Factory b pipe settings

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Dishman180

Location
Michigan
I have a 2002 yamaha superjet bone stock as far as the engine goes. Stock flame arrestor with 2 screens per side removed. I just installed a factory b pipe LIMITED. I did the 135/70 jets and am at 1.5 out on both low and high carb adjusments. Only 1 pisser and I have the top screw on the pipe 1 full turn out and the middle and bottom closed to start. Ski seems to run great and definitely more snappy. I do feel i could get more out of it while still being reliable. any one have pipe screw adjustments worth trying? Id like to leave the bottom screw alone cause it sucks to adjust. (I mainly recreational ride and rip bouys/ jump boat wakes here in Michigan) thanks for any input
 
fastgtfairlane

fastgtfairlane

Location
Charlotte, NC
I always set my skis up with parallel cooling meaning one line feeding the engine separately and one feeding the exhaust with the inlet on the bottom of the headpipe. I'll crack the bottom screw and open the top 1/2 to 1 turn. Also a flow control valve to the stinger will keep the waterbox from filling up with water at low rpms. It will also help build water pressure in the headpipe allowing the screws to spray instead of dribble. The cooler water directly from the pump will allow the headpipe to cool down quicker allowing more bottom end
 
S

Storbeck

Location
Minnesota
How about "advanced B pipe tuning"....super advanced stuff here....anybody have a target for b pipe header temp?

I'm going to guess (use a little Cunningham's law).

I bet Waxhead runs his pretty hot, because he's a high rpm guy.

FFGT runs parallel cooling which implies he probably runs cold water straight to the header, is it unrestricted? That would imply it's going to run very cool.

Zigler I don't know, but based on the lower screw opening I'll guess pretty cold (the logic is that if the water is colder you can use less) but at this point I'm really stretching.


Always amusing to me on some of these tuning threads, we have three answers here, all completely different, and probably all three work for the guys doing it. Multiple ways to skin a cat.
 
fastgtfairlane

fastgtfairlane

Location
Charlotte, NC
Yes I'm more of Freeride, boat chaser rider so I want the power to come on earlier for a stronger, low midrange. Cooler exhaust will have more bottom/midrange power. I have tried a restrictor on the outlet of the pipe when the water was cooler. During the summer in the south I run no restrictor usually. I used a drilled 2.0 seat and my restrictor
 
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waxhead

wannabe backflipper
Location
gold coast
john zigler said:
We run top and mid screws closed, and bottom from 1/8 to 1/4... IMO 3/4 is a lot.
Click to expand...
I agree it is, I actually run my a little less than that. But i will alway err on the side of safety with what I hand out online
My own one is 1/2.
My expecience shows me opening the top just kills power it does not give more down low.
This is based on my tunes however
I run a 4mm restrictor to the stinger off a tee that goes over board
 
fastgtfairlane

fastgtfairlane

Location
Charlotte, NC
theres really not one setting for all. you think 3/4 turn from closed is a lot. i have the top screw on my x2 open 1.5 turns and the mid 1/4 turn. actually ran better that way too. acceleration off the bottom picked up quite a bit. theoretically you can open the screws up enough till you notice a drop off in rpms on top then back the screw in a 1/4 turn.
the closer to the engine the water injects into the exhaust, the more dramatic affect it will have. i have almost always noticed a jump in low end using the top screw. i think its how you have your water line routed that would cause that. running a dedicated line to the pipe will also help the screws make a more dramatic affect because you can control the pipe temps better.
 
jetskidude1113

jetskidude1113

have
Location
West Hartford, CT
Mine is a buoy chaser and some wake jumping... best power for me is top close, mid close, bottom 3/8 out. I also don't have any luck opening the top, not even just a crack, looses everything and feel sluggish.
 
S

Storbeck

Location
Minnesota
Maybe the top screw thing is all about the pump setup? Kinda makes sense that if you are a little tight on the pump then top screw could help, if you are a little under propped then the top screw is moving power band down and you are blowing through it.
 
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