How much realible is the ZXR engine for race use.

[ancozxr]

Hello guys,

How much reliable is our engine for race use (not track days).

I read the last years in this forum for bikes 75+ Bhp (Rogers one is 83 if i dont mistake) and wondering what is the rebuilt issues.

The Factory made a bike with 55 Bhp i most cases, the tune to this level is OK?

I dont read anyone to use special parts (because of F400 regulations) as the WSBK teams (steel rods, forging pistons, special cranks)

and the only change is the steel valves.

Can someone tell us in rebuilt what change most times?

For ex.

Crank fail is common?

Piston crack ?

Con-rod crack ?

Piston ring damage?

Barrels sizing ?

Thanks,
Andreas
Greece.

[AFM327]

My motors make 72-74 Hp last one went 2.5 years of racing, probably between 50-60 races and several track days per year when it spun a bearing during the second hour of an endurance race. I think the motors are pretty durable. Haven't and any other failures, A buddy had some valve to piston issues but that was probably his fault due to over revving on a regular basis.

[ancozxr]

My motors make 72-74 Hp last one went 2.5 years of racing, probably between 50-60 races and several track days per year when it spun a bearing during the second hour of an endurance race. I think the motors are pretty durable. Haven't and any other failures, A buddy had some valve to piston issues but that was probably his fault due to over revving on a regular basis.

That is amazing.

2.5 years of race is cheap for rebuilt cost, can u send me a p.m with the mods that u have and still so reliable.

The only mod I know by 1st hand is the FCR carbs that sell to U some years ago.



What oil U use and still so reliable?

Over rev is common to valve-piston romance....

from 14.500 max rev, your friend what limiter run ?

[AFM327]

Nothing fancy, flatslides, pipe, skimmed head, valve work, crank balanced, running the SP cdi with the stock rev limiter.