Motorcycle Repair: Stumble / surging @cruise, jet needles, suzuki gs750e

Question
Hi Mark,
I have a 1983 Suzuki GS750e, Yoshimura pipe, very stock other than that. I've had this problem on and off for the better part of a year. Sometimes it's worse than others. Lately it's too bad to ride. If it's a lean cond. I don't want to burn it up. Full throttle snaps are good, acceleration is good,idle is good, wide open pulls are fantastic. Cruise, it stumbles and feels like a cyl. drops in and out. The plugs all read good(light coffee color). No variation plug to plug. When the engine is hot, it's worse. All the fuel bowls seem to have the same cc's of volume. The petcock is functioning properly by all indications. Both coils crack a mean spark, hot or cold. I hope I've included all the nessesary info for you to make a educated judgement call. Any insight would be appreciated. I realize you must be a busy man. Thank you. email is AnytimeAutomotiv@aol.com

Answer
Hi Mike,

Very good description, thanks.

The problem is in the carburetor's low (pilot) to mid-range (needle set) areas.


I suspect the following:

1) needle jets (seats) are worn, jet needles not tuned correctly, or both.

2) water or other contamination in fuel.



Ensure the air filter is clean and in good condition.

I'll send carb tech filoes to your email. Keep me advised on your progress. Email me directly.

Visit "www.thgsresources.com" a very good GS Series dedicated website with tech information.

Visit "www.bikebandit.com" to view microfiche parts on line. Once the site opens, click "OEM Parts" and select your model form the menus.

Respectfully,
Mark Shively