Jets sizes ... what do they mean?

[ski]

I see by the jetting charts my Vmax uses 151.3 main jets

My friend runs a ZR900 and his sled uses 440 main jets..... now I know his are measured in thousands of an inch, I assume mine are some metric number, or by flow characteristics, but can i use standard type jets in my sled? And how do the numbers cross over?

 

[mrviper700]

No, the jets dont interchange. For one a round slide carbs uses differnt jets because a flatslide carb pulls more fuel then a roundslide does because of the slide area. Second the round style main jets use a differnt numbering system, you can get a mikuni slide rule thru hi-performance engineering and it will convert a round main to a hex main number.

 

[ski]

That is odd because the ZR uses flat slide carbs as well .... alot bigger but still flat slides... it is a 2003 model maybe the olde rones didn't. My other buddies Polaris XC500 uses the bigger number for the jets too and it is also a flatslide, Now I'm more confused

 

[bluehammer]

You're correct in what you say about Arctic slide carbs. I thinkin' that Yamaha uses their own main jet numbers and will not fit other brands. Also not all pilot jets are interchangeable between brands. Some yes, some no. Likewise the standard 440(example) main will not fit Yamaha. Get the jet conversion chart like Donnie says above and then you will know what you're looking at when doing comparisons.

 

[mrviper700]

ok, lets make this simple

but each manufacture has their own carb specs, for example, a 2000 thundercat has flatslide mikuni carb rack, so does a yamaha,BUT, the thundercat uses a starter jet, and also has both fuel and air screws, they also run a #35 pilot jet and a 320 main jet. You see every sled company has specs and the carb manufacture simply builds what they want, even tho the manufacture makes the same thing for someone else, they dont interchange, the style of the pilot jet is all together differnt and so is the numbering system. mikuni makes many differnt models of carbs, and the parts dont interchange, so does kehin, etc.

Polaris mostly use Kehin carbs, both flat and round style, even "D" slide carbs

 

[ski]

ok thanks Guys