Questioni have a very hard time starting my bike i cleaned my carb made sure there was a fresh mixture of fuel and changed the plug and when i try to start the bike it will turn over for 1-3 seconds and then shut right off heip me
AnswerHi Chad,
It sounds like your bike is having a fuel problem
but this can result from various things.
If your fuel is new and free of moisture that
is a start. Next comes the fuel flow
to the carb from the tank, check for a
steady supply going to the carb.
Then comes the float and float needle and
valve inside the carb.
If the float is sticky or the needle valve sticks
then fuel could be stopped there.
Make sure those are free and not stuck.
Once the fuel fills the bowl which it should
then the float lifts and shuts the
needle valve off temporarily.
Next is the small passages and jets inside the carb.
These are so small that you may have to soak
the carb in yamaha carb cleaner a few hours.
The jets often need to be cleaned with a smooth
piece of wire like a small guitar string or needle.
They get hardened fuel varnish stuck inside them.
They have to be spotlessly clean.
If you feel your fuel supply is all in good working
condition then also try a new spark plug
and clean the air filter.
If your spark plug is wet the engine may be flooded
with fuel, leave the plug out and let the engine
evaporate awhile.
If you have a compression gauge check the
engine compression. If the compression is low
it will never start. Could be damaged piston or rings.
Some bikes have reed valves near the carb that
can leak or break.
A very close check of all the fuel components
and ignition should help as long as the
engine has reasonable compression.
Make sure there are no air leaks around
the carb area or it will suck in air instead of fuel.
The spark should jump a gap of about 5 or 6 millimeters
and will be a strong blue color if it is good.
Try some carb cleaner spray or starting fluid in the carb mouth,
if you have a fuel problem it should still
run on that a few seconds.
Check your choke system for problems as well.
If the spark is weak it could be a failing ignition
coil or bad plug cap.
Good luck!
Wayne S.
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