Motorcycle Repair: 1985 Honda Shadow 500, vacuum petcock, vacuum source

Question
when i ride and get into 6th the bike looses power then dies. took it to a shop and he disconnected the vacuum lines. now the bike has no power in 6th

Answer
Jeremy, not a lot of info to work with here...

WHAT vacuum lines were disconnected? How many miles on the engine? How long have you owned it? How long has this been a problem? Are both cylinders firing all the time?

http://www.bikebandit.com/houseofmotorcycles/honda-motorcycle-vt500c-1985/o/m171...

There is a vacuum petcock diaphragm on the fuel tank which must be connected to a vacuum source on the carburetors. If the diaphragm fails inside, you get a vacuum leak and reduced fuel flow to the carburetors.

Check the gas cap to see if it is venting properly. If it can't draw air into the fuel tank, as the fuel level goes down, it will cause a vacuum in the tank reducing fuel flow. You might want to check the fuel screen inside the fuel tank on the end of the petcock fitting to see if it is restricted.

Bill Silver