Engine rattleing after complete Rebuild
-
@zx125 When rebuilding the engine, you must ensure that you timed it appropriately.
Whilst on a two stroke engine there are no cam shafts to time, a lot of engines still have timing marks. On these engines the timing marks denote top dead centre on the crank shaft and the balancer shaft.
These must be timed correctly otherwise you will encur excessive vibrations, and likely ringing, from your engine.
Are you confident that you reassembled the balancer shaft appropriately?
-
@calum Thank you for your answer. Yes I´m confident that the balancer shaft and crank align proper acording to my repair manual. On my engine there is one mark on the cranks gear and and one on the balancer shafts gear and these are aligned correct. I think they can only be alinged in 1 position because of the keyweys and the 1:1 gear ratio but please correct me if I´m wrong here.
-
@zx125 Sure, as long as the timing marks are aligned then that's fine.
The clutch basket has a rubber union connecting the primary shaft to the output shaft.
This rubber can deterioate over time. Did you notice any slack in the basket.
I'm just trying to throw ideas at you for noisy operation.
On that note, the clutch plates themselves must also be balanced. I assume this was done correct. This will also cause noise.
-
@calum I realy appreciate any ideas and experiences.
The dampers in the clutch basket are worn and there is some play in it but the noise does not seem to come from the right hand side.
I have assembled the clutch according to the manual as well so this should be fine.
For me the noise seems to come from the left hand side of the bike but I am not sure if any part of the starter clutch or flywheel could make a sound similiar to the one in my video. -
@zx125 The powervavle covers have bushes on them. When they wear they rattle. And apparently can cause the engine to seize believe it or not.
So make sure the powervalve end bushes are in good condition
I think this was the video I saw on it.
https://www.youtube.com/watch?v=4Rk8a51VqBc
https://www.youtube.com/watch?v=REPjGEhrZKQ
Description:
Finally its time to make a start rebuilding the 'top end' of the Yamaha TDR250's engine. Due to a previous Power-valve to piston contact causing immediate engine seizure I performed a complete top end strip down to see what had gone wrong...
