MadSi RacingMadSi Racing — the FZR400 site

Maintenance / Technical Articles

Here will be listed as many technical articles as I can possibly muster together. Some will be specific to the 2TK while others (probably the majority) will be applicable to other models, even other makes of bike.

2TK specifications are on their own page which can be found here

New Magazine articles related to the FZR400 can be found here

Much of the information here has been taken from searches on the internet and the Yahoo FZR400 mailing list — a community sadly lost when Yahoo Groups shut down, but its collected wisdom lives on in these pages.

Should you have anything to add, please get in touch.

Wheels

The standard wheel fitment for the 2TK is 17" front & 18" rear. It's getting harder and harder to locate sticky 18" rubber but obviously a lot lot easier to obtain the latest sticky 17" rubber.

Many people replace the 18" rear with a 17" from another model. To date, i've discovered the following may be suitable - check before committing yourself:

From the Yahoo FZR mailing list

Any of those will take some modifications - and someone who's done those (not me) can give you more info on how to get them fitted up.

Also, one of the guys I race against replaced the whole rear swingarm and
wheel with a YZF600. Apparently that required a small amount of milling of the swingarm where the pivot is, like 1/4 inch on each side or something.

A Suzuki Bandit wheel (91-93 GSF400 Bandit), if you can find one, almost bolts up. Same bearings so you can use the same axle. You just need custom spacers and to cut the Suzuki brake rotor down about 1/4" to fit the standard caliper, and space the caliper in a bit. In addition to the GSF400 bearings, you can use the internal spacer, the cush to wheel spacer, and of course you need a GSF400 cush as well. Just need the outer spacers and the brake mod's as below.

It's the same 4" width as the original wheel, so if you are racing in a class that requires you to keep the same width if you are updating to a 17" wheel it works well.

Another user with a Ducati wheel:

Ok I did it. My experiment with the Ducati wheel has worked. I am so stoked because I this was an experiment that will solve a lot of problems for many people.

I found out a little while back while going through the used parts dealer that the front gear drive from a ducati 916/748/996 is the same ratio as the FZR's/YZF's. It is also the same diameter as the axle for my GSXR front end. (which I think is the same diameter as the axle for the R6 front end too!!!!!!) Interesting note, the bolt diameter pattern for the front disks on the Ducati wheel is the same as for the inner bolt pattern of the FZR600 disks, which are the same
size as the disks for the R6 front end. So there are options for front end with a speedo like stock. R6 or GSXR 750!!!!!

Any ways after much banging my head against a wall I got my GSXR750 front end completely mounted up correctly. The lock on the front for the frame tube even works just like stock too. It is like stock from factory. I had to space the brakes out in order to get the Ducati wheel to match up perfectly but it works great and handles like a dream. It takes a lot of work so this is not for the non
mechanically inclined.

I also took a different route on the airbox issue for the YZF600r motor. I used the air box for a 95 YZF600. I had to modify it a lot but it is done now. I left some pics in the pictures section of the mods that I did of that.

But just to run down a list of what I have done to the bike. 1990 FZR400 with a 98 YZF600r motor. 98 GSXR 750 front end with ducati wheel and speedo. steel braked brakes. 89 GSXR 750 17in rear wheel, YZF750 tail section and seats, R1 tail light, Carbon fiber tank cap, 92 FZR600 upper with headlight from a 94FZR400rr jap spec bike. This is a really cool piece that has 2 projector beams inside that light. Over Over racing full racing exhaust. (imported from
Japan not sold in the USA.) fully jetted to match. Frame slides, rear lift points for stand, safety wired NRC case covers, There is more but I can think of it. Thanks to all that have put information on this site. I would not have been able to complete the bike without it, or even know where to start either.
Later
Noah
in Denver

Tyres

BT-010's

BT-56ss

GPR70SP

GPR80

BT090

Suspension

To stiffen up the front end a little, change the oil and replace with 15wt to a level of 100mm (no springs in when measuring). If still not stiff enough, reduce to 90mm.

