Hi, wonder if you can help.

I have just got a new to me tl125 running, fitted new original carb, coil, plug etc and set it all up. However after riding for 10-15 mins when I drop the revs to idle it won't pick again. Opening thottle just causes a stuttering farty idle. if I ride it along on idle, after a few mins it will eventually pick up.

Check for carb air leak and blocked tank vent, but nothing evedent. I have a bakealite original looking carb heat shield fitted too, so not sure if it could be heat on carb bowl. Any ideas? Thanks

Does it seem to run ok when cold, and then slowly gets worse as it warms up? Does the choke make any difference?

Hi,

Yes she runs fine when cold (has some off idle hesitation, but assume this is the standard 'cough').

I have not noticed it as gratual, engine runs fine then when I reach a stop (after 10 mins or so riding) and let here idle she would rev.

I have played with the choke during this fault and putting the choke on stalls the engine. If I pull the choke on and then off quickly I can sometimes get the engine to rev again as normal, but more thimes than not it does not have an effect.

When I do get it to 'clear' it seems to run okay as long as I don't drop back to idle.

Thanks for your help!

Sounds to me like it is time for a thorough cleaning of the carb. Check all the little passages and jets, also and inlet or in-line fuel filters.

When checking the carburettor see if the float height is correct to the specification. There can be some different figures quoted but a careful check should find the right value for your carb.

Another check worth doing would be look at the contact breaker points with the engine running. If there are a profusion of sparks the condenser might be on its way out.

Hope this is of help.

Thanks all, will check as you advise and report back....

Hi

check that the choke is closing fully, take it apart and check i have have had the same problem

cheers

Hi All,

Just a quick update. Stripped carb, set up float, checked choke and fuel filter. Nothing seemed obvious.

Checked points and there was some sparking, but normal I think. Then I thought I'd check the timing while I had the cover off. Then I found by adjusting the timing I could switch the fault on and off! So I have adjusted timing to get rid of it then rode for a good long while and it seems sorted!

Thanks for your help!

Mat

Glad to hear you have this problem solved! I have a pair of TL125's I'm bringing back to life. One is a 73 very tired barn find, the other a well kept 75. Now that you have the bike running well it's time to work on the suspension. Rear shocks are a must purchase to be competitive. And if that's the direction you're headed, consider the engine mods available. I chose the CB550 piston upgrade for the 73 and will later install the 150 big bore kit on the 75. Big difference in power! A set of modern trials handlebars help, too.

Good luck!