I apologise if this has been covered in past posts as Beta carbs appear to a bit of hot topic but I could not see any reference to jetting.

I have just bought an 06 250 and used it for the first time on sunday. It seems to run a bit rich. It is fitted with the statndard Mikuni carb. It starts with no choke and when the engine is warm has to be revved to clean it out before each section or it hesitates when you open the throttle. The hesitation's not that bad buts its enough to cause problems before a climb. It has a 30 pilot jet, 150 main jet fitted which is standard, the needle clip is in middle (3 out of 5) groove, the air screws is 1 1/2 turns out.

Has anyone altered the jetting on theirs to improve this?

Also it's a bit loud and the silencer packing is all but gone. Would you buy a silencer packing sleeve off Beta or use the loose stuff? The reason I ask is I have a pack of the loose stuff already.

Thanks in advance.

Scragg

Give lampkin Beta a ring they sold me a jet kit that solves the richness,145 main 27.5 pilot

i agree with danman10270 the jet kit sorted my 05 bike no problem. at the same time i would also give the top end a strip down and a good de-coke. i also fitted at a later date some dual stage reeds (boysen). these made the biggest difference but i had to go back up one size on the pilot to stop it pre-igniting. overall it transformed the bike. hope this helps. paul.

It's strange, that you say the bike hesitates. Because in a GasGas video the mechanic said, that if the bike hesitates, then it's running too lean and not too rich. Anyway I would say, that it's easier to turn the air screw, and leave the jets as they are. Try what's happening if you turn out a bit (anti-clockwise) the air screw, so you will get a leaner mixture.

Also, it's a good idea to clean the carb, because this can also cause hesitating.

And don't forget, that it is important that how much oil do you add to the petrol. More oil -> leaner mixture, less oil - > richer mixture. Some jets can work good for 50:1 petrol-oil ratio, but they are not working good if you use 80:1 petrol-oil ratio.

I have bought a silencer packing for my 06 and they are good,made for the job, also have put the different jets in. run on 70/1 semi synthatic , seems okay.