Bike cuts-out on landing

Hi All,

I've had my '02 426 for a couple months now and I'm loving it... only problem is on some of the jumps. When I land the bike will cut out for a split second, almost stall, then come right back... it doesn't happen on every jump. What do you guys think?

I'm guessing a float problem because that's the only part I can foresee moving upon impact...


Russ B

You answered your own question - reset the float. :applause:

Also, ensure you are landing with at least a little throttle on. Landing at idle can cause a similar response.....

This may be useless advice, but sometimes I unintentionally tap the brake due to its position. Sounds like more of a float problem, but you might want to see if maybe you are accidentally tapping it. :applause:

I think your foot is landing on the rear brake pedal and makes the engine cut-out. I have done this on my yz450 mostly on one particular jump everytime. Try pulling the clutch in and see if it happens. If so, then I would say you are right to check the float.

Thanks for the responses... I won't be able to get to it until this weekend but I'll let you all know how it turns out.

My 426 did the same thing, and if I hit the face of a jump hard enough it would do it then too which really sucked.

The issue is the float is being driven through the fuel and is flooding the engine on impact. Some guys are puting a stop inside the carb to prevent the float from dropping too far during G forces or impacts. Its a bitch to tune out, but it can be done.

One tuner was drilling and tapping the bottom of the carb and putting a travel limiting screw in the bottom of the carb.

PM Kelstr on this. He may have a measurement for you to simply epoxy a small stantion in the bowl to support the float on big impacts and G-outs.

I was having a similar problem with my 01 426, but it was happening cutting out going up the face of the jump which is even scarier than on landing. The day before I had the carby off and reset the float level so thinking that this was the problem I took off the carby and checked the float level and lowered it a little. Next race, same problem cutting out going up face of jumps and also was missing going up the fast straights. I checked the spark plug and found the lead wasn't sitting on the plug correctly, so thats the problem. Went out in next race same problem. Again checked the bike and this time found the wire to the coil was sitting between the coils of the rear spring, so every time the rear suspension was compressing it was crushing the wire and shorting it out, hence no spark. Cabled tied the wire to frame and problem solved. So sometimes the problem can be something simple.

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