1937 AJS 250

Information relating to Matchless and AJS Models built prior to 1939
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1937 AJS 250

Postby NORMAN NIPPY » Sun Apr 28, 2019 11:01 am

could you tell me how to work the manual advance system, do you adjust for road conditions

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Re: 1937 AJS 250

Postby Rob Harknett » Sun Apr 28, 2019 12:09 pm

No, not to road conditions. You could damage the engine, by overheating it. Before you do anything else with the bike I suggest you read your driving and Instruction book. http://archives.jampot.dk/book/Owners_m ... n_Book.pdf
Which you have not done, to ask that question. Almost the very first thing it mentions is, the AR lever. It states, on starting set it in the midway position. This does vary from bike to bike. This being due to ignition timing and points gap, which could slightly vary when setting up. If in the midway position the bike proves difficult to start, by spitting back. ITs too far advanced for starting. So retard it more, so it does not spit / kick back. Allow the bike to warm up a little. On moving off, gradually advance the lever. Doing this before its warmed up may result in the engine cutting out when you shut down the throttle. You'll get used to knowing when the bike is warmed up. Once warmed up the engine should be run with the lever fully advanced. If you are wondering which way the lever goes to advance and retard. Start the engine with the lever mid way or more retarded. When the engine is warmed up, move the lever, if revs speed up, you are advancing the lever, revs will slow down if you retard the lever. If you run the bike retarded when warm, it will probably only do about half the speed its capable of. You will also over heat the engine, which could cause it to seize and cause damage to piston and bore.

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Re: 1937 AJS 250

Postby Duncan » Sun Apr 28, 2019 3:21 pm

I find my 37 250 a lot more sensitive/apprecieative to having a small degree or retard on long hills when the reves are dropping right off than say a 350 would be, I don't have any hard and fast rules other than going by feel, I only normally retard it briefly to give the engine some time to work up momentum before setting it to full advance again, my best advice would be to go and have a play with it and see how it feels as no two bikes respond the same.

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Re: 1937 AJS 250

Postby Rob Harknett » Sun Apr 28, 2019 6:03 pm

True Duncan with the 250, also I am usually 2 up. However, I use the gear box, allowing the bike to pull us up hill at the speed is happy with, with the engine not labouring. The little 250 does not pull uphill well. So I would say when it feels the engine is under strain, drop a gear. This is what the instruction book tells you to under Driving " Do's & Don'ts " This page is missing in the 1937 Driving and Instruction book. Note the section suddenly ends untill.... You can read in the 37 Matchless book, where the driving instruction's continues on from until. ( I'll have to correct that 1937 book, never noticed that page missing )You could refer to driving instructions in the Matchless book here. http://archives.jampot.dk/book/Owners_m ... 20Book.pdf
You would of cause still have the engine a little retarded, if you come upon that hill before the engine is fully warmed up, which I think Duncan was referring to.
A complete version of the 1937 AJS singles instruction book can now be found here. http://archives.jampot.dk/book/Owners_m ... mplete.pdf

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