XS650 Squeal Diagnosis

[patk12345]

I have a 79' XS650, that has a horrendous high pitched whirring squeal in the engine.

A few years ago when I was even greener to motorcycles and more importantly motorcycle mechanical work than I am today, I was trying to adjust my carbs for the first time, using the ever so unreliable Hanes manual. I followed all the steps to the letter, and the bike sounded great. The next day when I attempted to start the bike, no go, the plugs were fouled. I changed them out, and after a little coaxing, the bike fired up.

However, it now had a fairly high pitched squealing/ whirring sound. The sound increases in pitch as the engine is revved. Based on the resistance of the kick starter it still seems to have good compression. It drives fine, although I've only taken it on short test drives in order to try to diagnose the problem.
I've fired the bike up for various friends who are fairly experienced in the mechanical arts, but no one has been able to come up with a diagnosis.

It's been sitting for a long time as I assume it's well beyond my abilities, but I figured at the very least I would throw it out there for all of your consideration and collective know-how.

Thanks in advance!

[XSTrey11]

I've had exactly that noise come from my XS11G. No idea what it is though but it does get louder as the bike revs and goes completely away when at idle.

[3Phase]

I have a 79' XS650, that has a horrendous high pitched whirring squeal in the engine.

Pat, maybe the starter is sticking?

[patk12345]

@Trey- With mine it doesn't go away at idle. If it's on it's squealing.

@Scott- Interesting, how would one go about verifying a stuck starter?

[3Phase]

@Trey- With mine it doesn't go away at idle. If it's on it's squealing.

@Scott- Interesting, how would one go about verifying a stuck starter?

Good question, Pat. It would depend on what is 'stuck': the starter electrical circuit or the actual mechanical part of the starter/gears/springs.

Assuming the engine doesn't crank over and start as soon as you turn on the ignition, if a sticky starter solenoid is keeping the starter motor engaged then removing the wire from the solenoid to the starter and using the kicker to start the engine would stop the noise.

If it's a mechanical problem you would have to dig into the engine. There's a little more information about it at "XS650.com: Starter makes scratching noise"
but I can't hear the noise you're hearing from here so it's hard to hear where the noise is coming from.

[mr_misfit138]

I'm a greenie too, so I wouldn't hold anything I throw out there in very high regard, but I'd like to see what others that actually know what they're doing say. That way I can learn from this too!

What about bearings in the crank case? I always hear that bearings hate gas in the oil... and SeaFoam. I've never heard exactly what the exact aftermath is, but I've heard that gas in the oil can be pretty common, especailly if the carbs were recently adjusted.

Like I said, I could be, and likely am way off, but it seems like it could be a bearing if it speeds up with the RPMs. I'm sure someone else will kick in with more info though, and we can both learn from it!

[3Phase]

it seems like it could be a bearing if it speeds up with the RPMs.

It could be a bearing but it could be a loose cam chain tensioner.

Always check the simple things first.

I mean, it's not as though I was ever green and did anything like ripping up a perfectly good engine because I heard a noise -- nope, not me! No way Hose A!