Can't notice any performance difference between the two, or the Bing when it was new, OKO is just a lot cheaper (or was) to buy as a new carb.

Mikunis are a pain as they have the airscrew hidden by the exhaust

I have a Dellorto on my other 340 which works just as well

hi woody thanks for the info. i know what you mean about the airscrew on the mikuni. ive got what looks like a very good bing on my 340 ive just put new slide and needel and needel jet in seems to be abit beter but the bodys also is abit worn so im thinkin to move to a oko or mikuni. the mortor as been rebuilt before i got it im thinking about geting the exhaust repacked do you know anybody who dose it? i dont have cuting gear are a welder. cheers bondy.