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Bogging, bogging, and more bogging

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I've recently restored a 1972 Husqvarna 250wr, and only rebuilt the top-end. My problem is that I can't get rid of the lower-end bogging from closed to one-quarter throttle. I have a new 36mm Mikuni on the bike, and have progressively changes the pilot jets from the stock # 40 all the down to a #25, then all the way back up to a #50, but the motor continued to bog no matter what size pilot I install ? The plug, gasoline, air filter are all new and clean. Can anyone give me some advise on what to do, or try next? Thank you in advance.

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What needle and clip position?

Needle plays a huge roll down there.

New Mikuni's are fussy. I can only imagine trying to tune a 72'.

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What main jet is in it? It sounds like the pilot circuit is still to lean. If going richer on the pilot doesn't work, raise the needle up a couple of slots and try again. I know it's a dumb question, but is the carb installed in the correct orientation? The choke lever should be on the left hand side.

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First of all, I think a 36mm is a bit big for that bike. I think it came with a 34mm or 32mm. In 1972 a hot 175cc used a 30mm. That bike is a piston port and no reed valve. I would check and see what jetting on a Mikuni was on a 1972 250cc Suzuki . That was a piston port engine also. Or 1971 Yamaha.

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I run a 32mm on my 1973 Cr125 and it's fine. 36 should be fine for a 250.

Is it a new carb? If not, is the slide worn? Check that the choke (enrichener circuit) is fully closed and sealing. Is the float level OK? Is the float valve shutting off — check the little rubber tip on the float needle for any grooves. Is the pilot circuit clean? If all those different pilot jets didn't make a difference, look in there.

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