I am working on this 900 rickman kawasaki and 3 of the mikuni carbs have 113 jets and the #1 has a 115. Anyone know why that would be? If there is no reason what size jets should I run?

 

In my 86 gpz900 manual, 135 mains were used on all 4of the cvk34mm carbs. I also run all 4 mains the same on my 90 zx7. So I am not sure on the different size on #1 especially.

 

I had an old bike that ran #1 richer. #1 on that ride was the stress side with the chain etc. So the theory was that running that cyl richer would keep it cooler.

 

Interesting theory. Maybe to compensate for ppoor engineering?

 

lol..maybe so Drag...I've seen guys run a different heat range on the center plug racing ol' triples on the same theory. Prob same kind of theory as a pro ball player not changing socks. LOL

 

I am fully aware of the middle cylinders on the H2 triples running a richer jet and cooler plug to prevent seizures of the middle cylinder. I cannot see that theory on the 900. None of the 900 or 1000cc books that I have mention running richer on the #1

 

I bet in this case, it was a previous owner that bought a jet. The 70's Rickmans had 5 or 6 different option sizes on the jets, Usually it was a 112.5 instead of a 113. But the 115 was an option also.

 

and on jet sizing for that thing there was5 different options. 110, 112.5, 115, 117.5 and 120. How did the plug look on the 115 cylinder you have? and on the 113?

 

and if you have a tester and are bored, lol, pull compression on all the cylinders. YOu don't see many of those old road rracers around anymore. You got a pic of that thing? Still have that huge bubble windscreen? lol

 

Thanks for the help guys. The first time my new guy ran a compression test the #'s were all over the place. After showing him he needed to open the throttle to do it correctly they are all right around 120. The carbs are 128mm sodoes changing them all to 113 jets sound right . Thats right in the middle. I have some pics. I will post them as soon as I get near my camera.