Belgian 3TJ hybrid for endurance racing.

[ivosonck]

Hi all,

I'm Ivo from Brussels, Belgium, and together with one of my mates (Roeland) i will be racing the Belgian endurance series known as the "No Budget Cup" (those of you who read PB will know it...). Basically, as long as your frame and engine are from 1990~1999, anything goes...

So after i binned my stock FZR400RR 3TJ on the track in 2008, we decided to use 2009 to prep a hybrid 3TJ (the only one in belgium as far as we know) to compete in the 600 class in 2010.



Unfortunately, being in Belgium posed quite some problems... There's no FZR community here (barely for 600s, let alone 400s), the few bike breakers we have here are bloody criminals and the private 2nd hand market (even for damaged bikes) is twice as expensive as in the UK

But, no fear, because with some good pointers from Mach 1 at FZRarchives and the almighty ebay.co.uk at hand, we set off on our parts hunt

[ivosonck]

So what did we need transform our little 3TJ in a proper race bike...
obviously, we needed an engine, but as mentioned before, that was not going to be an easy find.
While searching for a good donor bike, we already got started on our wishlist for the chassis mods.

we would be racing against R6s among others, so we knew we'd be down on power no matter what. So we needed a nicely finetuned chassis to focus on high corner speeds => chassis and brakes needed attention.

for the "coolness" factor, we wanted the bike to be as stock looking as possible.

For the front end, i wasn't confident in my abilities to replace the entire front end with that of another bike, so i went looking for forklegs to replace the standard ones.
As it turns out, first gen R6 forks have the same diameter as the 3TJ ones, so i found an R6 front end.
Of course this meant i needed brakes and a wheel to match, which was solved with first gen R1 items.

In the picture below you can see the first matching up of the parts, with the stock yolkes => easy fit, though quite tight.



So that was good news! now we just needed to adapt some parts as the width of the 3TJ yolkes is 5mm smaller than the R6 ones.

The longer fork legs of the R6 allowed us to put some Valtermoto alloy clip-ons above the top yolke. Some comfort is welcome for 4 hour races!!

[ivosonck]

Gaining 5mm for the wheel spacers was no problem. quickly drew out some smaller ones that could still accept the original R1 dustcap and had them CNC'd by a mate...

left : new smaller ones right : original ones


Spacing out the blue-spot calipers took some consideration though...
Originally i drew up some adaptor plates, but even with the tightest fit these would still have been quite cumbersome due to the offset angle in which they are mounted.

Finally, we took a bit of a gamble and tried to machine down the calipers themselves. They only needed to have 1,25mm shaved off, so structural integrity was never a problem, but we had to make sure the were perfectly horizontal in the CNC lathe...
But never underestimate a professional's skill, as my mate once again came through with the goods.

[ivosonck]

with everything adapted, we put the front end together, and it all matched up nicely...
Some Staubli quick release brake lines i had lying around bridged the additional length we had to cover due to the clip-ons being above the yolke (a bit overkill though )



A bit of ebaying, and we sourced ourselves a nice Brembo PR19 brake master cylinder as well...

Now, with the front end mostly sorted, it was time to get going on the back end.

[ivosonck]

2nd hand racing shocks for the 3TJ proved quite difficult to find, even in the UK (or i wasn't looking in the right places, which is more likely).

One day another friend asked me if i could deliver a rear shock to our local suspension guy for a rebuild. This particular item was a GSXR 750 SRAD Ohlins full race shock.
I couldn't believe my eyes (and my micrometer) when i measured the top and bottom shock mount widths, and found they were spot on the same as the 3TJ ones!!
Quickly tried to fit it in the Fizzy...



Now that looks lovely, doesn't it?
Unfortunately it also revealed the Ohlins shock was too long. the spring rubs agains the swingarm cut out (even with the height adjustment on the shortest position).

Anyway, i was sure i could get the length issue sorted, so i offered my mate to buy the shock off him and he kindly agreed to it (thanks olivier!!)

