Duplex Primary Chain

[G-Man]

Although it is possible again to get primary chains in the UK, at least, I thought I would try a duplex conversion for my CYB bike. I stripped the sprocket off a clutch a little while back while I was looking fopr suitable clutches for my 1961 biks so I though I might go ahead and complete the mod. You can get complete duplex conversions from Cappelini but mine came for Moore Performance Engineering in the UK. http://www.mpe07.co.uk/mpeprod2.html

The kit comes complete with new sprockets and a duplex chain as well as the screws to mount the new chainwheel and a spacer to fit at the back of the clutch to get chain alignment right.



First job is to get the plate off which covers the cush drive rubbers. The rivets can be ground off and then punched out.



With that done the plate slips off, revealing the cush-drive rubbers beneath.



The new sprocket will fit straight on over the cush rubbers but the bosses inside the rubbers must be tapped M5 to accept the screws and the cover plate needs drilling and countersinking to accept the screws.

I had to turn my cover plate down from 125mm to 120mm to fit in the recess in the sprocket. I don't know if this an error or deliberate. I will ask Ellis Moore.



With that done, it's a matter of screwing the parts together.



The crankshaft sprocket is a direct replacement but a little more work is required on the clutch hub as the 1.8mm spacer sets the hub out farther along the shaft. A corresponding 1.8mm must be shaved off the clutch hub to give clearance for the circlip.

All in all, just a couple of hours work in a well-equipped workshop for a better primary transmission.

G

[cknight]

Neat unit. Do you use the stock chain tensioner? Thanks, Chase

[G-Man]

Chase

MPE don't supply a new wheel but I notice that Cappelini do. Maybe that 's the difference in price between them. I think I am going to have to make a new wheel for the duplex chain. I'll report back.

G

[sjkowal]

Is someone in the UK making repro primary chains or is it still possible to find NOS chains there?

Although it is possible again to get primary chains in the UK

[LOUD MOUSE]

I just sold one on eBay and have others but not that price again. ...................lm

Is someone in the UK making repro primary chains or is it still possible to find NOS chains there?

Although it is possible again to get primary chains in the UK

[G-Man]

Yes - Sprockets Unlimited are making up the chains. I bought a couple at the Classic Bike Show at Stafford in April. http://www.sprocketsunlimited.com/

I bought some NOS chains from David Silver a year or so ago but haven't seen any for a while.

G

Is someone in the UK making repro primary chains or is it still possible to find NOS chains there?

Although it is possible again to get primary chains in the UK

[SMBH]

I can vouch for the sprocketsunlimeted chain it seems to work OK for me just stripped the side down after some 500 miles and the chain looks good, they are a great pair husband and wife (I think) for ALL your Honda chains they have been around many years on the British's autojumble scene and know there stuff.

Now I hope they send me the money.