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Drive chain noise/grinding _ New chain and f/r sprockets

MightyZeusAk

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Got a bit of an interesting one for the crew.

Changed f/r sprockets and chain ~ 600 miles ago on my '96 Nighthawk 750. Used good quality parts ~ only had an issue crimping the master link, but clearance was equal/sufficient in the end.

The issue is that there is a cyclic noise/grind. The cycle of the sound is directly related to final drive (i.e. gear independent). It's definitely related to chain revolution based on the frequency. But the chain looks good, the sprockets look good. What am I missing?!

I'll try and get a sound bite after I finish up the clutch replacement this weekend, but the best way to describe it is that it sounds like a few links (~4-5) are grinding as that portion of chain moves through the front housing.

There doesn't seem to be much physical displacement (i.e. the bike doesn't slow/choke) as the sound is made.

Any ideas at all would be great. I am not a hardcore bike mechanic, but I understand most things.

:shrug:
 
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A sprocket with the OD machined out of concentric with its' center hole. Or heaven forbid a bent output shaft. If it didn't do it before then sprocket. Usually the rear, it can get out of shape worse when they make it, the fronts by virtue of the small size are harder to get out of whack, but the noise ends up there because of the smaller turn radius. You should be able to get the rear wheel in the air to spin then set the chain a bit too tight and slowly roll the wheel to find a tight spot and the issue. If the bolt holes have enough slop you may be able to reposition just barely to make it better, I've redrilled say a couple holes slightly bigger to address one before. Depends on how tight your center pilot hole is.

Of course, you CAN adjust the chain too tight to begin with to get there somewhat anyway, the chain must factor in the suspension angle/distance change when you put your weight on the bike. You have to adjust with that in mind.

Never seen a new chain be bad, but in an era of all quality going out the window to service China anything is possible. The good quality parts thing? One likes to think but with all the world class brand names now being bought to make the true parts in China one never knows any longer. When faced with a problem I personally have learned to suspect everything, it makes every day less boring.

If the common chain size of 530 is used there then there can be sprockets or chain very close to that like 520, 525, along with the 530 width but they likely should not even fit parts together or be too loose. All the same length of link, just the width changes there.
 
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Thank you for the tips, I'll be checking that out accordingly.

I know what you mean about the quality thing. It's sad. Especially in the world of things such as motorcycles where it's so important. I've honestly got a shopping cart full of new sprockets and chain, just waiting anyway. Did that in the spirit of what you were saying about suspecting everything. Figured it's worth the peace of mind just to replace it all.

I'll let you know what I find.

Cheers.
 
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