KMX lost power, rattling/clicking sound from cylinder

[Myles Banks]

Ive got a 1989 kmx, and worked perfectly until I ran out of oil one day, and had too ride miles too get some more. Now the problem is, ever since it hasn't got that extra bit of power which is why I love it! Now I'm pretty sure that I may need new piston rings etc. but not sure? It has also started 'reving out' at maybr 9000rpm, which I have no idea why? is it a sprocket that is slipping? or a power valve/band which is clogged up or stuck....? all of these problems I need to sort out and adress but dont have a clue where too start, Im not sure on how to even strip the bike to have the engine free without taking everything off and going the long way round... basically i need someone too point me in the right direction of regaining the lost power, what it might be, maintaining it and upgrading it. ?Hope someone can help! thanks if you can!
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Why do I need a signature?

[ruck bodgers2]

top end rebuild i reckon . pistons probably caught a tan and rings shot loosing you compression to boot . i have not messed with that model bike myself so i can only assume certain things . if you pop your tank off and bits. would you have enough access to work without dropping the engine out the frame .
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throw it up the wall

[weasley]

I have the KDX, but the KMX look similar enough that it will be easily possible to get the head, barrel and piston out with the engine in the frame. It's really quite straightforward.

It's possible the KIPS valves are stuck, but I'd doubt it as they are pretty free-moving and lack of oil should not affect them too much.

Best idea is whip the head off and have a peek. Easier with the tank off, which will be a 2 minute job too. Remember to drain down the coolant before opening the head!
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[dangerousdave]