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#6468
Paul W
Participant

Hi Roger,

Many thanks for the list of items to check – really useful stuff.

For the record the compression ratio I quoted was calculated from the swept volume plus measured volume at tdc (approx 30cc per cylinder) divided by the measured volume at tdc. I now realise that this is quite misleading as the port timings (and the other factors you refer to) prevent a complete fill of the cylinders. Even so, by applying the same calculation to my other Scott engine this new one still has a relatively higher compression ratio.

I’m fairly confident that the flywheel and flywheel sprocket are sound. I will double check the clutch as i’ve had it apart several times trying to adjust for an even lift. One simple thing I will then try is to swap the NGK B6ES plugs for some cooler ones as the noise reduces when I richen the mixture. I’ll let you know how I get on but with these darker evenings approaching it’s getting more difficult to take the machine up and down the road during the week (no lights on the bike !!).

Cheers,

Paul