93 evo developing a whine

[gkal]

Noticed the whine last year, but this year it's getting pretty loud.
It seems to be coming from the lower front of the engine or primary.
The pitch varies with rpm. Battery is charging. No oil leaks.
I do get some oil in my stator plug. Could this be an alternator
problem, or a bearing? I've never run my primary chain tight.
It's always been within the required measurment, but toward
the slack end of the range. 49,000 miles. Otherwise she purrs.
gkal

[evoKENevo]

Welcome to the site,gkal

Engine noises suck. Because they "telegraph"...and,can be coming from a different area than they seem to be. Generally speaking, the weakest link in an EVO engine is the inner-cam bearing...which a new Torrington bearing would virtully eliminate. When it's "going-away" there's a whining/whirring sound that increases & decreases with RPM and can sound like it's coming from the other side.

Invest a few bucks in a mechanic's stethoscope...and,your noise will be much easier to locate. Meanwhile I would'nt be riding the bike. Because IF it is the cam-bearing (or anything else,actually) you could be looking at some SERIOUS-$$$ if/when it "lets go" on you.

Of course, it COULD be something else...but,based on what you're telling us here, this is the MOST-LIKELY cause/source of your noise...IMHO anyhow.

[gkal]

evoKENevo,
I have a stethoscope. Is there a particular place on the cam cover I should be listening to? I have been probing strictly on the primary side, and it seemed the loudest around the primary/engine block interface.
gkal

[evoKENevo]

gkal:
Try listening on the right side of eng-case..just behind and/or along side of the rear lifter block...avoiding ANY eng/trans/primary/etc. COVER that JUST "echos" and/or "amplifies"what's being "telegraphed" for MOST-PART anyhow.

[frisco-rigid]

Hey gkal ------ interface..??!! I like that term, I'm gonna use it somewhere..
OK
A lttle lube splashing up and seeping thru the Alt-plug hole is no big deal..

The Alt. rotor spins with the motor shaft around the Stator, there is nothing to cause a whine.. If there was contact tween the two you'd have known it quite Unpleasantly.. I've had it happen and it's immediate not on-going like your whine..

If the stethoscope reveals little or nothing over on the cam side I would drain the primary, take off the outer cover and run the motor while listening as closely to the left motor case as possible.. Even stick the probe right on the compensating unit nut.. Whatever you gotta do to zero in on that Left-crankcase Timken Bearing.. Depending on what you hear you might be able to narrow it down..
There is enough lube on the chain and sprockets to run safely so don't worry bout that at all..

If you're still not satisfied, listen over near the inner-primary Tranny main-shaft bearing..
I've never had a similar whine but these are the ways I'd search for it given your description of it..

[aceharleywrench]

At 49k I would be taking a close look at the lifters & the inner cam bearing.If these have never been changed its a good bet thats where your noise is coming from.