Hi

I have a 2013 Beta Evo 4T which has started running very rich.

It is fine on tick over but give it some revs and you get a cloud of black smoke.  It also uses a lot more fuel than it did.

It is not the choke stuck on.  I can see the choke effect when I start it.

I have cleaned out the carb and lowered the needle one notch but with no effect.

Beta UK tells me they cannot supply any carb spares.

Before I take the carb off again, any ideas on the possible cause of the problem?

Thanks

Stuart

@stu109 https://www.trialscentral.com/forums/topic/66257-evo-300-4t-fuel-issue/page/2/  Take note of the point about failure leading to carb flooding. I am not saying that this is your problem just that it may be worth checking the solenoid function to eliminate it from the investigation.

My Beta once ran the same exact way.  It would idle nicely and doing tight turns was fine but if you tried to rev it up, it sputtered rich.  I had left a rag in the air filter after washing the bike.  You could inspect the air box. 

https://www.frankmxparts.com/rebuild-repair-kit-MK-BSR33-79-Mikuni-BSR-33-carburetor-2008-2022-Beta-EVO-300-4T-Trial

IIRC, that model carb is also used on a 400cc quad.  If you search the model number of the carb you should find what else it fits.   

Edited March 12, 20251 yr by mcman56
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