The Zephyr Zone

New to the Zephyr, I have a 2000 kaw voyager and just took on this project bike. It is however a 550, 1991 and has been sitting for 12 yrs. servicing the carbs I find #1-#4 have a 108 main jet and #2-#3 have a 110 main. Whats up with this ?
I have been working on this for 2 months now. The brakes were shot from rotor to hand-lever , Its been a real pain to find parts and the clutch basket dampers were shot/brittle.
Jersey Gene

It is normal in in-line 4 cyl engine to have slightly different jettings in the outboard carbs than the inboard ones. The reason is the air intake is shorter and straighter to the inboard carbs.

Manufacturers did this to keep engines as lean as possible to pass emissions. These bikes are so old than some parts can only be obtained used, and sometimes you have to look into the old KZ550s, where their engines came from.

Finding parts is not a pain. It is fun.

My take is the designers set the jetting on the lean side for emissions reasons. As the 2 inner cylinders run hotter they can't go as lean as the outer cylinders.

What I said about the inner carbs and air intake, is not my take.. I have to say that. Did not come from me. I really don't know. I did not do any research.. Am simply repeating what the research labs of the companies selling the so called 'performance jet kits', like Factory Pro and DinoJet say for the difference in jettings. ...and I won't argue, it is there.


......and there is not doubt in my mind, if not for emissions (a very valid point, as we are loosing the planet), all carbs would have same jettings.

Hi voyager and welcome. Here is a link to the best place in the UK for Zephyr parts, yes I know its not in the US and I know that shipping to the US from the UK won't be cheap but its an option for any parts that you may not be able to find on your side of the pond.

https://www.kawasakioriginalparts.com/r ... country=US

After many hours and many repairs, the 550 fired right up. Rough Idle, at first, so the vacuum gauges went on a with just a slight turn on the balance between 1,2 and 3,4 it smoothed right out. The repair on the clutch damper went very well and having access to a abrasive water - jet machine the damper rubber ( neoprene ) pads were a snap to manufacture. However I had read many a post on tapping threads to hold the basket and gear back on. Not liking that so much I manufactured my own rivets using high carbon steel rod and turning to size on my lathe. What a difference in sound now.
So I will be out on the road with this one soon. For a barn find from 1991 its a sound and dependable bike now.
thanks again for the links and the many posts I have read on this forum
Gene K