Motorcycle Repair: my suzuki, vacuum petcock, plug caps

Question
i have a 1985 suzuki 750 and when i go into 3rd gear it kind of bogs out could that be the plugs or plug wires bad?

Answer
Jeff... ONLY in third gear? Plugs/wires are load related, but you would notice the problem in all gears under load. Spark plug caps should have about 5k ohms resistance. Look at the plugs to see what they are telling you about the engine's running condition. .....  Black, oily, brown, white.... lots of possibilities.... too rich, too much oil past the rings/valves/stem seals, too lean due to fuel contamination or manifold air leaks. Any changes to the exhaust or intake systems usually require rejetting.

I don't know if you have a GS750, GSXR750 or Katana, so I can't really guide you into those areas with any detail. Check the www.gsresources.com site for model specific info.

If the bike has a vacuum petcock, the diaphragm may be getting weak, slowing down the fuel flow. A dirty fuel filter can do the same.

Bill Silver