Sprocket replacement for new chain or not ? Comp sprocket is affordable , clutch shell not so much . HD manual no tech on replacing the primary sprocket on clutch shell , teeth look good and top of tooth flat not pointy. 98,000 miles any advice thank you

 

Sprockets and chains can wear together, replace just the chain it can jump teeth on a worn sprocket. At least that my experience with drive chains, not positive about primaries. Check the dip between teeth, are they worn evenly? With that many miles I would replace both sprockets. But then again, where do stop? Whole new clutch?

 

How many miles on the sprockets? If they are not too worn you can get away with reusing them. Primary sprockets dont wear as much as rear sprockets that are open to the dirt and dust that make a nice grinding paste.

 

What year and model bike?

 

Perfect world change it all, budget world put the chain on and hope it wears in.

 

Chain will exhibit "stretch" as it ages - this results in a longer pitch as the chain wears. Overall chain grows longer, with more play in the pins and bushings holding links together.

With the chain "longer", and not matching the sprocket tooth pitch, the sprockets then wear into a "shark tooth" pattern as the chain abrades the side of the teeth bearing surfaces. This affects larger sprockets more, since the tooth count is greater and more chain length wraps the sprocket before it's released on the slack side.

Ultimately, with completely worn chain and sprockets, as the chain starts wrapping the drive sprocket on the tension side, it will start climbing up the side of the teeth, and with the wrapped chain under tension it could end up with a pin/bushing on the tip of a tooth as they try to mesh. I've never encountered this on heavy chain, as with HD primaries, but it happens frequently with bicycle chain if not maintained/replaced.

With only 98k on your bike, I'd guess your sprockets aren't worn beyond useful life. A new chain might age faster on the old sprockets, but they should work together fine. Try the new chain first, and then you'll know soon enough if you need sprockets.

Like Mark said, ideal fix is to replace both chain and sprockets...

Hope this helps,
John

 

What John says is right on.. The old adage about replacing all the sprockets is typically due to riders completely ignoring the chain.. The chain is worn way past shot and it takes the sprockets out.. You can get a good idea as to the condition of the chain by trying to lift it off the sprocket.. More than 1/2 the height of the tooth and it should be replaced.. I tend to do primary chains at about 1/3 tooth to ensure that the teeth stay healthy. Also external sprockets like rear drive chains live a more abrasive environment which can kill them..

I have a old XR400 that has a number of miles on it and with proper chain care the rear sprocket (aluminum) wore out before the chain did.. I replaced the sprocket and kept the original chain something like 2 seasons ago..

 

When I upgraded my bike a few years ago, the tips of the comp teeth were sharp and the clutch teeth were fine - there are more of them, so they share the wear better than the comp. So check your teeth, if they are sharp change accordingly, plus a chain.

 

If you can see any asymmetry to the teeth on any sprocket. Replace it..

 

True - although on this occasion I almost cut my finger on the teeth, which grabbed my attention!