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Motorcycle Repair/Yamaha big bear 400

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Question
What cause it to start back firing and stalling out when it gets up to a certain speed.

Answer
Jason,this is a tricky one. It could be a number of problems. The CDI cold be going out or the pick up coil and stator could be going out. It could be the coil or even the resistor plug cap on the coil wire to the plug. Some of the big bears would even bend the crankshaft key that holds the flywheel in time. Some testing is in order to narrow down the problem. Inspect the spark plug to see if its charred or lightly brown. There could even be a valve clearance problem that they are to tight and don't have enough clearance when they heat up and float out also making it hard to start. Some testing is in order before you spend any money on random repairs. If you can get your hands on a Clymer manual it will help you in testing and narrow down the symptoms.

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Gary Blake

Expertise

I have built from ground up race winning motocross bikes and atvs as well as atv,s for flat track and TT racing. I am starting to take on the utv challenges now for racing. This is a new area for me so Im in a learning curve.

Experience

I have extensive experience in off road motorcycles and atv,s.I also work on street bikes and personal watercraft, Some experience was self taught and some was factory trained. I have been working in the powersports industry since the mid 70,s I hope I can help. Thanks Gary

Organizations
Was a sponsor for K.O.R.R.(kansas off road riders) and now I am working with ROMEO,s (retired old motorcyclists eating out)and was in charge of the Quad Wars for the monster truck series in Central Kansas

Education/Credentials
Factory trained Kawasaki Heavy Industries. Factory trained GasGas motorcycles and atvs worked as a technician and was as a dealership owner.Kaw.Suz,Honda,Aprilia,Arctic cat,See Doo,Can Am, Bombardier,Yamaha,GasGas,Qingi,TM,Moto Guzzi,Harley,s

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