Fork Seals

Steering Head Bearings

See http://autos.groups.yahoo.com/group/FZR400/message/29195

Just basically tighten it a lot to settle it in, then loosen, then tighten by hand/feel until you get rid of the excess play, but without excess drag. It helps to have the fork tubes in so that you can have a lever to wiggle the steering head with as you do this.

It is handy to have the right kind of spanner to turn those stupid nuts with, though. Otherwise it's the screwdriver and hammer method :-). I bought a cheapo set from Harbor freight that had big ones for the preload adjuster on the shock, and small ones for the steering head nuts.

I just did this last week. Tighten the adjuster nut with spanner wrench (or
hammer and screwdriver) a little bit at a time, and each time check for play
between the steering stem and steering head. I could actually see the lower
triple clamp move relative to the frame by pulling every which way on the
front wheel.

Another thread:

I discovered that excess drag can occur AFTER tightening the steering stem
nut, which sits on top of the upper triple clamp. My manual says it requires 80 ft lbs, and after that is tight, it makes a difference.

And even when the bars seem to have no drag on them in the garage, the road test says something different.

I test rode my bike and found out that if the steering head bearings are too
tight, it's like having a steering damper. I can't really ride the bike well with no hands. As I make minute adjustments with my body position, the bars will get stuck pointed left or right. I can't ride straight! It's hard to balance, too, wanting to fall over one way, then the other.

It may sound like a queer test, but even when riding with all my fingers on the bars, I can feel the bike wanting to go left or right due to "sticktion". After loosening the bearings a little (maybe 1/8th turn, or 1/16th turn) I could again ride in a straight line, with or without hands.

Curt

Brakes

Any of the 90s GSXR, ZXR Nissin master cylinders with remote reservoir work great. All you need to fabricate is a simple bracket to mount the reservoir, usually just a flat piece of aluminum with two holes, bent to level the reservoir.

CBR 400. Seems to be a touch more sensitive than the original. Aprilia RS250 has a different thread size but bore size is the same. I believe the VFR400 and the RVF400's also work.

Final drive

The size of the front sprocket nut is 32mm. Standard chain is a 525 with the sprockets 15 tooth front, 41 rear (2TK model).

Renthal part number for a 14 Tooth front sprocket is 289-525-14p

For gearing calculations across the full range of sprocket combinations, see the gearing charts.

Oil Cooler

An interesting question popped up on the Yahoo list, namely:

I believe there was a past post that stated an FZ600 oil cooler could be
used on the FZR400. As I race the 400 here in Texas heat I was thinking
this would be a good idea. Anyone have any knowledge or experience
regarding this modification?

Well of course on the 2TK model, we have one fitted as standard but the following reply is of use to us all:

It is a direct bolt on. You remove the oil filter cover, oil filter and the
center tube, spin on the oil cooler base plate, put in the center tube, oil
filter and cover, then bolt on the oil cooler lines and you are done. The
biggest challenge is how to hold the oil cooler. I ran a couple of zip ties
through its mounting points and "hung" it from the radiator. I had a 4/6
and was running the 600 radiator. I built an aluminum radiator shroud that also helped. The guy who bought the bike is still having trouble with the bike running too hot, but he rides it in town more than I did (not at all).
It looks like I will be putting my F3 radiator and a Spal fan on it (thanks
to Jon Buck's pictures and information) to keep him happy (he gives me my pay check). If I do that I will have an oil cooler, 600 radiator and
aluminum shroud all for sale soon.

I do owe a couple of people on the list pictures of the shroud. I have not
forgotten, I just have not had time to get the bike back from Jason to take
them.

Todd

Spark Plugs

CR9E plugs are standard for the 2TK - why is this when the FZR400 uses CR8's? Because the sp model was for the race track so they fitted colder plugs - cheers Neil :)