Hi all, could any of you A65L owners have a look if a metal spacer (manifold) is fitted between the cylinder head and carb the ones I have on are nearly 3/4inch long don't know if they should be there can't find any information. thanks Roy
Hi,
I have 2 A65's with tufnol not metal spacers. I have seen and used metal similar to these but they were not a standard feature:
http://accessories.hitchcocksmotorcycles.com/Amal-Carburettors/FINNED-ALLOY
Best wishes...
neither A65 Thunderbolts had them or the A50 RC. longer stacks are usually a tuning feature. the Lightning being the sportier version would probably have been a seperate after market tuning mod.
the Hitchcocks look nice but would need other mods done to work properly.
https://mechanics.stackexchange.com/questions/25236/how-does-intake-manifold-runner-length-effect-the-power-curve-of-a-car
my A50RC is a chop and has a Mikuni carb mounted on a reinforced plastic pipe, as its a chop probably for torque rather than top end. possibly also why there is a plunger primer seperate to the carb to help starting.
Hi - the twin carb A65 needs a tufnol spacer between the carbs and the head because the twin carb bikes have no inlet manifold to absorb the engine heat. I went out on my Spitfire last week, for the first time on a very hot night, and the bike spluttered to a halt after about 5 miles. Thinking it was a carb blockage I undid the drain on the carbs and was scalded by the screaming hot petrol that came out, how it didn't set fire I will never know! The hot fuel was obviously vapourising. A pair of tufnel washers seems to have cured the problem.
John.
Thanks for the replies I have found a little bit of info regarding the design of the head it was prone to bad starting when hot as said previously because it had no manifold to get rid of the heat and the fuel would get to hot, so to fit tufnol heat insulators. Thanks again Roy