QuestionI just got a 1986 suzuki 125dr dirt bike and when i open the throttle all tha way it sounds like its not gettn tha gas and wants to cut off. I have cleaned the carburator 3 times and its still doing the same thing. What else could i try to fix the problem?
AnswerHi Jason,
The high speed fuel mixture is controlled mostly
by the main jet in the carb. That is the one
directly in the center when you remove the float
bowl.
A lack of fuel can occur if the main jet is plugged
or the carb is not getting a good supply of
fuel from the gas tank.
Also the float level can be adjusted on
some carbs. The fuel in the bowl
should be near the top when the level
is correct. If the fuel level is low in the
bowl it will not provide enough fuel.
Check your spark plug to see if the bike
is getting too much or too little fuel.
Reading the spark plug after a fast run with
a clean plug can tell you about the engine
combustion.
http://verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm
If the plug is black or sooty it means you
are getting too much fuel.
This might be a dirty air filter or
a plugged exhaust pipe.
Too little fuel can also come from an air leak
around the carb or the intake tube.
If the bike sucks too much air in it leans out the fuel
mixture. Make sure the carb is on tight and
the intake is not leaking air anyplace between the
carb and engine.
So, you need good compression, enough fuel, right amount
of air and a good spark to make it run.
Check the spark plug condition by that chart above and go from there.
Good luck!
Wayne S
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