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Discussion Starter · #1 · (Edited)
Looking for a little advice... but I have a feeling the answer will be: "take it in to have a service tech check it out". Also, did a search, but didn't really find anything that described just what I'm experiencing.

Just did a sprocket/chain swap. DID ERV3 gold + geared down to a 14T front (from the stock 15T). The chain is properly adjusted (never overtightened) and the rear wheel/sprocket have been laser aligned. I also just installed a Desmo Times Case Saver and Billet Rear Axel Plates, put on a new SpeedyMoto Front Sprocket Cover.

Over the last few days I have noticed a strange harmonic whine coming from the left side. Somewhere near my left foot, so between the output shaft/front sprocket to the rear wheel/sprocket. It only becomes apparent at speed (usually 35+) and only after the bike has warmed up a bit or I've ridden 10-15 miles.

I initially feared the chain might be making contact with the case saver, but I took it all apart and no signs of any contact. Checked for obvious play in the output shaft (crank) and couldn't feel anything. In neutral I could spin it and I don't feel anything rough with the bearings. Some ever-so-slight lateral play on the front sprocket, but nothing out of the ordinary for the Ducati fixing plate system IMO. No abnormal wear on the sprocket itself.

I then I thought rear wheel bearings. Took the chain off and the wheel spins pretty freely. No rough spots detected there, either. No play in the wheel (that I could feel, at least). Also no signs of abnormal wear on the rear sprocket.

I just can't figure out what's making this noise. Very hard to pinpoint an exact source while riding the bike, too. Again, sort of a harmonic "whine" at speed. Gets more prevalent the faster I go.

Maybe the new chain rolling on the chain guide, now that the front sprocket has been reduced 1-tooth (putting it slightly closer to the swingarm)? A bearing that is starting to go bad, but not bad enough to feel just yet? I just don't know what else to check & I'm a little worried.

Does this sound familiar to anyone?

Any advise on my next step(s)?
 

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Is your chain too tight? On my 1000s the chain has 61 to 63 mm of slack from the bottom of the swing arm to the top of the chain thats over 2 inches. You should have diagram on the swing arm if not give your dealer a call for spec's. I know you mentioned the chains adjusted properly but sounds more like too tight.
 

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Discussion Starter · #3 · (Edited)
Yeah, I think you're probably right.

Manual says 20-25mm.

For some reason, my brain is recalling 30-35mm on the decal on the bike (but I can't be sure right now).

Whatever it says, though, I will definately give it a check when I get home, loosen it up a bit and see what happens.

Someone on the "other" monster forum asked about ride height and if I'd raised the rear. I have... which could be addind to this issue: I've been checking while the bike's been on the rear stand... without the weight of the rider. So when I'm sitting on the raised bike, it takes some travel to get the driveline to it's tightest point. What seems adjusted properly on the side or wheel stand, could be too tight under my weight.
 

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Yeah, I think you're probably right.

Manual says 20-25mm.

For some reason, my brain is recalling 30-35mm on the decal on the bike (but I can't be sure right now).

Whatever it says, though, I will definately give it a check when I get home, loosen it up a bit and see what happens.

Someone on the "other" monster forum asked about ride height and if I'd raised the rear. I have... which could be addind to this issue: I've been checking while the bike's been on the rear stand... without the weight of the rider. So when I'm sitting on the raised bike, it takes some travel to get the driveline to it's tightest point. What seems adjusted properly on the side or wheel stand, could be too tight under my weight.
Sounds like the chain alright. If you've raised the rear ride height you need to compensate by increasing the chain slack a bit. Try getting someone to check the chain slack while you sit on the bike and bounce.

The chain will be at its tightest when the front sprocket shaft, swingarm pivot and rear axle are in a straight line. Occasioanly if I'm feeling really pedantic, I'll unbolt the shock and get all three points in line, then adjust the chain.
 

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Discussion Starter · #5 ·
Haven't had a chance to do a ride & confirm 100%... but right now i'm pretty confident it was the chain.

I managed to hop up on the bike (VERY carefully) while up on the rear wheel stand & reach down to check the chain while my weight was compressing the suspension. It was tight as a guitar string!

I loosened everything up again and adjusted again, checking the slack while compressed. Looks like it's set up right now, 20-25mm slack with me on it. WheN I'm not, it looks really loose. 2-2 1/2 inches.

Now I hope I didn't hurt anything too bad riding to work & back Thursday (about 30 miles round trip).
 
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