rwilliamtaylor

89 JS 550 basically stock with just a K&N filter and rev limiter removed.

I just rebuilt the carb and put new pop off spring in it. The pop off pressure is 11 psi which should be fine, but I read in a post you have to lower it with a K&N.

What should it be lowered to?

Also, I opened the plug on the fly wheel cover and it was pressurized... Should there be pressure in there?

B.

rwilliamtaylor

Re: Js550 return line restrictor- solved!
I always read posts about the problem but rarely see a post that talks about what solved the problem... So here it is.

Turns out I had bad information. I was told that the pilot screw on the Mikuni BN44 was Air metering and when you backed the screw out it leaned the idle circuit... WRONG!

The pilot screw is fuel metering. Backing it out richens the mixture.

Final setting for the carb with 9psi pop off pressure

Idle screw set at 1 1/2 turns out
Pilot screw set at 2 1/2 turns out
Low speed screw at 1 1/4 turns out
High speed at 15/16 turns out

Starts right away and idles... This is on the hose... I haven't had it in the water yet, but at least it idles. I'll fine tune the settings in the water this weekend.

Thanks to jetskimechanic for the help.