Noise from Flywheel area - Sounds tappety By potwashman (Read 402 times)

[potwashman]

Hi, I have a 139qmb engined scooter that had a 80cc BBK last year that has been running perfectly.

Last couple of weeks it developed an oil leak coming from base of Cylinder barrel on the engine. I ordered new gasket and replaced it. Before moving barrel, etc I made sure it was at TDC and made sure that piston not moved when put everything back together exactly as before.

Sure enough, wouldn't start; turning but just not firing up.

Took off the head cover, re-gapped (again at TDC with the flywheel lined up with the T and the holes on camshaft just where they should have been, took spark plug out, turned CLOCKWISE to line up, put is back together and fired up first time.

However it sounded really tinny & tappetty (is there such a word??) so I again took took off cover and re-checked the gap (.004in). Put back together and sounds just the same but the noise seems to be coming from the flywheel area. On tickover it is a little noisy but as soon as revs increased it sounds terrible.

I've looked on another forum and someone seemed to have the same problem but it never got resolved so hoping I can get answers from you guys.

There is plenty of oil, bike starts up and ticks over without wanting to stall, just sounds wrong.

The bike rides just as it did but sounds as if it will blow up at any second.

Look forward to hearing your advices.

Thanks

[jct842]

Go back and double check, it was working, you changed some thing to stop it from working. It is possible you over looked some thing Ticking usually involves a gap, if it was not there before you took apart and is now look there.

[potwashman]

Thanks for reply. However, I have already checked it (re-gapped 3 times within last 24hrs). I have re-gapped before. When I first did the BBK (nearly a year ago), when I put it back together the gap was too big and although bike fired up it was very 'tappety' so I know what a badly adjusted gap sound like and this is similar but different (if that makes sense). It is a uniform noise/tap that increases with engine speed.

I know what you're saying, if it worked before I changed something then I must have done something wrong/different when putting back together but I really did put if back just as before.

Just as I'm typing this I'm wracking my brains going over the procedure but can't think what's happened.

It's not just coming from the head (like before when I didn't set the gap right) but seems to be mainly from the flywheel area or just behind it. Could the chain guide(black plastic thingy)somehow be catching on the chain if it's not seated correctly. When I put the chain tensioner back in the spring was still intact and I'm pretty sure I heard it engage when it was 'plunged'.

Any suggestions appreciated.

I'm gonna still use it tomorrow then when in from work I'm going to bring into the kitchen (no garage) and take apart & do again. I'm sure that's going to go down well with my missus.

Thanks

[cyborg]

Bingo i think you hit it,,,cam chain tensioner not correct,,,something went wrong,,,youre on your own with the little woman,,,i tried pulling the restored classic triumphs and nortons in the living room,,,,nada zilch zero,,,,i got nuthin but the ice queen for more than a week,,,,i can sympathize,,,,,let us pray

[potwashman]

Yeah, I've convinced myself that's the only thing it can be but I'm wrong more than I'm right so fingers crossed. Can't put off the inevitable, I'm going to do it now in the kitchen otherwise I'll just be thinking about it all night. Nearly 8.30pm here in the UK, so just gonna have a cup of tea and drag it in the kitchen.

I'll post later how it went!!!

Cheers

[potwashman]

Yaay - All sorted. Purrs like a kitten (that smokes 60 a day). Just as I eventually thought, it was the chain guide. I cant have seated it properly when I put it back and it was catching the timing chain.

Bit cheesy to say but I've got to thank the forum. By putting prob down it made me re-think everything I'd done and by process of elimination it made me realise it must have been the guide (glad it was or I would have really been stumped). Off to bed now, up for work in 6hrs. Missus didn't bat an eyelid and even let me drink some of her cider, what a woman!!!!

See ya

[cyborg]

Nice glad you got it sorted,,, happy trails