'68 r50/2 rotational noise

[312Icarus]

My /2 has developed a high pitched rotational noise. Engine was redone a couple of thousand miles ago, with slinger service, new mains and cam bearings. It doesn't by pulling in the clutch, and goes up with speed but the pitch doesn't seem to change. I'll try to post a video so you can hear it.

(Can't seem to load an IPhoto video, anybody know how to configure it so I can?)

Icarus

[312Icarus]

Here is the link to the noise mentioned above:

https://youtu.be/JNnBu7M5o2c

Have a listen and tell me what you think.

Thanks

Icarus

[312Icarus]

Here are a few more videos, now with the engine running much slower:

https://m.youtube.com/watch?v=o39i0Iiu8 ... e=youtu.be
https://m.youtube.com/watch?feature=you ... fFxr1YgfFs
https://m.youtube.com/watch?feature=you ... 0FE4EwSQ9Q

Any ideas?

Icarus

[schrader7032]

I guess I'm not sure what noise you're referring to. In the last video I don't hear what you first posted, a "high pitched" sound. Have you been able to "echo locate" the sound...what part of the engine does it seem to be loudest in?

[baddean]

Icarus,
The noise can clearly be heard in the first two of the three vids you posted together. It probably goes up in pitch the higher you rev the engine.
Have you checked the brushes and brush carriers in the generator? It sounds like a "soft" whine as opposed to a hard, grating metal on metal squeal.
A trick I, and probably others here, use is to use a long wooden handled screwdriver as a stethoscope to probe around the hot engine to locate sounds. The wooden handle held to your ear transmits sound very well. Hold the driver end against whatever you are trying to listen to.
I'd start up front around the generator area.
Hope this helps some,
Dean

[312Icarus]

I've used a real mechanics stethoscope and can't pinpoint the noise. It is indeed a higher pitched noise that heard with a helmet on with the visor up sounds like a howl. I think it is going back to the guy who did the slingers for me and we will tear it down, unless folks here can come up with a more definitive diagnosis to chase.

I too thought it might be the generator, but that is not where the noise is coming from. I also though it might be in the magneto, but what can make noise in a magneto? (Nothing that I can think of!). I did blow all the components under the timing cover out with compressed air just in case something was in the way.

thanks for the advice, look forward to hearing some more...

Icarus

[312Icarus]

I guess I'm not sure what noise you're referring to. In the last video I don't hear what you first posted, a "high pitched" sound. Have you been able to "echo locate" the sound...what part of the engine does it seem to be loudest in?

It sounds loudest at the top (cam area) but I can't ID it as a cam bearing. It still could be in the clutch, or maybe the timing gear?

Icarus

[312Icarus]

So..let's talk about generator noise. Where (and how) can the generator make noise? There are no bearings, the only point(s) of contact are the brushes. The commutator is clean, the brushes and springs are new. (That said, the bike doesn't charge properly, although recent testing shows the generator out put is fine). I'll test again to see if it is putting out properly and spray the commentator with contact cleaner and report back.

Thanks one and all for your opinon(s), keep those good ideas coming.

Icarus

[Daves79x]

Vech told me in one of our many conversations that the rear main seal is how the crankcase sucks in air, to then be expelled by the breather plate. He said that sometimes this 'sucking' sound is very audible. Just throwing that out there.

Dave

[312Icarus]

I may have come a bit closer to finding the issue. It may (I stress may) be coming from the clutch release rod. Pulling partially in on the clutch (or drawing in the bolt) seems to mostly eliminate the noise. Contrary to my intuition, it would seem that if you completly release the rod the noise should go away. So, I still don't really have a clue.

The next question is, can you remove the clutch rod without removing the transmission. If I am convince the noise is really the clutch, I will probably ride it for the rest of the summer (which for me is two more weeks as I'm going away at that time for a couple of months) and then will tackle it then.

Sound like a plan?

Icarus