33/12 cylinder head

Information relating to Matchless and AJS Models built prior to 1939
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Tazmantic
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Joined: Tue May 25, 2021 10:50 pm
Location: Oxfordshire UK

33/12 cylinder head

Post by Tazmantic »

Hi all yet more questions, Ill keep throwing them out there hoping that the knowledge is here. I have 2 heads that have the same casting/part number but the flange for the carb is straight on one and at an angle on the other, I'm presuming the angled one is correct for the sloper as this will keep the carb level so did they make a 250 big port non sloper?

Also what I take is the non sloper head had the valve springs fitted, when I removed them there is a washer (as can be seen in the photo) at the bottom of the exhaust valve (which appears to be held in by the valve guide) but there isn't one on the inlet valve and looking at the parts list (though I think they either have the numbers wrong) or they put the wrong quantity (as it says there should only be 1 valve spring dish) but the number is for the valve spring cone (which I presume refers to the top washer that holds the collets) so my question in a long winded way is should there be 2 lower washers? as the fins on the inlet side do appear to be designed to hold the outer spring.

Cheers
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Duncan
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Location: HAMPSHIRE UK

Re: 33/12 cylinder head

Post by Duncan »

Tazmantic wrote: Mon Apr 11, 2022 10:41 pm Hi all yet more questions, Ill keep throwing them out there hoping that the knowledge is here. I have 2 heads that have the same casting/part number but the flange for the carb is straight on one and at an angle on the other, I'm presuming the angled one is correct for the sloper as this will keep the carb level so did they make a 250 big port non sloper?
It looks like 1931 models had a vertical cylinder and the sloper fashion came in 1932 : http://archives.jampot.dk/promotional/S ... poster.pdf
Tazmantic
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Posts: 388
Joined: Tue May 25, 2021 10:50 pm
Location: Oxfordshire UK

Re: 33/12 cylinder head

Post by Tazmantic »

Cheers Duncan The ones I've seen with the vertical cylinder don't seem to have a threaded exhaust flange. These short run models are soooo hard to work out.
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