High Pitched Mystery Sound

You sir are a genius. I've decided to take the thing apart anyway just cause I got it so stripped down, may as well replace the 5th gear etc. I'm working all weekend but can't WAIT to test for movement on the crank and then get this thing apart

Dave

Sounds like transmission whine to me, the excess (yes, pun intended) free play on the output shaft makes me think under actual riding load, the shaft is moving between the bearings and bringing the gears out of line ie: wear marks aren't lining up

time to open 'er up and do the bottom end

Awe well, have fun! Just replace/repair as much as possible. There's never time to do it right, but always time to do it again

So would transmission whine be a problem with the bearings or with other parts?

I've had problems with gear noise in a few cars. Trans- will likely change according to what gear it is in. Does it make more noise in one than the rest? If it happens only in one (2nd or 3rd -city cruising- or 5th -highway cruising-), that gearset ( the corresponding gears on the input and output shafts) could be excessively worn. If bearing(s) it should happen regardless of what gear it's in.

Hope that helps!

Also if it's the drive chain, it would be there no matter what gear and consistently increase pitch with speed.

It definitely is there regardless of gear and doesn't change when I shift gears. And it doesn't increase w speed but rather with RPM but only when the rear wheel is under load. When it's in idle, or when the rear wheel is lifted off the ground, no whine.

So I'm chasing a god awful whine that developed quickly last night and was wondering what happened here?

Probably not the noise your hearing but I chased a noise for a couple weeks. Ended up being my damn POS gas cap rattling at certain RPMs. Sometimes we overlook the simplest things.

Last night the bike was running fine then a whine started and quickly got worse I was lucky to make it home. Whine was quite a bit louder than the exhaust
cam chain was in adjustment. no filings in the alternator. Oil and filters had a few non magnetic filings more than makes me happy but not a big pile.
Pulled the plugs looked in side with a boroscope (compression is still good both sides) nothing of note in there. Pulled the clutch cover no big "there it is" moments.
Cranked it over with the e start and saw this.


I tried wiggling the crank end up and down with a screw driver no slop I could feel.
Any ideas what this means?

Are there bearings on those shafts? I can't imagine the crank warped? I would think a piston rod would fail before the crank?

Hmm that don't look right.

gggGary said:

Any ideas what this means?

Click to expand...

You're obviously going to have to split the case to fix it, and I bet that would also tell you what the problem is

A great mechanic with decades of experience on these said one thing they can develop is pitted crank bearings, which causes a whine. You've obviously got something come loose in there though.

Oh GAWD! Flywheel(s) tweaked on the crankpin(s)!!! There goes all the crank bearings. Hopefully the case bearing journal recesses aren't damaged.

Would love to see post-mortem pics of the crank...

That's some scary looking crank Gary

Yeah It's got to come apart, I want to keep this bike numbers matching. I guess I am unclear I thought the pins are splined I know you can twist a harley crank because the pins are just tapered but I though these things were all splined so that the crank can "spread" but not twist? This went from quiet smooth runner to OMG it's going to grenade in two miles with no obvious cause, no high revs or hard acceleration even. Shows 21K, It had been sitting a long (but unknown) time when I bought it but had reasonable looking oil inside. Oil was a bit dark and bit low I drained 1 3/4 quarts. Bike was in garage kept if a bit bastardized condition when I got it. This was the engine that had carbon under an exhaust valve seat and zero compression on that side. It was using a bit of oil maybe a quart a 1000 I had figured maybe a valve guide or seals the bores still have cross hatching ont the sides. I have put a couple of thousand on it over the last two summers. Last week I would have headed to California on it and not been worried. I thought I was detecting a bit of pre-ignition rattle intermittently a few miles before the big noise started.











Pamco high energy spark I think the left plug shows that was the cylinder burning a bit of oil (no smoke). Spark advance had been adjusted, it was moving smooth and at the marks high and low.

Oh yeah, that's not good news Gary. A crank that wobbles in the middle

Oh well, Gary, you probably were wondering what to do with your spare time this winter

Hey guys! It's Dave, the original poster of this crazy long thread. I have good news and bad news. Several months ago I committed to tearing down the engine to rebuild the bottom end to try to address this squeal, which I thought was coming from the bearings. I tore it down, inspected and/or replaced most everything in the hopes that I'd fix the squeal. The good news is that I now know how to rebuild the bottom end of this bike. The bad news is that I put it together, put in some oil, popped in some gas and started her up, she runs strong and sounds pretty...until I put it under load, in which case the squeal is back just the same as before. Sigh. I have determined that the noise comes from some manner of sorcery, or possibly a voodoo curse.

Hey Dave! Good to hear from you again, man!

This is an extraordinarily amazing adventure, voodoo curse. I just spent the whole evening re-reading all your threads/posts on this thing, back up to speed now. You've fixed at least a half-dozen genuine problems, and probably renewed many parts needing replacement, yet the original mystery remains, fascinating.

The good news is that you've addressed actual problem/failing areas, and have been thru the pits of demon hell (engine guts), so that now you've graduated to a higher level of understanding. Don't consider this as a waste of time/effort, sometimes the goddess of motorcycles does this to us so we'll avoid a bigger disaster later.

Now, down to the whine, still thinking about it being confined to the primary area, and that 10-20 'tinks' per revolution, and you've replaced a known/faulty right side ball bearing, we're left with:

1 - Primary drive gear lash. You mentioned replacing your `79 basket with an `81 basket. Although all this should be interchangeable, that article on gear lash does raise an issue. Could also check for tiny nicks/spurs on the gearteeth of both gears.

2 - I don't recall any basket spin test (you spun-test the hub, not the basket). Gotta pull the primary crank gear to be able to freely spin the basket. Looking for wobble/runout/sounds, anything unusual.

3 - Electric start gearing, a known problem area. On one of your old (April, I think) pics of the open right side, can't quite make out if the hairpin drag clip is properly positioned.

4 - Double-row transmission input shaft bearing, behind the clutch. Ignore this if you've replaced it. During the load application, the crank output primary will be loaded downwards. You resolved this by replacing that crank ball bearing. However, the clutch basket will be loaded upward, and what keeps it from displacing is the sleeve bushing and that double-row ball bearing. Any displacement here will open-up the primary drive spur gear spacing, and induce a sound as described in that gear-spacing article. Could try firmly grasping the clutch, or just the shaft, and try to force movement up/down, like checking ball joints on your car.

5 - Sleeve bushing and basket inner race clearance - As in #4 above, excessive clearance here can open-up the primary gear spacing.

Fortunately, all this checking is just inside the right side cover. How many times has THAT been off?

Edit: For folks who may be trying to follow this thread, the saga split off to other threads.
The main split-off is in here, where Dave is replacing the crank's right side ball bearing:

http://www.xs650.com/forum/showthread.php?t=27453

Heya Twomany! Hope you had a great summer! Thanks for taking the time to look at this thread and give me your thoughts I have a bit more info, which is that I took it out today for a short run and actually, the squeal is MUCH less than it was before. In fact, it's only really noticeable in first gear and then pretty much goes away, which is a nice change. Does that point to one of the options you listed above do you think? Again thanks for the time and thought

Dave