AJS wont start.

[brian68]

Hi,
I have an AJS 250 single 1961 vintage.
Which just cut out while running.
Have renewed point's, coil, condenser, spark plug, jets in carb, needle.
Carbs clean. checked timing over and over. still wont start, just spits back through carb.
any help to why this is happening. would be greatly thankful.

Regards
Brian.

[BEAMA]

POSSIBLY VALVE SPRING, TAPPET, ROCKER , PUSHROD / CAM PROBLEM ?

[Blue]

Is it a two-stroke? if so the exhaust might be clogged - but i wouldnt have thought it would cut out from that.  still worth a look (and a clean out does em good anyway)

also i assume you've checked that the plug is actually sparking as you kick the engine over?

[Searchguru]

Hi Brian,
I am probably going to state the obvious which you may have already done. So I apologise in advance.
Is the battery fully charged following your abortive attempts to start it?
Is there a spark at the points as they part?
Is there a good spark at the correctly gapped plug?
Check the plug cap connection to the HT lead as it may be failing when the plug is screwed in and in that position. Check the low tension wiring to the coil as it may have worked loose or only making a connection occassionally.
Is petrol getting into the cylinder?
Is it good quality petrol and not what's been in the tank for a while?
Was/is there any crap or water in the float bowl?
Is your carb float actually floating?
Tappets correctly adjusted?
Any air leaks in the inlet or exhaust manifolds?
Good compression?
Check the timing for a third or fourth time.
If you've got fuel mixture getting into the cylinder and you've got a decent spark at the right time then I am at a loss.
If these points don't sort it out try bump starting it down the steepest hill you can comforatbly push it back up, if needed!  
Alternatively if you can get someone to tow you with another bike up to bumping speed and you might get the beast started, in the highest gear possible. This can be hazardous and is not for the faint hearted (either of you).
I've had stubborn bikes that once started on a bump have been fine forever more. You may have already solved your original problem but it's just being contrary and making you chase your tail.

PS. Don't tow it with a car because that's illegal and we wouldn't want that, would we?
PPS. If it still won't start, I'll give you a tenner for it! Take it or leave it.

[brian68]

hi guess what iwas trying to time it on the wrong t.d.c i.e without both valves being closed have now sorted it many thanks for info
regards brian