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I pulled the counter shaft sprocket cover off my 74' CB 450 K7 to clean behind and help remove the drive chain. What I discovered is that the front sprocket seems loose to me ( side to side play ) when the 2-bolt retaining ring is bolted to the front of the sprocket to prevent it from coming off the shaft. The front sprocket is the "stock" Honda sprocket ( 450 S15 ) but shouldn't it not move at all ? I looked at the parts diagram and doesn't show a shim behind sprocket ?
 

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The front sprocket is a slip-fit on the shaft and there is naturally some looseness. The bolts and plate keep it from coming off the shaft and keep it in the proper area for chain alignment, but there's nothing behind the sprocket. Unless abnormally loose from wear on either the splines or the sprocket, it's normal
 

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Cheap and nasty method, should have been a positive fitment, large nut and lock tab etc..

For future reference, always lub the front sprocket splines well. Many a time I have come across well and truelly corroded on[/I] front sprockets, as if its "taboo" and a "crime" to lub stuff like chains, not to mention sprockets.

If the g/box output shaft sprocket splines are badly ( how bad is bad, sprocket mis alignment, on a "WOBBLY " system, which, to be fair, was not that wobbly when it left the factory ) worn, then a new one needed.

How is front sprocket teeth wear, and how wobbly is the rear sprocket system ?

New sprockets will have "new splines" but they will be riding on a worn shaft.

If the system throws the chain off, you know the consequence ?
 

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I have never seen a chain thrown off due to a sloppy front sprocket, nor have I ever seen a countershaft with significant wear that would warrant replacement - like the gears internally, it's of a harder steel than the sprocket. If anything would cause undue wear, it would be the constant hammering of drag racing and my used 4 speed bottom end had all the same parts in it for the roughly 3 years of twice a week drag racing I did in the early '70s, and never even had to change a front sprocket. He'll be fine.
 

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I'll post a picture of a badly worn ( corroded ) g/box output shaft splines for you. Its still on the bike from memory with a new front sprocket. The rear sprocket was considerably wobbly and needed "packing" so it would pass a mandatory safety check.

That bike did throw a chain but at very low speed ( 3mph ) whilst turning/leaning right. The chain was very slack, worn and out of adjustment at the time though.
 

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It's actually cheaper to do it Honda's way. Less machining on the countershaft and it does away with a lock tab that needs bent over on the assembly line. A bit of slack in the splines allows for some self-alignement of the chain if the wheels arent perfectly straight.
 

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A visual inspection will tell you if wear has taken place? The sprocket has to be a loose fit axially; but tight radially to allow for chain alignment. The design has worked well for years when properly lubed; so check the output shaft for wear; and if no wear carry on with a new sprocket and chain.
 
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