Rattle

[copperbusa]

I would like to confirm source of new rattle, left side, sounds like it is coming from the generator. First heard during a long low rpm drive (looking at cabins at the lake). It rattled when I blipped the throttle (at the end of the blip). Did not rattle after a fast 20 minute ride, but did after about 50 minutes, then didn't when let idle for a few minutes. Feels like it is heat related, really sounds like it is the primary chain. Bike is a 79 that was restored 3 years ago and has about 40,000Km on it (3,000 since the restoration by head mechanic at local Honda shop - since moved), engine cases have never been opened. Carbs were rebuilt/balanced during restoration and I have not noticed any material decrease in performance though clutch is starting to rattle a bit at idle, I have not adjusted the cam chains yet.



Primary chain?



Solutions?

[Tom Neimeyer]

I would suspect it to be alternator clutch slippage, fairly common. If you have not had that apart and inspected, you should do so. The spring will loose tension over time and the plates wear causing insufficent pressure to keep the clutch engaged and allowing it to "chirp" intermittenly.



I'll bet there are other threads about it if you do a search.



Cheers, Tom

[copperbusa]

Thanks Tom, I will search the threads, though this does sound like a marble bouncing around inside the engine case.



Regards.



Doug Cannam

[Terry]

Could this be a simple 'ping' rattle? My 79 sometimes rattles likes marbles in the motor whenever its REAL hot but only when taking off from a stop at low revs.

[bobber]

Could this be a simple 'ping' rattle? My 79 sometimes rattles likes marbles in the motor whenever its REAL hot but only when taking off from a stop at low revs.

That sounds like detonation. Too low octane fuel for the temp's so its igniting BEFORE its supposed too due to hot deposits on the piston crowns. Can cause some major damage if not corrected. IE higher octane fuel or adjust ignition timing to conditions.

[copperbusa]

Thanks for the replies guys. Just rode the bike into work (10 min ride) and all is quiet, but it's cold out (55F) and the ride wasn't long enough to generate some real heat. Obviously seems to be heat related. Not "ping rattle" and not detonation, don't think that it's the friction plates on the alternator (not chirp). I have run two tanks of premium through it from two different major suppliers with the same results. Will have to wait for a warm day when I'm not in the office to get it heat soaked.



Thanks again for the replies and stay tuned.



Regards.



Doug Cannam

[bobber]

Thanks for the replies guys. Just rode the bike into work (10 min ride) and all is quiet, but it's cold out (55F) and the ride wasn't long enough to generate some real heat. Obviously seems to be heat related. Not "ping rattle" and not detonation, don't think that it's the friction plates on the alternator (not chirp). I have run two tanks of premium through it from two different major suppliers with the same results. Will have to wait for a warm day when I'm not in the office to get it heat soaked.



Thanks again for the replies and stay tuned.



Regards.



Doug Cannam

55 degrees outside? Warmer than that here in Ft. McMurray!!!