E: Engine Rattling Comet

Colin

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VOC Member
I've just got my Egli Comet back on the road after a few years SORNED. Straightforward recommission, a general check up , new battery, oil tank clean out change all oils, reset all clearances, adjustments etc new plug, and a carb re-tune check chain. It started easily and, after the carb tune ticked over regularly and went well.
I had acouple of rides clocking up around 120 miles in total. It accelerated well was happy to cruise around 70 mph and still had some left. Generally no problem, then on the next ride, at 50mph in top (and corresponding revs in lower gears) a rattle started up. Below 50 it sounded exactly like it always has.
The rattle sounds exactly like a loose metal mudguard. I can find nothing obviously loose and have to conclude it is in the engine.
It runs as sweetly as ever below 50 and sounds about to fall apart above that,
Has anyone any ideas please?
 

Robert Watson

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VOC Member
Time for a stethoscope? I had a nasty rattle once, turned out a loose tank bolt had let the tank contact the oil filler tube on the UFM. Took a bit of sleuthing to find it.....
 

Trickymicky

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VOC Member
After a long lay off, the innards of my silencer came adrift, which started with a rattle, and ended with them blocking the tail pipe.
 

macvette

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Non-VOC Member
I've just got my Egli Comet back on the road after a few years SORNED. Straightforward recommission, a general check up , new battery, oil tank clean out change all oils, reset all clearances, adjustments etc new plug, and a carb re-tune check chain. It started easily and, after the carb tune ticked over regularly and went well.
I had acouple of rides clocking up around 120 miles in total. It accelerated well was happy to cruise around 70 mph and still had some left. Generally no problem, then on the next ride, at 50mph in top (and corresponding revs in lower gears) a rattle started up. Below 50 it sounded exactly like it always has.
The rattle sounds exactly like a loose metal mudguard. I can find nothing obviously loose and have to conclude it is in the engine.
It runs as sweetly as ever below 50 and sounds about to fall apart above that,
Has anyone any ideas please?
Try running on the stand, increase revs until you hear noise. If its in the motor, stop if not you may be able trace the resonance. It doesnt take much contact to cause rattles.
 

Chris Launders

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VOC Member
You will find it easier with an assistant, to hold the bike and operate the throttle, also to triangulate where the noise is coming from, riding it will only disguise where the noise is actually coming from.
 

vibrac

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VOC Member
I worry more if it doesn't rattle :)
seriously that silencer suggestion is a good starter there is no corrosion protection in there and its been empty of fumes and heat a long time
 

Gary Gittleson

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VOC Member
And if it's something like a loose mudguard, try rapping it with the heal of your hand. A friend's Rapide had a loose bolt on one of the front mudguard stays that I found by that method. It took several shots to find the one loose bolt. My friend doubted my sanity for a bit, but then all was put right. Let me see. Person, woman, man ... I'd better stop there.
Gary
 

erik

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VOC Member
The magneto cowl likes to rattle,even if the screws are all fixed. Erik
 

Peter Holmes

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I don't think this will apply to a Comet, but a rattle that drove me insane until I tracked it down was the chain oiler on a twin, if the pipe just brushes the chain the rattle resonates through the UFM, I had totally convinced myself it was the magcowl loose on the bottom studding, so I epoxy'd the studding into the magcowl, but the rattle was still there driving me crazy, I was so relieved when I discovered the culprit.
 
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