Power Loss?

[Kawa mojave]

Ok this bike has fought me ever since i bougt it. Ok so far I have redone the carb put new intake valves in(originals were cut and sucked up into the head. After these two fixes the bike ran great. Over the wkend i took it to a local race. During the time i came off a jump and then went into a turn and the engine(i think) let out one loud tink. After that it lost power. You can ride it for about 10 secs then it shuts down. The engine now has developed tinks that come from the engine.(I think) I have no clue what is wrong unless it is just over heating. If anyone has any ideas can you please help.

[rednek426]

what bike is it? year and so on.

just off the top of my head, maybe a retainer wasn't set properly on a valve and now it's just floating, hitting the piston.

[Kawa mojave]

The bike is a 1987 Mojave that has been rebuilt mutiple times.

[ZX-2R]

Do a compression check, wide open throttle...safety switch turned to off... when you crank it over to prevent damaging the ignition system...see if things are equal...if they arent then pull the head and check the pistons closely for cracks, and check the head gasket as well, real close on both of them. worst case pull the jugs and see if the pistons, rings, wristpins, wrist pin rings, rods, bearings...you know the drill...it is possible that one of the valve springs broke, circlip came of or even a retainer ring is bent...let us know...that is part of the FORUM!!!

[nathan600r]

Well it sounds like you've probably ruined the motor, I would try and get a new motor, just because of all the problems it has had.

[ZX-2R]

Take it apart...the uncertainty is killing us...no sense getting a new motor, yet, since you don't know what you have inside...like rednek426 said it could be just a retainer spring from a valve...there isn't much inside that can go wrong...that will destroy it...so take it apart and let us know!!!

[Kawa mojave]

Well I found out what it is, the head is junk. The last owener recut the valves so that they would kinda seat and now the head just keeps pulling the valves up into the head.

[ZX-2R]

At least it's not an entire motor bottom end and all. Thanks for the update and let us know what it cost you and all to get her back on the road!!!

[joey]

I would like to add that if you just do the head and not the piston and rings those will fail shortly after you replace the head. My recommendation is to a least hone the cylinder and replace the rings.

[Kawa mojave]

The quad is now fully functional again and it only cost me $175. I found a guy who broke the kicker gear on an engine and he didnt want to split the case so I just took off the top end and dropped it on my engine since the rod seems to be in good shape.