AJS & Matchless Owners Club

I have been trying to improve the reliability of my recently acquired AJS 250 CSR. Initially it would run for about a few miles and then stop. I believe it was due to the float valve in the carb sticking as it would restart once fuel was bled through the system and run for another few miles then conk out again.

Now however, it starts but then stops after a few seconds and will only run by depressing the tickler on the carb - lots of revs!! - not ideal. I have blown compressed air through all of the jets, etc. but so far to no avail. The only improvement is that it starts slightly easier.

It has always been difficult to start and spits and pops through the carb on occasions when being kicked over. It will also kickback and break your leg if you aren't careful.

Any ideas??

"Recently acquired", You really need to start from scratch and check:- Timing, sounds too advanced and possibly not fixed firmly.Check coil and condensor.
Carburation, blowing air through the jets doesn't necessarily mean its clear, you need to check physically, especially the slow running/idle jet and corresponding air-way in the carb body. Clean the banjo/filter where it connects to the carb.
Check spark plug and h/t lead. Check how the bike performs after each procedure, that way you will know what was causing the probs. Good luck and let us know how you get on.

I think your coil is defective or/and your ignition timing is out. After some considerable time playing about with it, my 250 Matchless only spits back through the carb when I've been trying to start it after a long lay off and when it's being reluctant to start so too much fuel builds up in the cylinder before it goes bang. Normally it doesn't kick back, so much so that I am happy to start it wearing sandals.

Check the fuel tap filters and tank itself for rust or lining being eaten by the dreaded ethanol!

Certainly appears to be too far advanced when starting. I have 3 lightweights but dont have them to bits often, BUT, if they have auto advance & retard like the heavywieght mag has, this could be stuck in the fully advanced possition.

If the tap filters in the tank are blocked, I suggest you remove them and fit an additional filter in the fuel line instead. 'In tank' filters were fine when the bikes were new but old tanks will produce rusty flakes etc. for ever, causing continual filter clogging and regular removal of said taps.

Check the springs on the bob weights, if these are weak it will be advanced at tick over speed.