Motorcycle Repair: bike hesitates,bucks,holds back power when driving, combustion chambers, open pipes

Question
2006 hellbound steel hellion model,,,s&s g carb,, trying to get the adjustment just right,,but its not happning,,im ready to throw in the towel,,,help,,,,,,lol

Answer
Hi Joelle,

Throttle transition problems are common on
the S&S G carb.

You can sometimes move the problem so the
transition from low speed to high speeds
is not so evident by using a larger
air bleed jet.

First make sure you have a good
float needle/seat and that the
float level is okay.
Too high or leaky float will
cause flooding.

When tuning any carb always use your throttle
position as the key to finding the problem.
If the problem is at idle then address the
idle jet and circuits. If the problem seems
mid-throttle then adjust the intermediate
jet, three quarters to full throttle problems
are the main jet's area.

Intake air and exhaust system are also
considerations.
Most bikes run bad with open pipes,
the back-pressure of stock or baffled
pipes can assist your power output
by keeping the fuel charge inside the engine
instead of in the pipes.

Another key to tuning is the spark plug
color. This is a sure way to see what
is happening in your combustion chambers.
If your plugs are wet the bike is flooding,
choking or misfiring.
If the plugs are oily then valve seals or
oil control rings are weak.
If the plugs are sooty black then you have
excessive fuel or a lack of air intake flow.

http://verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm

A bike that coughs or bucks may be running too
lean at some point in the carb settings.
It could also just be air leaking around
your intake manifolds or carb mounts.
Air leaks can lean out the fuel mixture.
You can use propane or carb cleaner
to check around the intake for leaks.
If the engine speed changes then you
know it is sucking the propane or carb spray in
through an air leak.

You can't adjust the carb unless the intake
and carb seals are leak proof.

Here is a basic guide from S&S that
shows the jets:
http://www.google.ca/url?sa=t&source=web&cd=1&ved=0CBcQFjAA&url=http%3A%2F%2Fwww...


My suggestion for jets would be 33 intermediate,
84 Main and 48-50 (3/64") air bleed.

Check for air leaks, check choke, check float level etc
before changing the jets though.
A bad accelerator pump will cause bad bucking too.

Good luck!
Wayne S.
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