2003 Engine Question

[Venom06]

Hello,

I just purchased another 2003 Hayabusa for a winter project. After doing a full inspection I was quite upset with some results I found. The motor is on its last leg more or less. I did a compression test and all four cylinders are showing right around 120lbs.

Im not into building some 400 hp turbo busa so my question is this. Can I get the cylinders bored 20 over size and just re-ring it? I ask this because I cant seem to find any information on the actual material of the cylinders. Are these cylinders nikasil plated or not? Would it be cheaper to bolt on a small big bore kit? I really dont want to have to get into the whole mapping, power commander thing! I'm just looking for reliable horse power for long distance runs.

Any help or suggestions would be great as I really didnt want to get into a full motor rebuild even though I know I have to now.

If anyone is interested in a cheap 2003 engine that runs great let me know!:rofl: (Kidding!!!)

Cheers,

[kml666]

Are you sure it's the rings? Could be a the valves. A leak down test would confirm it. Maybe it just needs a cylinder hone and a fresh set of rings. Might not have been broken in properly and the rings never had a chance to seat.

cheers
ken

[Venom06]

Thanks for the reply Ken! I should have mentioned that the motor has close to 40000k on it. The reason why I say its rings is when I did get the engine running there was grey smoke coming from the exhaust at idle even when the bike was warmed up! Im sure the bike does need a valve lash adjustment. The valves did tick pretty good at startup but seem to quiet a little when the motor would warm up.

I dont think the oil was changed more then twice on this bike. When I did change the oil it was really black and a tad thicker then expected and that was with the engine hot!

Cheers,
Ray

[kml666]

If the motor has been maintained 40k is not a lot. I'd be willing to bet the problem would clear up with fresh ring and a hone job. No need to rebore if the cylinder to piston clearance is still with in spec.

Unlike a car, a bit of valve noise in a motorcycle engine is not necessarily a bad thing.

cheers
ken

[wiredleprechan]

I'm with Ken that if the motor has been maintained then 40K really is that bad. I would suggest a wet compression test which involves pouring about a cap full of oil in the cylinder before performing a compression test. The reading will either spike up on the gauge or will not change. If no difference between wet/dry gauge readings then you are looking at a valve problem or compression is leaking out some place else. But this will tell you if the rings are the problem or not.