Ring ring

[raz]

I experience a strange intermittent ringing sound from my engine when idling. It sounds pretty much like a Ducati clutch but I'm pretty sure it comes from the timing chain or alternator or something else at the very front. It's more or less intermittent (maybe it shows more at certain idle rpms) and I'm pretty sure it's only at idle, with or without clutch enganged and in gear or not. My imagination pictured a somewhat loose rotor, scraping into the stator but removing the alternator cover just showed everything seems OK in there. Is this a pretty much normal noise from the cam chain or something, or does anyone have a clue? It doesn't sound good to me. I did have a look at the chain and stuff during winter and everything looked fine, apart from a very weak tensioner but I understood from some reading here that's just normal.

[Guest ratchethack]

. . .everything looked fine, apart from a very weak tensioner. . .

Raz, I've never had this happen, but it sounds to me like the perfect recipe for the cam chain whipping a bit, just enough for the tensioner to contact the timing chest. From what I've read, unchecked, under the right conditions the chain itself can eventually saw quite a notch in the cases if it gets too loose. Evidence of contact should be fairly obvious from inside.

[Baldini]

.... It doesn't sound good to me. I did have a look at the chain and stuff during winter and everything looked fine, apart from a very weak tensioner...

 

Sounds like it could be timing chain flapping around. Loose chain will eat into casing which is a bad thing....

KB

[raz]

OK, it seems like a plausible explanation. I couldn't see a single trace of wear when I had it apart, but on the other hand, this is just a couple of seconds now and then and there's oil all over the place so maybe it needs to be even worse and for a prolonged time before much wearing. I know "some idles" are much better than "others", meaning sync, valves and mixture. Right now this ringing seems to be at its worst and the idle is not really harmonic right now. I'll soon put the My16M back in service again, that will probably make things a lot better.

 

Thanks for the input!

[KiloSjon]

I have another question on this subject. I hear a high tick, like a chain tapping. It is in the same frequency as a valve tick, but its "rythm" is varying. It seems louder at 2000rpm with the throttle almost closed. I think it sounds like a disti chain, I had that on my previous bike. Reading this thread makes me a bit nervous, since the advice is to solve it immediately...

 

The question is: how hard is it to replace or adjust the chain tensioner? Does it require the engine to be removed, or is it just removing the alternator cover and the timing cover while the engine is in the frame?

 

I plan to go on a big trip in 4 weeks, so I want to have this fixed asap...

[raz]

I have another question on this subject. I hear a high tick, like a chain tapping. It is in the same frequency as a valve tick, but its "rythm" is varying. It seems louder at 2000rpm with the throttle almost closed. I think it sounds like a disti chain, I had that on my previous bike. Reading this thread makes me a bit nervous, since the advice is to solve it immediately...

 

The question is: how hard is it to replace or adjust the chain tensioner? Does it require the engine to be removed, or is it just removing the alternator cover and the timing cover while the engine is in the frame?

 

I plan to go on a big trip in 4 weeks, so I want to have this fixed asap...

Fairly easy. Alternator cover, stator, rotor, front engine mounts. Then tilt that engine mount subframe forward to get room.