37/22 valve cap

Information relating to Matchless and AJS Models built prior to 1939
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37/22 valve cap

Postby ajsimpson » Sun Nov 24, 2019 10:39 am

Hi all

I am rebuilding my 1937 model 22 engine and on stripping it down have noticed a hardened steel cap on top of the inlet valve stem, does anyone know if there should be one on top of the exhaust valve too? Seems odd to have just the one.

Hoping someone can shed some light.

Cheers

Andrew

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Re: 37/22 valve cap

Postby Rob Harknett » Sun Nov 24, 2019 11:27 am

Both original valves should have the end cap. However, the valves are not easy to find. There were quite recently plenty of inlet valves available. In fact not long ago I picked up a carrier bag full. I soon got rid of a few and the club took the rest. I think they are now gone. The exhaust valves are the ones that get burnt and need replacing more often. I guess the reason why NOS inlets seemed plentiful, but exhorts non existent. I believe in the WD/post war era there was a slightly longer stem valved that would act as a replacement. Checking the length of your two valve stems may show your ex. valve has a longer stem. Which would equal your inlet valve stem length with the cap fitted on the inlet valve. If you need a stem cap the club should have them in stock. Do not ask for part no. STD 685, you will get a reply sorry no. Since 1952 AMC introduced new part numbers. So any parts prior to 1952 that continued in use, got a new part number. So ask for pt. no. 000685 valve stem cap. Bear in mind when searching old stock it may be found as STD 685 or 000685. When searching for valves do the same. Your 37 parts list will give a 3 digit number prefixed STD. just delete the STD and prefix the number with 3 zero's. Old stock at jumbles etc. may be found still using the old pt. no.

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Re: 37/22 valve cap

Postby ajsimpson » Sun Nov 24, 2019 12:00 pm

Hi Rob

Thanks for the info. The valves are still serviceable for now, but i will certainly keep an eye out at jumbles from now on.

Cheers

Andrew

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Re: 37/22 valve cap

Postby Rob Harknett » Sun Nov 24, 2019 1:18 pm

The old bikes are not that fussy Andrew. I have a 36/22 found in a field. I have not even had the head off it and so had since 1986 done a few 1,000 leaky smokey rattley miles on the old thing. All its ever asked for is a clean plug and points after a winter lay up and lots of oil.

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