Super Jet Superjet Carb

jnitchoff

jnitchoff

Location
Lemont, Il
I put the factory pipe on my superjet and it is running like crap. I tuned the head pipe and still nothing. I think its the carb. I put 135 main and left pilot the same. I think i need to adjust the high speed screw, low speed screw, and pop off. I have no idea where these are on the carb. Can someone please tell me where they are. Thanks
 
schicks

schicks

Karma Enforcer
Location
West Michigan
the pop off is dtermined by the combination of your n/s size and what spring you are running. The mikuni manual explains what the different combos will give you. The low speed adj needle in the lowest one on the carb body and the high speed is the adj needle that sit near the top of the carb. turning clockwise leans it out and turning them CCW richens the mixture. Adding a b-pipe should not require a change in pop off pressure
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
Define crap. All the time? Just when you get on the throttle? When you squeeze the throttle soft or hard? Be more descriptive on what crap is. There are a lot of parts to a motor and vague doesn't help narrow it down.

Screws will make the ski run less than perfect but not "like crap". It can run "okay but not great" with everything working right and bad screw settings.

Here are the jetting specs for a B-pipe on a stock motor... http://factorypipe.com/media/instructions/yamaha/701SJ03.pdf

Main Jet: 135 (130 stock)
Pilot Jet: 70 (stock)
High speed screw: 1 2 turns out from closed
Low speed screw: 1 1/4 turns out form closed
Needle & Seat: stock (55 psi)
Spring: Stock (95 gram)



Set the carbs to the specs provided by FPP. It may have a slight hesitation but it will run good overall. If not, you probably have another issue. Clean and test your carbs. Put in new plugs. Ensure the fuel system is clean, etc. Then worry about jetting when it works kind of right.

PS. Stock pop-off is 53 with 1.5 N&S with 115gr spring. Not sure why FPP says 95 gr spring.
 
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