Hitchcocks Forum

Hi chaps

This may have been asked before, in which case, humble apologies!

I'm building up a 350 based on a 1992 Superstar. BW has ported my cylinder head (nice job too!) and I was going to fit a 28mm Mikcarb, but it won't fit (top of carb fouls the rear tank/head steady fixing & frame). I have an almost new CV carb originally fitted to my ElectraX, which does fit...!

Question is where to start with jetting?

Key features are 350 standard spec apart from:

- ported head (30mm inlet)

- modest compression of around 8:1

- k&n filter (or similar)

- freer than standard exhaust, but not an open megga!

- electronic ignition (Boyer mk4)

Any help & suggestions gratefully accepted!

Thanks

Stephen

I would not bother. Aside from it being tuned for economy with a different design of combustion chamber and compression ratio, the CV carb is not conducive to 'performance'.


One of the newer Mk1 amals will prove easier to tune, it will have better acceleration and top end flow, and has a full range of jets available.

Alternatively, and it would cost you nothing, you could fit your Electra X CV carb with its standard jetting and see how the tuned 350 runs with those jets. If changes need to be made you could adjust jetting according to the results you get with the standard jets.

To fit the Mikarb, purchase a rubber manifold for the earlier '90's bullets. This is shorter and the carb plugs straight in. This moves the carb forward away from the tank. The only thing I'm not sure of is if the mounting studs on the head are different between 350 & 500, because you would need the 500 one to suit the 28mm carb. Or you may be able to open out a 350 one if the mounting is different.

I was going to fit a 28mm Amal concentric I have but decided not to. It has an alloy manifold to fit the 500 too, plus cables. I wiil probably have to put it on e bay or somewhere as it is sitting in a box in my garage unwanted.