[ivosonck]

So to shorten the rear shock assembly, i popped out the inventor drawing software, and soon enough the CNC was hard at work again!
Soon enough we had an LK7 steel grade new top shock mount ready for us!

left : shorter top shock mount right : original part


time to fit it to the frame and check for clearance again :



some racesuppliesdirect rearsets add to the increased ground clearance. Have them on the Aprilias as well and I think they really are good kit for the price...

[ivosonck]

Now, while all this was going on, we still needed an engine...
After a lot of searching without any results, we were suddenly faced with two options out of the Netherlands.

One was a crashed thundercat, but the low mileage engine still looked OK.
The other one was another FZR400RR which had a thundercat engine fitted already. But despite reasonable look from the pictures, i was doubtful, because of stuff like "only 20 miles ridden with new engine" or the way to stubby (post-crash) exhaust...

I decided to take the risk (and the 400 mile roundtrip) and went to check out the FZR.
The hybrid build quality did prove to be very questionable and the engine ran partly on 3 and partly on 4 cylinders... but when i testrode it and it ran on all 4 cylinders, it ran good... real good! a lot of torque!
So i got their asking price down to a reasonable level and took it back home. At least we'd have a lot of spares with two bikes now!

So we fixed some of the previous owner's issues and started bolting all the chassis parts up to the newcomer...

[ivosonck]

Originally, the engine was running on 3 cylinders because one of the seals in the 2nd carb was squeezed. We replaced this with a new one, and changed the spark plugs to irridium NGKs at the same time...
The engine ran fine for some time, but started misfiring again later. We finally found out that while we were experimenting with the standard 400 airbox (due to noise regs) the engine was running that rich that it fouled the plugs. When we were advised by an experienced dealer that we could run K&N pod filters without having fear for noise, we changed the plugs again and everything has ran smoothly ever since.

So now it was time to have a first track outing! Just needed to put some temporary clothes on her, as we were still waiting for our BB plastics fairings.



Result from our first ride : everything works!! the chassis felt really good and stable, while still steering quicker than anything else around us.

[ivosonck]

So now we had the intake sorted, but we still had that obnoxiously loud stubby exhaust to take care off...

Regulations stipulate a noise limit of 95dB. Yes, you read that right... 95dB!! That's more quiet than some stock bikes...

So we went to one of the few exhaust specialists here in Belgium, DAM exhausts (http://www.damexhaust.com" onclick="window.open(this.href);return false;), with the clear instructions that he could do whatever he wanted, as long as he could guarantee us that the bike would meet noise regs...

The result is a beatifully crafted long silencer (which suits the lines of the bike as well!) and he made some modifications to the headers as well to take care of the clearance to the back of the frame. We have to wait untill our first testing day (next weekend) but we're confident the bike will be quiet enough.



With the exhaust sorted, we brought the bike to our engine guy to get the fueling sorted.
This was done by the specialists at Ramaekers Motoren.

A few days later they called us up to bring us the good news : 95.5 hp at the wheel and great pick-up at any revs above 6000rpm



Now that is a flat torque curve for a 10 year old 600 engine!!

[ivosonck]

In the meantime we took care of some other items :
- retrimmed the clocks and replaced the speedo with an Alfano lap timer
- maximally repositioned the rad to avoid any chance of contact with the front wheel.
- added a radiator protection grille as in endurance racing you tend to get a lot of crap on the track...
- lengthened the fuel line and reserve wire to the fueltank so we can flip it up completely when working on the engine
- raised the tank for better airflow to the K&N filters.
- used one of the original 3TJ heel plates to create a sharkfin (race requirement)
- had a custom 50t rear sprocket made
- cut and rewelded the rear subframe to create 3cm extra room (I'm 6 foot 5, so i need it )
- fabbed up holders to catch the rear paddock stand
- adapted R&G front fork protectors.
- safetywired everything

I'm probably forgetting a ton of stuff, but it's these little things that complete the bike in the end...

In the meantime our BB plastics fairings arrived, including an R6 front fender.
So we went about to weld the appropriate brackets, fitted the fairings and started painting.

We decided to go for Yamaha's 1990 500cc GP contender (the YZR OWC1) as an example



So while Roeland took care of the masking and painting... (with cans, obviously )



...I took care of sanding down the fuel tank (what a bitch of a job that was )