GP 200 Vibration and noise.

[emo5c]

Hello all. I have a 1984 Sil GP200 with a few little problems and wondered if anyone can point me in the right direction to sort them out. The engine has only done about 250 miles since a rebuild and i'm now beginning to up the revs a bit. There is quite a rough patch as I go through the 35 to 40 mph area in top (and corresponding speeds through the gears) and makes the machine shudder, like it's resonating. I've done the usual checks of nuts bolts etc although I may have missed some. Also when the engine is ticking over there is a bit of noise from the chaincase which disappears when I pull the clutch lever in.
Any ideas please.
Thanking you in anticipation.
David.
PS. You may find a slightly different version of this on another part of the forum but I wasn't sure where to place it. Sorry.

[Soulpunk]

let the oil out. put chaincase cover off.
put exhaust on and start again.
then you can locate maybe better where the noise is from.
1 minute running and not changing gears won´t harm the oily mechanic.

[Chris Tindal]

I have the same problem with my Silver Special. Apparently its excess play of the clutch due to worn bearnings. I rebuilt the engine last year but used the innocenti clutch bearnings, which was false economy as I am now about to replace them. It is an easy job though as long as you have a clutch compressor and holding tool.

[mickdale]

have you overtightened the engine mount threads?
- may help to loosen them off 1/8 turn from tight

[emo5c]

Hi all. thanks for the tips, i'll give them a try. Changed the gearbox oil (only got a dribble out) and got a bit of a smoky exhaust on starting up, poss crank seal (aghhhhhh) although it might be that I mixed the 2 stroke a bit too strong. Drained it off and refilled with the correct mix and when I get my new gearbox oil in i'll take it for a run and do a bit of praying. Watch this space.......

[emo5c]

Hello again all. Tried all of the above and still had the clouds of smoke, the engine is on my bench mostly stripped but awaiting the crank removal tool. As the engine was only built about 270 miles ago it is all in perfectly clean condition, i'm hoping now that when I get to the bearing retaining plate seal it is actually damaged or the seal plate is warped (apparently common with the alloy ones). Glad I decided to do it myself though as it's a lot easier to work on than any of the motorbike engines i've stripped.
Will keep you informed.

[bristolmod]

crank out of true???

which causes the seal to blow IDC?

Chris

[emo5c]

Well! Thanks for all of your help and suggestions...problem solved at last. Decided to strip engine and replace possible faulty seal but on removing the drive side seal plate found that the engine had been put together WITHOUT the gasket, no wonder the gearbox oil disappeared and I had clouds of smoke. It smoked a bit when I first got it but put that down to rich 2 stroke mix which eventually disappeared, obviously when the gearbox oil ran low.
I won't be using that dealer again and neither will a few mates who were looking to purchase scooters ready for next summer.
Anyway, all seems ok now so keep fingers crossed that I don't encounter any other problems.
David

[cezeta]

easy mistake to make.........if you don't do it for a living

the insanity of some bike and scooter shops......i went into a long established bike and scooter shop the other day to see if they could fit my tubeless tyres to my tubeless rims. i was told that there are no 10" tubless tyres on the market and i was laughed at in front of the other customers. fortunately being an obnoxious tw@7 i offered them to bet me that they were wrong, they wouldn't put money on it but accepted. i showed them the word "tubeless" on the tyre in my hand then showed therm the same word on the range of schwalbe and continental tyres on their rack. "must be a recent thing" they said

f@@king morons or what?

[emo5c]

Managed to get a set of oil seals and a gasket set out of them but received no explanation or apology for the ommission of the part that caused the problem....never again...
Bike seems to be running ok now, just got to set up the carb as i've also fitted a scootrs sports tuned exhaust to it, will probably have to do a plug chop. Anyone else fitted one of these? did you have to jet up the carb at all?
Thanks everyone....