I need a target!

[wera123]

Finishing up a few ZXR750 builds and looking to do a FZR400 race bike, but I need a target to get me motivated?

What say you as a motivator?

Horsepower? (limited <500cc)
Lightness? (what is the lightest out there?)
Fuel Injected? (I really like my flatslides)
3TJ? 3EN? 1WG?

My motivation is do the build for less than 3,000 Euro

Ideas? Thoughts?

The slate is clean, but the fun will start soon.

[Evilchicken0]

Depends on the race series rules - you'll be better off getting a race / track bike to begin with but look for a FZR400RR SP, the SP has the usual upgrades on the road bike, if your very lucky it might have flatslides but it's unlikely .... look for adjustable suspension, although the rear will probably non standard.
The sp engine has lighter valve train an oil cooler and an extra plate in the clutch, there's a close ratio box too although some racers preffer standard ratios because it's easier to get a good start.

[wera123]

Good info! Are the both SP's (3EN & 3TJ) the same spec motors?

We are a Ohlins Race repair center here in Germany and the plan is to custom make a TTX shock and something cool for the front forks.

[Evilchicken0]

No the 2TK SP is a 1987 bike
The 3TJ SP is from 1990 onwards and its completely different. The TJ's rear shock is long and the standard rod is a small diameter. They're quite low to the headstock and the top yoke is cranked down to save weight I guess the original forks are 20mm cartridge ... good for what they are but the spindle screws into the left leg with no pinch bolt.

SPs are getting hard to find, if you're going to do the suspension with yellow springs then you might find a standard RR in good condition is easier. If you get one in UK I'll ride it over for you :)

[willandrip]

Would advise you choose 3TJ series SP over 2TK.
Spares availability is much better and more economically viable.
IIRC Tyre choice is better not having wheel size limitations =can be easily overcome but one bit more that is just not quite right !!!!
You are in the ideal position to modify/upgrade rear shock.
What were you contemplating for front ?????
If original carbs are missing suitable replacement flatsides do come up at a sensible price (a good set only made £50 about 2 weeks ago )= most get shot of them =they are inept at tuning them and cannot use them properly.ie "Wide open from low revs rather than feeding fuel to engine as required hence engine bogs down "
These carbs run a treat-I took the 2TK out and rode it like my TZ 350 and they performed perfectly !!!!!!
Stick to your plan with the SP and do not be tempted to use a stock engine,the benefits of close ratios far outweigh the high 1st gear for starts off the line. In a race you start but the once,corners are multiple.!!!!!!!!!
With close ratio and higher revs and a bit tuning you will sail past others on similar converted road engined machines.
I have a copy of the 2TK SP workshop manual supplement if required (In Jap but if you are a petrol head you will figure it from specs and diagrams+excellent wiring diagram)


Try to see if Kayla joins in here=
I was at Projection Components last week and she had just fitted a lightweight Brembo rear caliper to a bike that had just done the Manx and the man was there. He had his engine up to 90+ rear wheel BHP on accredited dyno.
I got a good bit of info from him but lost the fag box his no. is on.!!!!!!!!

Please keep us informed on your progress with rear suspension.
You will be able to build a top notch one for 2.5k and will have the benefits of custom suspension at trade price and labour for probably nothing . ( Lucky barstool!!!!!! )
I possess a 2TK SP and it is the rear suspension awaiting a suitable upgrade that is preventing progress on the rebuild/upgrade/refurb. (I source all parts before initialising work).
I have already posted a request for thoughts on a suitable replacement -MUST HAVE REMOTE RESERVOIR- .

What ZXR,s have you???
750 L1 California Import (Ninja tank decals {I hate it} with 900 B3 engine /carbs/Muzzy gear.
750 L3 (Monster Energy colour scheme) track bike on road.

Looking to get a 400 L3/4 to do next when Yamaha's finished !!!
That colour scheme is mint !!!!!

[Evilchicken0]

If original carbs are missing suitable replacement flatsides do come up at a sensible price (a good set only made £50 about 2 weeks ago )= most get shot of them =they are inept at tuning them and cannot use them properly.ie "Wide open from low revs rather than feeding fuel to engine as required hence engine bogs down "

I think those were described as flatslide but they were the standard CV carbs.

[wera123]

90+ rear wheel BHP on accredited dyno is massive!!!!!!!!!!!

The ZXR750 (839cc) is all stuff from the German Kawi SB team. Everything is kit with a one off fram. oil pump and cams are gear driven..magnesium oil pan..41mm FCR's 2012 Spec custom Ohlins TTX shockand FGR800 pressurized forks.....blah...blahhh..blah..We built 2 as a Golden Era project.

Back to the 400. I built several FZR560's in America but we were limited to the 1WG and the rules were free.

Fork>Hmmmmm...something adapter with custom yokes and a pressurized cartridge.

I have a set of 33mm & 35mm flatslides(for 600 project) but a nice set of CV can be friendly.

[willandrip]

The ones I saw where flatties mind Boris =They wern't on here or the usual places but an F2 sidecar site run by a man called Steve.
Geoff Bell has a tea chest full both from their TT entry bikes in the old 400 production class and for use on some 600's they run in slideys and are easy retrofitted.

[Evilchicken0]

Ah - ok

I doubt 90 bhp would last long, high 70's with some reliabily from a 400 is more usual.
There used to be a 440 kit but I don't know who made them

[rrsp]

tts did the 440 kit, but you need the pistons milled out as the valves will touch the pistons, they are nice bit of kit but they are not a easy fit,not specified for a yamaha, they are just a 440 piston to fit any re bored 400 basically, they do look like yamaha kit pistons that i have in yzf 750. 1mm oversize is the way to go, skimmed head,gas flowed,flatslides, pressured air box,ram air,l&b crank, lightened fly wheel, remove alternator,zxr rad, you will be looking at 80+ hp