the back wheel (this does effect performance unless you trying to shove a 160+ size tire back there). Less weight in the chain will give you faster acceleration and less drive line lash (make the bike a bit more stable under power). It's what the Gp bikes use, so it's plenty strong and will last just as long as the 530 if not longer.....


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What's back cutting the gears?

Back cutting the gears is a modification done to your shift dogs. Each of your transmission gears have three teeth on them that interlock with three other teeth on the ajoining gear in order to engage a gear. These teeth are called the shift dogs. Back cutting is when they take the otherwise straight teeth and cut a backwards slant on them. The matching teeth also have this slant cut in them so that the gears now interlock. This prevents the transmission from jumping out of gear on halfassed shifts like power-shifting. Instead the transmission locks together tighter. Hence no skipped gears means longer transmission life and your shifts are MUCH smoother.


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What type of bulbs are in the guages?

There are two different bulb sizes 3 of one type(12volt 1.7 W) and 1 of a smaller size(bottom of the speedo).

Try a #161 from your local parts store for the three larger bulbs. It is a T-3 1/4 wedge base, 0.19 amps, 2.28 watts, and 1 CP. These might be slighly brighter than the originals. The Stanley bulbs were 12V 1.7W.

These are worth a try as they were 3 for $2.40 at the parts store and from Yamaha they are about $5.30 each.


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