Power loss

[AndyJay]

Think I'll have more luck with the lottery than I'm having with my 01 DT R atm .

Got a severe loss of power for some reason. Engine was reving fine in neutral and can just about get into the upper power band in first, but anything onwards it can't get past 5000 and idles at around 20mph. This all happened on my way home so haven't ran it since.

I've taken the top end off the engine and the piston, rings and cylinder all look fine - no signs of wear. There's no play in the rod either so the bearings are good.

Since buying it I've had a fair few seals go on it after running it in again - does this sound like it could be the left hand crank seal? I know the bottom end pressure is important with 2 strokes so could a leaking seal be preventing enough fuel getting pushed through into the cylinder when increasing the revs?

I'm guessing it can rev okay in neutral as it doesn't have the load of the gearbox and drive train applied which could play around with the pressure too?

Any advise would be greatly appreciated.

[Calum]

If it was a crank seal it would idle high if its the LHS or smoke heavily RHS.

It could be a number of things.

This website has loads of information on power loss. Check the usual suspects. Worn clutch plates will cause high rpms low power.

[AndyJay]

I'll have a search about.

The thing is the power to rev ratio wasn't an issue - the engine just wouldn't physically rev above around 5000 even with the throttle held open, as if it was in limp mode.

[declan]

@AndyJay was it wet out?