Motorcycle Repair: GS850 problem, air fuel mixture, check air filter

Question
Mark,

I have a 1983 GS850 and have just had the carbs professionally rebuilt. When I got the bike back, all was well, the bike ran smooth as silk. Now, about a month later, it has developed a serious problem. After start-up and warm up (10 minutes-approx) the bike refuses to accelerate under a load. It bogs and nearly dies in any gear. No acceleration whatsoever. When I rev it in neutral, it's fine up to about 4,000 rpm's then seems to "cycle". It revs up and down 2,000 rpms on it's own with the throttle in the same position. It's like it's being fuel starved, but I can see fuel flowing fine through the fuel filter. Any idea what's going on?

Thanks for any help,
Duke


Answer
Hi Duke,

The problem could be carburetor or electrical in nature. I would need to check altenator output and other electrical tests.

Bogging is indication of rich air-fuel mixture and/or ignition problems. Check air filter, airbox, and air passageways for obstructions such as nests, wallets, papers, etc... (I've seen them all more than once).

Carburetor synchronization may be off a bit and causing the irratic idle. Intake air leaks cause irratic idle, too.

Describe the appearance of the spark plugs. Are they black and sooty? Black and wet, etc...?

We'll go from there. Use my email to reply: mshively1@woh.rr.com

Visit this website:
www.thegsresources.com


Respectfully,
Mark Shively