I've recently bought a 1994 MC28SE, in tidy condition, apart from its chain and sprockets.
Only managed 1 proper run out on it so far, and found it revving out in top gear.

No problem, I thought. It needs new sprockets/chain, I'll change the rear sprocket size, as I did on my R5K.
Checked previous posts on here for other members history of doing it. 38 or 40 tooth seemed favourite, down from 44 as standard.

Ordered 15/38 and a new chain, and fitted both sprockets today, but decided to check the chain run with the original chain fitted first, before shortening my new chain. My issue is, when the chain is fitted, it appears to run up/over the chain guide slightly, due to the smaller rear sprocket. Obviously, this means the chain runs tighter against the guide constantly. This also made me think that a 38 may be a bit too much for 1st gear getaways. Gave it a run, it needed no more revs/clutch than my other strokers to pull away.

Can anyone put my mind at rest, and clarify if the chain run is wrong, and I need at least a 40 to clear the swingarm guide?
Or that all is fine, and others are running the same setup?


Last edited by bobbyboy on Tue Dec 27, 2011 9:38 pm; edited 1 time in total

Unless you're planning on racing Snetterton (I think they have a massive straight), a 38T on the rear is much too low. I ran as low as 37T at various cicuits without any troubles on the chain guide/swing-arm.

You could sit on the bike and have a friend see if it still runs overs the chain guide. The top run usually pulls tighter when accelerating (or giving throttle).

I'm running a 15/40 for a larger circuit here in Japan and still have a little more and I'm at 160km/h. For the stop and go traffic, the previous owner had a 15/48.

Dana
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2016 Husqvarna 701SM
2021 Husqvarna FS450 supermoto
2014 Honda CRF250R supermoto
1995 NSR250r MC28