Rear sprocket mod

Just buy a Dominator gearbox sprocket and, if you are lucky enough to have an early bolt up rear drum, a dommie rear drum. The dommie rear drum has different sleeve nuts (BSF or Cycle can't remember which) 520 O ring chain and away you go. (There will be someone along in a minute to talk about the increased drag of an O ring chain)

Can't see what all the fuss is about regarding O ring chains & sprockets., Scotoilers etc unless you go riding in extreme conditions, which I'm sure most of us do not. The chain is a wear item so just get a good quality IWIS one from Andy The Chainman for £35 and fit a new one every year/5K miles - occasional lube & clean required - sprockets seem to be hard wearing.

I've heard good things about Iwis chains and the chain man, mostly from his own posts on the Access Norton forum. If however you consider chains to be shagged out in one year or 5000miles, you've probably got a bit too much money floating about. I suggest you throw your tyres away when they are only half worn as well. The reason for fitting an o ring chain in my case was to reduce the amount of grease fling and allow me to spend less time cleaning up the mess and more time riding.

I have a 520 conversion and my reasoning was twofold, less wear and less mess. At the time I had not heard of the 'everlasting' Iwis chain and I would have tried it since I do lube my chain quite often (but not every ride unless its been on a very wet one prior). The DID 520 'O' ring I fitted several years ago has needs adjustment once a year or 3000 + miles. So called 530 heavy duties were every 3 or 4 hundred. I'm sure the Iwis is good but I got very fed up with the self promotion of the dealer on the Access Norton site and his view that not enough Commando owners were buying his chains........oh and O rings rob a lot of power. Some yes but not the 5-6 hp.I believe was claimed. On that basis, big sports bikes of 20 years ago would have been losing 12-15 hp through the chain alone, prior to X rings coming on the scene. I do accept I have had to replace my gearbox sprocket recently (appx 12,000 miles on 520 and 30,000 total) but that was a cut down 3/8" with crude surface hardening. I fitted a 1/4" Dommie pattern as replacement.

Previously K Glassborow wrote:

I have a 520 conversion and my reasoning was twofold, less wear and less mess. At the time I had not heard of the 'everlasting' Iwis chain and I would have tried it since I do lube my chain quite often (but not every ride unless its been on a very wet one prior). The DID 520 'O' ring I fitted several years ago has needs adjustment once a year or 3000 + miles. So called 530 heavy duties were every 3 or 4 hundred. I'm sure the Iwis is good but I got very fed up with the self promotion of the dealer on the Access Norton site and his view that not enough Commando owners were buying his chains........oh and O rings rob a lot of power. Some yes but not the 5-6 hp.I believe was claimed. On that basis, big sports bikes of 20 years ago would have been losing 12-15 hp through the chain alone, prior to X rings coming on the scene. I do accept I have had to replace my gearbox sprocket recently (appx 12,000 miles on 520 and 30,000 total) but that was a cut down 3/8" with crude surface hardening. I fitted a 1/4" Dommie pattern as replacement.

Chanins are one of the most efficient of power drives provided they are clean, adjustewd and lubricated but chains inneed of adjustment or lube lose a lot of power anyway. So power loss will only be the difference between this and an O ring, the O ring might come out on topin this situation. I read many years ago that a Manx at the end of a race in the Island lost about 25% of its power due to the state of the chain,but then I don't suppose many of us ride that quickly for so long anymore.