winslow14
New member
Hi, I have a 2000 Yamaha Vmax 500 DLX, It will not start and it backfires about every 3 pulls. I have pulled the spark plugs out and they had a black liquid on them. I cleaned both of them and cleaned them with a wire brush. I put them back in and tried to start it and it did the same thing. I took the plugs out and they were black again. What can i do?
Clean the carbs, replace the plugs, and when the plugs are out pull the motor over to be sure it's not full of fuel(flooded) already.
winslow14
New member
When cleaning the carb is their a special way to apply the carb cleaner, or do you just spray it on?
no1chevyboy
New member
you have to take carbs off the sled and disassemble cleaning the inside jets and passeges along with outside.
winslow14
New member
I heard something about, that you can put your carb in a pot of boiling water to clean it also. Will that work to.
no1chevyboy
New member
i have never done it that way but you would still have to disassemble
winslow14
New member
yeah i disassembled it and sprayed it with carb cleaner.
Remove all jets and the fuel screws, spray carb cleaner thru all holes and then use a blow gun to blow air thru everything also.
Remember where the fuel screws are at for turns out and reset.
Remember where the fuel screws are at for turns out and reset.
Trailman
New member
winslow14 said:
Winslow14, was your sled running and then started backfiring as the motor stopped?
If so it could have holed a piston, hope it's not the case but thought I'd better mention it as trying to start it with a holed piston would flood the motor and can result in a fire.
winslow14
New member
We took it out about 2 weeks ago and drove it around the house. We turned the sled off so we could make a little path, when we tried to start it again it wouldn't start, we thought it might of ran out of gas so we put some gas in. But it still wouldn't start. Ever since then it has been backfiring and not even starting. I cleaned the carbs last night and i am going to try to put them back in today. I hope its not the piston.
mbarryracing
Member
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- Aug 30, 2007
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Sounds awefully like the ignition timing is off if it's backfiring, culprits are usually a sheared flywheel keyway or a faulty CDI box...
The plugs are wet because the fuel is not burning.
First verify you have a good clean blue spark... If all good then next remove the recoil, rotate the crank to put one of the pistons @TDC, check if the trigger notch on the flywheel is near the ignition trigger coil, if it's a ways off then your flywheel / timing has moved and you need to replace the keyway.
Keep us posted with feedback.
The plugs are wet because the fuel is not burning.
First verify you have a good clean blue spark... If all good then next remove the recoil, rotate the crank to put one of the pistons @TDC, check if the trigger notch on the flywheel is near the ignition trigger coil, if it's a ways off then your flywheel / timing has moved and you need to replace the keyway.
Keep us posted with feedback.
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no1chevyboy
New member
i have seen a problem like this and it was bad fuel.
crfbikerboy
New member
if the engine is full of fuel after it was just running....sounds like the needle and seats leaking .
winslow14
New member
k so i cleaned the carbs and put them back on. It started and stayed running for about ten minutes but then it bogged and shut off. When i tried to start it again it made a very loud backfire. What is wrong now.
floats are stuck or fuel needle (port) is bad or it could be your reeds!
winslow14
New member
How do I check the reeds?
stator goes south after it gets warm??? Does it restart after it cools down?
winslow14
New member
It hasn't started other than for 10 minutes. It keeps backfiring very loudly and makes a big blue spark come out of the exhaust.
a friend had this problem and one of the main jets was loose.