This is regarding a '94 Dyna Convertible with 44,000 miles on it.

For a while now I've noticed a very intermittent but fairly loud kind of grinding noise that seems to be coming from the primary. It usually isn't there, but other times I'll hear it and it's always when the engine is idling, never any other time. It's been going on for around 800 miles. Hasn't gotten worse or any more frequent. Took the primary apart and found nothing wrong with the comp or clutch, chain, chain adjuster etc. and there were no metal shavings/chips in the oil or on the magnetic plug or anywhere else. When I turned the tranny shaft, it was silky smooth and had no cross-ways slack or looseness.

Is this a common symptom of an inner primary bearing going south? I've had shovels with dry primaries that had the bearings get noisy, but they always made a constant noise that didn't come and go, but the noise I'm hearing occasionally sounds a lot like that. I'd say that I notice the noise maybe once every 300-400 miles, and it always stops shortly after I hear it.

I don't want to pull the inner primary case if I don't need to, so any help, info, opinions would be VERY much appreciated!

 

Get a mechanic's stethoscope and poke around on the primary when it's making the noise. Try to find exactly where it's coming from.

I've had inner primary bearings go out back in shovelhead dazes. Seems like it made a noise all the time and ate the seal right next to it, leading to a leak right there.

Is your chain adjusted properly per the book and at the tightest part of the chain? You don't have one of those automatic tensioner things, do you?

 

Yep, chain is dead-on the 5/8" (cold) spec at the tightest point and I do not have an auto-adjuster. Bike is bone-stock as it left the factory.

I never get a chance to listen thru a stethoscope because it only makes the noise rarely and it's always gone when I get home. It never makes it on startup or shutdown. The only time I ever hear it is at a light or something like that. Engine is always at op temp.

Yeah, I've had to replace that bearing on every shovel I ever owned. I got a really nice '80 Superglide super-cheap once because the seller thought the tranny was gone when it was only the inner primary bearing making noise.

 

if the bearing is the issue, pull that race off the tranny shaft and replace the bearing with a sealed one

 

Do you have the clutch in when it makes the noise?? If so try poping it in neutral and let the clutch out. If the clutch is stock it may have a spring disc in it and when they start going they make some strange noises. Hope this helps.

 

The clutch is stock and does have a spring disc, but if I remember right the clutch has always been out with the bike in neutral and not moving, and I've only heard it with the engine at idle speed.

I know that inner primary bearing failures became common for a while when they went to the 6 speed trannys with the TC's, but I've never seen any mention of it happening much with the 5 speed EVO's.