Thank you very much SP700racer. [img]i/expressions/face-icon-small-smile.gif[/img]

I'm currently running 6 vents, and I'm at 700 some odd feet above sea level(according to the topo map) I took it out yesterday to find that looking at the plug it seems to be running pretty lean. The porcelin as well as metal arm are burned clean(clean metal, and almost white porcelin). Unfortunately my dealership does not have any main jets in stock, so I had them order some 155's and 160's.

I'm alittle mythed by four stoke jetting. I could tell on my 2 strokes because they would fart and pop when not jetted right, but My pred felt/sounded fine. No backfire on decel, no hesitation on exceleration, and it jumps when I stab the throttle quickly. Guess I'll just tinker till I get that nice tan color on the plug again....

 

I feel your pain in getting the jetting figured out. It's alot of trial and error. I would start around 170 and work my way back. When you cut the spring the slide will open quicker and create a bog if you don't up the pilot jet. Good luck, and remember just when you get it right it's going to warm up outside then we get to re-jet again.

 

I am running my with alot of mods and have a stock pilot and 170 main and runs pretty good

 

Fidge, when you run a clamp on filter, you do not see the benefits of the spring mod. Thats why your running good with the stock pilot jet. Run the factory airbox, up your pilot, and you will pick
up some low and mid power. The factory carb makes the best power with an airbox. When you change to Lectron or FCR or edelbrock carb the Hot seat or Rath kits work the best. But you need the snorkle for any carb to make the most power, clamp on's will cost you 2 to 3 hp on the low end.

 

I can not use a factory airbox becuase my twin pipes run through there that is why i had to put the clamp on... Do you really think ill lose 3 hp bottom end

 

Yes you will lose power with a clamp on and stock carb.. you need vaccum to keep the slide open...

 

what do you suggest i do since i cant put an airbox in buy a carb???

 

I remember hearing that you can cut the spring that controls the slide.. The DS guys have the same problem, hit the bombardier forum they can tell ya exactly what to do...

 

I have dyno tested the stock carb with clamp on vs stock air box w/airforce kit vs filter on snorkle.
the clamp on lose's power compared to the other set ups. stock with airforce makes best power with stock carb but makes less power with aftermarket carb. You need some type of pipe between
the carb and filter to create velocity and smooth out the airflow before the carb. It will come out
of the hole better or out of a turn quicker.

 

Fidge check your PM