Primary chain decision

A

Andy Mac

Full member
Hi all,

I am at a close to stage of the SFC1000 engine rebuild where I will be reassembling the primary drive.  I could just refit the original twin simplex chain arrangement (with new chains!) or I could use triplex sprocket and chainwheel (which I have) with a Merck duplex chain.

There have been lots of posts over the last 18 months regarding the qualities of the Merck duplex chain, but I suspect that many of these are from people switching from triplex chains (as they already have correct sprocket/chainwheel) and that would seem to be an obvious beneficial move.

Has anybody switched from twin simplex to duplex with a 120 engine and done enough distance with both to be able to make a decent comparison?  I plan to use the bike for long, fast trips (Alps in May - bike completion permitting - and Southern France in late summer).  I am sure the twin simplex set up would be fine, but could duplex be better for smoothness, quietness and longevity?

Regards, Andy 
 
Hi Andy,
Have changed a few 120 engines over to the Merc duplex.
I believe they make a difference, engine certainly sounds quiter and smoother with the duplex as opposed to the 2 x singles.
We change our race engines to the duplex as well, don't run singles on them and the triplex robs too much power.

I just bought 5 sets of primary chain sprockets from Wolfgang as I am running out of triplex used sprockets.
Red
 
Thanks for your comments, Red

I am very tempted by the Merc chain so I shall probably now order one.  Inner or outer position has been asked before, I think; I would be inclined to use the inner one to keep the chain weight inboard, but I guess it does not actually matter that much? 

Now who sells chains.......

Just re-read my post and saw that that Merc now reads Merck (with a k in case it does it again), which I definitely did not write - spooky.  I didn't think this forum corrected words unless spell checked and changes were accepted?

Cheers, Andy
 
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