mikuni tmr40-38 info needed...

Anyone have any info on this carb. I have one on the 2001 KTM 640E I just bought and it ran fine for a week and now won't start. It still has spark and compression, but seems to not be getting fuel. Any help would be appreciated.



Hi Pete,

Most LC 4s come stock with a BST 40 Carb....

On the LC 4 the fuel line into the carb may become kinked if not routed properly and shut off supply.... Crack your float bowl drain screw to make sure fuel is getting into the carb... Check that the fuel cap vent is working....

Once you establish fuel flow is good into the float bowl you can go further and pull the spark plug to see if its wet from fuel... If no fuel is getting into the combustion chamber you may need to clean the passageways and jets in the carb, check the float height and confirm your valve clearances are good.....

Good luck..



You're on this board too huh? It is definately not a BST. I looked at the carb and it is stamped as a FMR-40-38. It has no round black top like the BST....flat and aluminum. I think the first owner put in the slide carb when he put on the full akro exhaust.

I will check the float bowl to make sure fuel is at least getting to the carb.

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