Mikuni VM Carb

Discussion in 'Tech Talk' started by Pete649, Jul 13, 2019.

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  1. Jul 13, 2019 #1

    Pete649

    Pete649

    Pete649

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    Hey Guys,

    I’ve got a Honda CRF70 that I’ve built with a TBolt 108cc stage 3 stroker kit (part no. TBW0968) and the kit comes with a Mikuni VM 26mm carb. Since I’ve built the bike (back in 2015) the carb has always flooded out the overflow even when it was brand new, I’ve mucked around with it a bunch of times and I’m just over it. It leaks fuel even though the float height is perfect or even if I lower it.
    Anyway my main question is has anyone run a 28mm Mikuni flatslide with this engine setup? I’d rather swap to a flatslide if I can because it’s a much better carb anyway but I don’t want to go too big for the motor. If not I can keep trying to get the 26mm to stop flooding or just replace it with the same carb if I have no luck.

    Cheers, Pete
     
  2. Jul 13, 2019 #2

    XXX-747

    XXX-747

    XXX-747

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    Hey Pete yeah funny I’ve had similar issues with a vm26 as well
    before giving up on it give it another tear down and check to see the float is moving up and down properly and isn’t getting stuck
    take the jets out and really good clean use some carbie cleaner with the little plastic straw thing like what comes on a wd40 can I use it to blow out and clean my jets and also look to see that your pilot jet isn’t to big as that could be why it’s letting in to much fuel but otherwise just buy a replacement from tbolt if all else fails lol
    26mm is a perfect size for your motor specially if your bike is for road use it’s the best of both worlds good down low and good for cruising in top gear I’ve run from 20mm to 28mm on a 110 and found the bigger it was the more I had to play with both jet sizes or sprocket sizes
    But with standard jet sizes and sprockets basically the bigger the carb the better the top end the less punch you’ll have down low and the opposite for the smaller carb but you want a happy medium that’s we’re changing jet sizes comes in and your front and rear sprockets hope this helps
     
    Last edited: Jul 13, 2019

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