High Pitched Mystery Sound

[peanut]

its difficult to 'guess' what the issue might be when we cannot hear the sound for ourselves.
You are either going to have to bite the bullet and tear the engine down or get a recording of the noise .

Try attaching a small point n shoot camera to the bike with gaffa tape using plenty of foam or sponge to protect from vibration .make sure the camera's microphone is out of the direct slipstream .
Stick the camera on video and go for a run . you might get something useful.

Alternatively take the bike to a local workshop and get an expert opinion. They are unlikely to charge you to just ride the bike and listen.

 

[Paulrxs650]

XSLeo has it right.
Its your cam chain / guide make that noise. Usuall happens when the nylon guide wears away and it goes through to the alluminium backing / fasteners. Check your cam chain tension in the normal way. If thats ok, drop the oil and check for any nasties. Black nylon shows that the guide is wearing normally, alluminium or metal particles show that its worn through. In my opinion, I would have the head off and replace the guides.

 

[peanut]

I thought xsleo was talking about the drive chain not the cam chain ?

I think you are probably right though the cam chain guide does seem the likely culpret.
Many of our bikes don't have a lot of miles on them but rubber deteriorates in time and can lose its bond with the alu guide. I reckon my cam guide is the original fitted 33 years ago and still 'looks' like new

 

[Paulrxs650]

So he is! D'oh!
Apologies! - Its the cam chain I am referring to!

 

[peanut]

did the same thing last night myself. blush. RG soon picked me up on it bless him

Your build is certainly coming along pdq I think I'm going to pluck up the courage to put the engine cases together today and then my engine rebuild should go ok hopefully.

 

[Paulrxs650]

Thanks - go for it!

 

[davem222]

Alright guys, so I risked life and limb getting some audio of the sound lol. Here's two vids, one is of the engine while riding, and one is of the engine revving while in neutral. Note the high pitched noise is completely gone during neutral, which would lead me to believe it's not the cam chain, no? I mean, the cam chain is fully taut and engaged while in neutral when the engine's revving, right?

While Riding:

In Neutral Revving:

 

[rebel542]

You told XSLeo the noise went away when you rolled off the throttle and coasted. True? If so, you could have badly worn or improperly adjusted chain and or sprockets.

 

[rebel542]

Just looked and listened to vid. Sounds like chain to me.

 

[davem222]

Cam chain or drive chain? If its cam chain then why doesn't the sound happen when revving in neutral?

Posted via Mobile

 

[rebel542]

Drive chain probably to tight and under lubed. Cam chain sounds ok. Sorry I didn't specify which earlier. Hope this helps.

 

[davem222]

Thanks. Helps a LOT. Gonna lube it and loosen it (that sounds kinda gross) and see. Thanks

Posted via Mobile

 

[XSLeo]

I listened to the vids. In the first the engine sounds good, I can hear a bit of noise and it sounds like drive chain noise.
In the second the engine sounds very good.
Your drive chain should have about 5/8 to 3/4 play when it's on it's wheels and you sitting on it.
Just reach down and pull the chain up, it should move about 5/8 to 3/4 inch. move the bike about a foot forward and check again, do this several times looking for the tight spot. Once you find the tight spot adjust the rear wheel to get the 5/8 to 3/4 spec. If you do this at a loose spot it can be too tight at the tight spot.
Also while your checking the chain check for wear on the chain and sprockets by trying to pull the chain away from the rear sprocket. If you can pull it away more than about 1/2 a tooth away the chain and sprockets are worn. Replace as a set.
I like the Xring chains, the X style seal between the sideplates and rollers keeps the lube installed at the factory in and water and other srap out. The O ring chains can let the lube out and crap in. O ring is better than regular chain the X ring even better.
If you keep the regular chain properly maintained it will serve you well.
The O ring and X ring chains don't need quite as much maintainance.
I like the 17 F 32 R combo on the sprockets. A bit better highway cruise but still good around town performance.
One more thing, on the front sprocket the nut can come loose, many are found that way even with the lock washer bent up.
Leo

 

[davem222]

Thanks Leo, here's the weird thing: so I lubed the chain and got the slack right, also the sprockets don't seem worn at all. The noise is still there and what's more, the sound starts to ramp up as I engage the clutch and continues in proportion to how much the clutch is engaged. I'm wondering if perhaps when I rebuilt the clutch I did something terribly wrong. I don't think so as I did everything to the letter, but perhaps I'll go back in (UG) and disassemble it and reassemble it. Maybe I put in a washer backwards or something and now there's some rubbing? I don't know. If you have any thoughts on why it might give a noise like that from the clutch, I'm all ears. Thanks guys!

Dave

 

[davem222]

Oh, and lest I forget, the thing that tipped me off that it's not the drive chain (or at least I don't think it is) is that a) I lubed it and loosened it b) the sprockets aren't worn and mostly c) even when stopped at a light, when I engage the clutch and pull the throttle, the noise starts as the clutch engages with the slightly revving engine and grows proportionally to the engine rev NOT the speed of the wheels. Tis truly a mystery.

 

[peanut]

well that sounds like you've located the source of the rubbing noise dave ... well done.

You are probably going to have to bite the bullet and remove that cover

See if you can find a clear exploded view of all the parts to help check correct assembly.

 

[davem222]

Peanut, aside from being a delicious and salty snack treat, I believe you are correct. Isn't there something wrong with the manual and the fiche on the clutch? Mine's off an 80 I believe, but isn't there like a washer missing from the fiche or something?

Dave

 

[XSLeo]

yes, most books and part fiches show only one thrust washer with the needle thrust bearing. There should be one washer on each side of the bearing. One has a large center hole that fits oever the bushing that goes into the hub and one with a smaller center hole that fit the input shaft of the transmission.
Most have the right parts unless a PO has been in there and left one out.
Leo

 

[peanut]

it wouldn't surprise me but I am not aware of it .
You need someone with a late bike and mine is a 79 .
Have you taken that cover off yet ? you know you've got to

Good opportunity to check and change your oil too

There ya go ! I knew leo or someone would be along to confirm it

 

[davem222]

Hey guys,
So I'm still baffled as to what is making this sound. I did discover that I was missing the thrust washer missing from the clutch diagram but it didn't help, the noise is still there. I'm 10000% positive that the clutch is assembled correctly, lol, I did it 5 separate times at this point. So I don't really know what to do. Again, the thing that baffles me is that it's in proportion to the engine revs (not speed or I'd think it was the wheels or chain maybe)as soon as I engage the clutch. I did remove the starter motor, could it be something going on over there? I also now am having odd trouble with my kick starter. It used to be really resistive and start on one kick. Now it feels much softer and takes several kicks. The odd thing is I never touched the starter and the only thing I can imagine that made a difference is that now I have that extra thrust washer in, would that matter? Ha ha ha, this is certainly a puzzle. Anyone have any thoughts?