Motorcycle Repair: 1980 suzuki gs850, plug caps, valve adjustments

Question
I have a 1980 suzuki gs850 that bogs down when put into 5th gear. It idles fine, and runs great for any speed thru 4th gear but when I put it into 5th gear it stalls out. I have taken the fuel system, carbs, and air system out and cleaned them...any other ideas? thanks....

Answer
Adam, this isn't my brand, so I can only give broad guidelines.

Try  http://www.thegsresources.com/ for model specific info.

Sounds like the bike is running out of fuel at high speeds in 5th gear.
Fuel petcock filter restrictions, fuel cap vent blockages are the most common issues with bikes in general.

I would verify compression readings, valve adjustments, spark timing at idle and full advance.

Beyond that, if you have changed the intake or exhaust systems, you may need to re-jet the carbs for more fuel flow at high speeds.

More subtle issues can arise from low voltage to the ignition system, bad spark plug caps, fouled spark plugs or weak coils.

Bill Silver