Service

SERVICE

Wheelie King

I am having a problem with unwanted acceleration on my 1983 Yamaha XT550. On several occasions, the bike has suddenly accelerated rapidly while in low gear— without my input! This heart-stopping maneuver occurs only after the bike has been restarted after a long ride on a hot day. I need your help as this causes some baaad wheelies in low gear.

Jim Barrett Lynchburg, Virginia

Yamaha's testing department informs us it has never experienced a problem such as yours on an XT550.

Your 550 uses a rather strange dual-carburetor system: The left carburetor is a CV-type with a vacuum diaphragm that opens the slide; the right carburetor is a mechanical unit that's operated by linkage. Both of these carburetors draw their fuel from a single fuel bowl on the primary, leftside carburetor. The left carburetor is in use all of the time, the right carburetor only comes into use from half to full throttle.

Chances are, your problem lies in the primary, left-side carburetor's CV diaphragm. If this is torn or damaged. it could slow the return of the slide or possibly hold the side in an open position momentarily.

The diaphragm is located at the top of the left carburetor, under a domeshaped cover. Replacement of the diaphragm would be good insurance. >

Banging ZX-10

I’m a 40-year-old street/sport rider with 23 years of riding experience, and a long-time Cycle World reader.

I owned a great 1986 Kawasaki Ninja 1000 that provided me with two years of reliable service, then I read your test of the new ZX-10, and made the mistake of buying one.

I’m a careful rider but I also like to go to the drags a couple of times a year for a little high-speed fun. My problem is a loud noise that comes from the rear hub if the clutch is suddenly released with the engine turning between 4000 and 6000 rpm. My dealer’s mechanic told me all ZX-l0s do this. And other owners of new ZX-l0s confirm the problem. Why didn’t Cycle World's test of the ZX-10 mention the problem?

I paid big bucks for an extended warranty, too, but it was a waste of money: Complaints to my dealer and Kawasaki Motors Inc. in California resulted in the same answer: Nothing is wrong and nothing can be done to correct the noise.

The Kawasaki representative even told me the ZX-10 was not intended to be ridden that way (at the dragstrip), it’s only a “canyon bike.”

If so, why do they sell the ZX-10 in the Midwest?

Larry Weenum Elk Grove, Illinois

Regardless of what you've been told, the ZX-10 isn V just a “canyon bike, " it's a great all-aroundsportbike. And our test ZX-10 didn't make any noise from the rear hub, even during our dragstrip testing. But a representative of Kawasaki confirms the problem does exist on some of the 1987 and 1988 models. And there is a fix. Some of the early ZX-10s had a rear cushdrive that was shaped incorrectly, resulting in the noise you hear. There was a recall on the effected models and you should have been notified by mail, which, evidently didn't happen. ZX10s with the updated cush-drive have a decal indicating so located on the inside of the right sidepanel.

The new cush-drive will eliminate the noise but need replacement on a regular basis if the bike is used at the drags often, according to Kawasaki.

You should contact your dealer so he can acquire the replacement parts from Kawasaki.