losing power!

[caz.k]

Hi, i have a 1986 honda shadow vt700 that is having trouble reaching high speeds. when i reach 55mph, the back cylinder just shuts down and eventually the bike does also. at first i thought it was a fuel problem so i cleaned the carbs. then i was told it was an electrical problem, so i changed all plugs and replaced the stator, and rectifier. i also swapped the coils and it was still the back cylinder that shut off. i am stumped.

[gat803]

When the engine (or even one cylinder) dies, have you tried opening the carb bowl drain/drains to see if there is any gas in the bowl?

[finjoey]

When that cylinder starts to drop out...try putting the choke on to see if
it keeps it running...sounds like a fuel issue...This only happens at higher speeds...Right...lower speeds will it run fine...right ? Good Luck

[caz.k]

no i have not touched the carbs since i originally cleaned them...what would the carb bowl after it dies tell me? and not exactly, it does run at low speeds, but the power is low.

[luisr320]

Originally Posted by caz.k

no i have not touched the carbs since i originally cleaned them...what would the carb bowl after it dies tell me? and not exactly, it does run at low speeds, but the power is low.

If you open the drain bolt from the bowl immediately after it stops, you can see if the problem is a fuel shortage, because at that time, there will be almost no fuel in the bowl.

Other reasons may be: air filter, or fuel filter. Try running the bike without the air filter on. If that solves the problem, replace the air filter. The fuel filter is cheap, so just replace it anyway.