Vintage Dirt Bike Q & A

My elsie has what looks like a 34mm older Mikuni carb. The bike starts right up but never seems to clear out. When i turn the gas off, it then starts running great and really hauls butt!! I'm thinking that it is flooding itself out when the gas is on ...What do you guys think. Also , I have tried to locate a float needle and seat with no luck. Any ideas on parts for these older mikunis? Thanks in advance. Jon

Sounds like your needle is sticking, or there is junk in there. If its been sitting, run down to the auto parts and buy a gallon can of "Carb Cleaner", the kind that has the basket inside. Pull the carb apart and let it soak (no rubber parts though). Then blow it out good with spray carb cleaner, then blow it out with just air. The goop that sits up inside the carb can only be removed with the "soak" type of cleaner, the spray can won't break it up. Then when it's clean, install a rebuild kit..

Here are a couple of places..

http://www.sudco.com/ http://www.carbparts.com/

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Frankie
75 Honda 250 Elsinore
Findlay, Ohio

While you have it apart cleaning it, I suggest you measure your float level, it could be too high. I can't remember the spec but you should be able to find it in the factory or a Clymer manual. I recently completed a project Yamaha and the float level was way too high. It gave similar symptoms that you are describing. Once I got the float level right I was able to jet it correctly. After you confirm the float is the right level take a look at your pilot jet and main jet #.

Thank you for your tips! I ordered a needle and seat from carb parts. It screwed right in and the bike once again runs like a raped ape. Thanks again! Jon