Motor problem, cuts out at speed.

UPDATE: 5/31/09 Thank you, all of you for your assistance. I did check the float level and found it was off, I adjusted it and that fixed the hesitation problem, but the motor still cut out at high speed. I continued to check to see if it was electrical or fuel, so I hooked up a timing light and ran the motor, surprise! I found that it was electrical and at high revs the timing light went out. So there is a short somewhere in the distributor. I replaced the coil, so I opened the distributor and checked the leads on the coil. I found that the positive side of the coil was slightly twisted and was grounding out (jumping over) against the to the center of the coil onto the spring inside the distributor cap. The insulation was burnt and worn. I replaced the insulation and added an extra piece of shrink wrap to the terminal leads and re-routed them clear of the center. It worked. The motor runs great now. I completed a test drive yesterday and was very happy with the result. Thank you all again for all your help! Ron
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I am having a problem with my M151A1. It started after I drove it about 17 mile to a local parade last Saturday, I was traveling about 35 miles an hour when the engine died. No back fire, no surge, just died. I tried to start it and it did sputter for a while but failed to fire. I could smell gas, so I took off the air duck pipe. After a while it still didn't start. When I got it home, I replaced the coil, condenser, rebuilt the carb, replace the plug wires, installed new plugs, checks the timing, swapped out the electronic ignition module, still it didn't correct the problem. Now it starts and runs well at idle but when you step on the gas it hesitates, like it is flooding out, When you have the throttle open at about 1500 rpm, it runs OK but then seems to die out. I can still smell gas in the exhaust. Got any ideas? Thanks!

I plan to check the float level and fuel pressure. Thanks for the help!

When you rebuilt the carb did you check the float level? Did you dip it? My next guess would be to check the fuel pressure or make sure the needle and seat is good and working properly. What did the plugs look like? Does it look like it is getting too much or not enough fuel? Make sure the transfer ports are clear. I just fixed a friend's 750 Honda motorcycle. It had some dirt in the off idle circuit. It would idle or go wide open, but if you cracked the throttle slowly it would die.

Is your A1 stock or modified? What I'm asking is does it have the stock in the tank electric fuel pump or has it been modified to the A2 mechanical fuel pump? If the electric fuel pump then check to make sure it's pumping enough fuel and a steady stream. I had one that would pump in spurts and only little amounts. If the A2 mechanical make sure that the diaphram hasn't gone bad and that anytime you excellerate it stops pumping fuel.

You said that you checked the plugs and wires etc. Have you checked to make sure your getting a good strong spark?

Those are the only things I can come up with.

Reasons might be many: Fuel pressure, float level, fuel filer. This is for you changed allredy the electrical side. However, is the timing correct. Is the old (even NOS) condensor working propperly. Did you check the condensor for a short? Any 4.7 mikofahrad condensor will be fine as a replacement.
Wolf from Germany

Sounds like an electrical gremlin. Check all the battery connections, the grounds to the chassis and the coil power wire.

My experience with the mutts has shown the small fuel filter that screws into yhe carb is easily plugged,requiring another ,larger filter prior to that filter.When you remove the small filter and blow through it, if you have any resistance ,replace it. I eliminated many problems by doing this

Problem solved.

Thank you for the replies. I fixed the hesitation problem by adjusting the float, then things ran great for a while then it died. Turned out the electronic ignition module went out. After that was replaced, it runs better then ever.

Thank you all for all your help.