750 valve springs

B

Basketcase

Senior member
By chance, I compared some S&W variable rate valve springs from a Jawa/ESO speedway 2 valve motor with the 750.

Same free length.

OD 35mm.

Laverda valve collar shoulders are too loose over the spring ends.

However, I happen to have some titanium Ford V8 collars that could be reduced to a snug fit but their collets suit 5/16 in or 8mm valves.

I don't suppose anyone has tried this setup for racing since 7mm stem valves are lighter.

Another problem is that S&W variable rate springs are no longer made.

Maybe they would be good for a road setup where initial seating pressure could be reduced in order to prolong cam & rocker life ?

Cheers,

Rob
 
Hi Rob - I used to have 750 valve springs made to suit the 5C and 6C cams - the std ones tend to give valve bounce too early with these profiles. I will probably get some more made this winter as I'll need them for my 860cc twin - I do have a set of titanium top collet retainers for the 7mm valves too! - regards - Phil
 
Hi Phil,

I might resist the temptation to try to make the world's fastest 750GT.

I was clearing out my old speedway parts from the shed and had a 'hey that's a great idea' moment.

These springs won't fit my Matchless G80CS so I think they might end up making a Jawa short circuit rider happy for a short time !

Cheers,

Rob

 
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