Commando Drive Chain

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Jun 9, 2004
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I have recently purchased a new Renold Motorcycle Chain for my Norton Commando 850 MK2A Interstate. The problem i'm having is that the chain is hard to adjust to keep the correct amount of tension, it is either tight or slack when checked in different positions around the chain. I have put this down to a worn chain. I am not certain of the condition of the drive sprocket but have been told that when fitting a new chain it is advisable to change it. Can anyone advise me on this and what sort of task is it to change the sprocket if needbe.



You can't go wrong installing new sprockets with a new chain. A worn sprocket will wear the drive chain prematurely. However, most people do not change the sprockets when they install a new chain because of the effort and money. The drive transmission sprocket will show wear before the rear wheel sprocket, owing to its smaller size. So, an economical compromise would be to repalce the transmission sprocket with the chain.

Having said all that, it doesn't sound like you have sprocket problem. Instead, it sounds like your chain is rusty and stiff in some places and loose in others. You should be able to check this by looking. Also, you need to check how much wear you have in the chain.

First clean the chain thoroughly with gasoline and a brush. Let it dry and check the stretch, which is a good indicator of chain wear. To do this, compress the chain and measure its length. Then stretch the chain out and measure its extended length. The difference between the two measuremts should not exceed 2% of the chain length. For your chain this percentage is about 1-1/8". If your chain is stretched beyond this limit, it's time for a new one. And if your chain is worn to this extent after only a few thousand miles, then it sounds as if you need new sprockets.

Hope this helps,

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