Kawasaki GPz550 Carburetor Suggestions

A couple of readers chime in on the Kawasaki GPz550 problem from the November/December 2019 issue.

Reader Contribution by Vincent Palazzo And Tom Batchelor
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by Keith Fellenstein

Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an email with “Keith’s Garage” as the subject.

Kawasaki GPz550 suggestions

A: It looks like I’m going to let my readers do the bulk of my work this issue. On the subject of the Kawasaki GPz550 from November/December 2019 issue, I heard from a few of you with helpful advice.

From: Vincent Palazzo. “It may not be carburetion. An ignition control module can fail in such a manner that you still get spark, but it won’t advance or retard. His bike is less sophisticated in that it still has a mechanical advance on the right crankshaft end. The weights and/or rotor may be rusted/stuck in the retarded position. Since it won’t rev, I’d be willing to bet spark timing is not advancing. This will cause all the symptoms Mr. Herchenroder noted.”

From: Tom Batchelor of Moto-Resto in Florida. “I think I have a suggestion for the other Keith (Keith Herchenroder) who wrote in about his GPz550 carb issue in the November/December 2019 Keith’s Garage column. I’m guessing you may still have his contact info. Please tell him he likely needs to shorten the CV carb diaphragm springs in regards to length. This was a mandatory operation on my Bandit 1200 Stage 2 setup from Holeshot Performance, and it’s required on a lot of other intake/exhaust modified CV carb bikes. Tell him I can’t give him an exact amount to cut them down to; however, what I’d do is start with 12mm off the length and try that; and go up to 25 mm. But I’d have to know the nominal length of the spring first to make an educated suggestion.”

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