I herd that the carbs on a raptor have different jet sizes
Why?

 

Air- Fcr's come jetted the same on both sides from sudco.

I have noticed that running the same size jets on both side helps to even the exhaust temputure out, most i have seen are 50 degrees different from both sides.

But one side feeds 2 valves and the other feeds 1 is the reason, although you can take a trinity exhaust and seal off on side and the quad will still run. I used that as a example cause on day i removed the muffler and blocks off one pipe just to see. Trinity runs the headpipes seperate all the way to the muffler.
At least you have the lying down pat.[img]i/expressions/face-icon-small-blush.gif[/img] It just plain rips you that craycraft 686's can do you in. lol Maybe when you get back you will be able to adjust the chain properly.

[img]i/expressions/face-icon-small-wink.gif[/img]

 

Thanks a lot airraptor fpr the information
could you tell me what the stock jetting is in the carbs. Sorry about all the questions just want to know

 

Here is a good ATV connection picture with a mirror on top of piston showing valves.

engine cut away picture

 

the stock jet sizes are (sitting on the bike) left 140 right 145

 

Air- FCR's has a part number for the raptor in the sudco catalog, they come jetted 150, 150

A lot of people that run FCR's run identical jetting.

 

I realize that one carb feeds 2 valve and the other carb feeds one. Does that mean that the one carb that feeds the 2 valves flows more air also to keep the A/F mixture correct?

Seems to me that the one carb that feeds one valve should be the oversized valve. The carb that feeds the 2 valves is trying to keep air flowing through 2 valves and one being enlarged. Seems like the velocity may decrease alot through that carb. Just some thoughts. I'm going to have to think about this some more.