Engine Specifications G80 Short Stroke

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Engine Specifications G80 Short Stroke

Postby Ian Saker » Mon Nov 11, 2019 5:15 pm

Hi, hope some of you knowledgable people can heip as i am assembling (at long last) my 500cc shortstroke motor 1966
and would like to get things correct. The info on these engines is a bit sparse after trawling the archives.

Ignition ttming is 38 degrees fully advanced ?

Inlet and Exhaust valve timing and what tappet clearance to use when checking?

Tappet clearance to use for normal running and should it be set hot or cold?

Many thanks
Ian

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Re: Engine Specifications G80 Short Stroke

Postby ajscomboman » Mon Nov 11, 2019 5:57 pm

Yep 38 degree full advance or 10.98mm

Tappet clearance nil inlet and .005 exhaust set cold.

inlet opens 18 before TDC and closes 69 after BDC exhaust opens 50 before BDC and closes 30 after TDC .016 valve clearance when setting.

Cam mark 1 for exhaust and number 2 for inlet

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Re: Engine Specifications G80 Short Stroke

Postby robcurrie » Mon Nov 11, 2019 7:26 pm

ajscomboman wrote:inlet opens 18 before BDC

Shouldn't that be TDC ?

Rob C

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Re: Engine Specifications G80 Short Stroke

Postby ajscomboman » Mon Nov 11, 2019 7:29 pm

robcurrie wrote:
ajscomboman wrote:inlet opens 18 before BDC

Shouldn't that be TDC ?

Rob C



I'm dyslexic yep you're right! :rofl: I'll go back and edit it.

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