Transmission Problem?? vibration and noise, please help!

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Peter T
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Real Name: Pietro DiMascio
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My Motorcycle: Daelim Daystar 125cc

Transmission Problem?? vibration and noise, please help!

#1 Unread post by Peter T »

Hello there everybody!

I'm actually from England, and currently living in Spain, and I'm really hoping there may be somebody on here who can help out.
Appreciation in advance if so!! ,-)

Ok, I have a 4 stroke, single cylinder bike, that for some time now have been vibrating (coming from the engine area) between 6 and 8K rpm, in all 5 gears!!

This is accompanied by a rough feeling and engine noise and of course other area bike rattles!

OK, so, I have changed the chain and sprockets, the generator coil and magnet/flywheel (which showed signs of damage), crank position sensor, checked the engine mounts (which did actually break at one time but are now all welded-up again). I have replaced the valves (one had broken/worn on the top head) and replaced crankshaft bearings. I have had the crankshaft checked for balance too. All OK. The mechanic i was recently working with assured me that he had found nothing obviously wrong with the engine at the time of replacing the crankshaft bearings and checking its balance/alignment.

But, still I have this dam vibration! accompanied by a rough (not right at all!) slightly-metallic sound coming somewhere from the vicinity of the engine, but that vibrates through the whole bike - almost totally/only between 6-8krpm.

I guess the only area I have not examined now is the transmission/clutch. I have not suspected this simply because the vibration appears always around the same 6-8,000 rpm area, and in all gears!

Possible Clues:- I have also noticed the tachometer (at the troublesome rpm) moves erratically, and is not nice and smooth as in other rpm's. There are no warning lights coming from the Engine Management System at all. I have also noticed that as I depress the clutch ready to change gear in/or above the 6-8krpm range (and there is that moment of no-gear before the next gear is engaged) then the vibration/noise becomes VERY noticeable, as the engine rpm momentarily drops back down through that rpm range.

Any ideas??

I'd really, really appreciate anybody's advise or suggestions. I cannot really afford to pay any more garage bills, especially for something that may not cure the problem. (sure there are many here who cash relate to that!)

Your replies are most appreciated ,-)

Peter T.

NB. over the course of the last 12 months (approx. 14,000km) other things have broken (mainly brackets etc) on the bike because of this dam vibration. Would love to nail this once and for all.

blues2cruise
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Re: Transmission Problem?? vibration and noise, please help!

#2 Unread post by blues2cruise »

Did you fix your problem?
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Peter T
Rookie
Rookie
Posts: 6
Joined: Tue Jan 14, 2014 12:57 pm
Real Name: Pietro DiMascio
Sex: Male
Years Riding: 12
My Motorcycle: Daelim Daystar 125cc

Re: Transmission Problem?? vibration and noise, please help!

#3 Unread post by Peter T »

No, Problem still as bad as ever.

Basically the vibration/noise (sounds/feels very unhealthy) appears between 6 and 8 thousand rpm.

Also, worth mentioning that as i change gear, engage the clutch, and the engine revs. fall for a moment, just before new gear is engaged, the vibration/noise becomes VERY bad.

This is the only additional thing I can say, over and above what I mentioned in the initial post.

Anyway, any help would be really appreciated.

Cheers!

(ps. areas I am suspecting are worn gears/transmission bearings, that kind of thing), but in all sincerity I am so tired of this, been going on and worsening for more than a year and 3 mechanics here in Spain have not been any use whatsoever.

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