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czrider

Port Timing For Villiers 32A

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Hi there,l was wondering if anyone could help me with the optimum port timing in degrees for the Villiers 32a motor for trials, both opening and closing of ports.I am looking also at exhaust header length, is there a formula that may apply? I notice quite long headers in various vids.

Thanks.

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think the longer headers give you better low end power and torque....just what the trials doctor ordered

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I must admit that I have never seen any actual figures for Villiers engines, and the Villiers guys who are selling new 'Challenger' engines don't know what state of tune they are using.   The only thing I remember being told was to remove 1/8 inch off the top of the exhaust port, and about the same from the inlet side skirt of the piston, to make a Racing type engine.  ( Also to leave the transfer ports alone.)

You mention 'opening and closing' timings... they are the same for two strokes..!

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You don’t say if you are using the cast iron cylinder or one of aluminium alternatives. Lengthening the inlet manifold by (as much as space allows) I used to fit an inlet manifold extension 2inches long which produced more low down torque or plonk. This tends to reduce the engines high rev performance. Fitting more than one cylinder base gasket has the effect of altering all the port and transfer port timing and can be a useful way to experiment without machining the ports. Compression ratio is reduced by a tiny amount, but skimming the cylinder barrel top restores it.  I used to cut a window in the piston to allow the inlet longer exposure, this requires careful measuring and careful checking with the inlet manifold off to allow the piston skirt at tdc to be marked. You do all of this at your own risk. However most Villiers engine officionardos will probably say to leave well alone and concentrate on getting the carburation and exhaust spot on. Crankcase stuffers can improve the crankcase compression, as can ensuring the main bearings and seals are in perfect condition. I would add that most people using the Villiers engine just use them as the factory built them, including the then of the time works riders. Most preferred the bob weight original crankshaft, in my last Villiers 32A I fitted a full circle Alpha-Stepha polished crank assembly with knife edged connecting rod. That all sounds good but in reality there isn’t much difference between the two. 

Good fuel, the correct oil and mix ratio, clean carburation, optimum ignition setting and making sure the drive side main bearing receives adequate cooling ( the crankcase design shrouded the housing too much) and a good 32A motor should see you happy.

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