Motorcycle Repair: runs bad at times, long term storage, yamaha 1100

Question
My yamaha 1100 v star custom looses 10 20 percent
of its power at any time durning a days ride.
After stoping if I gun the engine it will backfire
via carbs or die- after restarting the ride will be strong or at 90% power to latter run 100 %.
I have drained the fuel tank & carb bowls this seemed to help then latter run poor all over again.
have any answers
tx Dan  

Answer
Hi Dan.
 Does the bike sits in seasonal or other long-term storage?

 If so, then you could have a problem with your carbs being in need of cleaning, in which case, the tank has contaminants in it as well.

 If you are getting fuel from the same station on a consistant basis, try changing to a different station for a while and see if that has any effect.  You could be getting substandard quality fuel.  We just had a big todo about it here in South Florida, so it is a very real problem.

 Check the connections of the carbs to the intake manifolds as well as the manifolds to the heads.

 Check the electrical connections and wiring in the ignition system (bad connections/shorts) as well as the spark plug may not be properly tightened down.

 There is a very real possibility that you could have a few minor things wrong that, on their own are not noticable, but combined will cause problems.  There is also the possibility, which is most likely, that you have one problem from bad fuel, something shortng or coming loose.

Let me know what you find.
Good luck.
FALCON