Super Jet B-Pipe Carb tuning- stock SN 701 HELP

Fleabags

Fleabags

Location
Michigan
Hey guys. I know this topic has many posts, however, I couldn't find one that answers my questions. I'm hoping someone has had a similar experience and can provide some insight.

I have a 1995 SN (701). As far as the engine goes, it is all stock and very low hours. I just installed a B-pipe (limited) and set it up to the Factory Pipe specs -

Main Jet : 145
Pilot Jet : 120
High speed screw : 1 1/2 turns out from closed
Low speed screw : 2 1/2 turns out from closed
Needle & Seat : Stock
Spring : 95 gram

It ran pretty decent during my initial test ride but was running rich. I tied it to the trailer and dialed in the low jet. The highest rpm at idle was at about 1 1/2 turns out (not 2 1/2 as FP suggests). The pipe adds noticeable power, however, I am still running very rich. Turning the low screw in more, doesn't seem to help. The ski ran flawlessly before adding the pipe. The ski is very rideable, just not quite right. The exhaust exit shows that it is rich since it is all black on the back of the ski.

Mid to full throttle it pulls hard. When running about 1/4 - 1/3 throttle, it seems to kind of gurgle. However, doesn't hesitate or bog when I snap the throttle. Just not as snappy as it should be. It is particularly noticeable when setting up to jump a wave.

Should I be dropping down a size on my pilot jet? I would have thought that the jet sizes would be right on since I have a stock machine and FP provides jetting specs for a stock ski.

BTW, the pipe screws are set up with top and mid closed and bottom open 1/2 turn - FP recommended settings.

THANKS
 
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pepperson4

pepperson4

Location
IL/WIS border
bump, same problem. just installed my limited pipe on a stock 701. the ski rips past half, but from idle its really laggy, and sometimes wnats to cut out, but once it clears up it rips! hellllllllllp us!!!! sorry for the jack lol
 
btmboards

btmboards

Brett
Location
Oceanside, Ca
Yep^^^ what do you have for water restriction going to the stinger, also what carb do you have, single 44? If so the FP specs are a bit on the rich side for both high and low screws.
 
Fleabags

Fleabags

Location
Michigan
Thanks for the comments. I have single cooling and no restriction to the stinger. The set-up is per FP.I have the stock SBN 44 with stock FA. The choke has been removed (primer).
 
Fleabags

Fleabags

Location
Michigan
Below is the response from FP.
I'll give it a try and post results.

FP Response:
Our jetting should be pretty close as long as you are not at elevation. We can't advise you on jetting but there is a Mikuni article on our site that might help. Closing the bottom headpipe screw and opening the top screw 3/4 of a turn may work better for you.
Throw water on the pipe, as described in the instructions, to fine tune this adjustment.
http://www.factorypipe.com/t_carbtuning.php
 
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Fleabags

Fleabags

Location
Michigan
Still need to get out and test it - work keeps getting in the way.
However, it is running so rich, I would be surprised if closing the bottom screw and opening the top would completely solve the issue.
 
lazyt747

lazyt747

Cool Beanz
Location
MI
Do both the flow restricter and closing the bottom two headpipe screws along with the 1/2-3/4 opening of the top. Should do the trick.
 
btmboards

btmboards

Brett
Location
Oceanside, Ca
I ride nothing but in the ocean and you have the same setup as me.
I have my bottom screw completely closed of top is I think about 3/4 middle is about the same I think. Even this is colder than FP recommends but it works good. If you ever want good hit you need some sort of restricter before the stinker. most use a jetworks flow control. I am too cheap so I use 4mm reducer pills in my lines. otherwise your waterbox and stinger will fill with water too much and your motor has a yard time pushing it out before getting that pop that you want.
Also my top my screws are set at (i think) L 1.5-2 and H 3/4
 
Fleabags

Fleabags

Location
Michigan
Thanks for all the help.
Sounds like I have several things to try. I have an inline (ball valve) flow restrictor that I can take off of my JS550. I'll play with that as well.

Brandox2 -
your post: Im a little confused after looking at factory pipes carb suggestions. is it 1.5 on highspeed and 2.5 on low?
YES, the carb settings you stated are correct. FP recommended set-up is 1.5 on High speed screw and 2.5 on Low (pilot) screw - SINGLE 44 SBN
 
Fleabags

Fleabags

Location
Michigan
I thought I would provide an update in case anyone was interested.
I set-up the Pipe for low-end as FP suggested - I closed bottom and middle screws and opened top 3/4 turn.
The mid range gurgle that I was experiencing subsided, but didn't completely go away. I played with the pilot screw a bit and overall the ski was very ride-able. The amount of black residue (running rich) around the exhaust exit was reduced as well.
I'll have to continue to experiment and try other carb settings and/or jetting.

My goal was to boast performance but still maintain a well running machine that anyone could jump on a ride. At this point, I am not to that point.
 
Lighthouse13

Lighthouse13

Location
Northern, VA
There is definitly no standard way to have it all set. I installed a adjustable FCV and a bpipe, had the top screw open 3/4ths and the others closed and my whole pipe sizzled. I opened the bottom 1/8th - 1/4th and the whole pipe was still sizzling. It's just a matter of messing with it until it works right on your ski. I ordered the thandles from jetmaniac so i could change the bpipe and carb settings easier while riding/tuning.
 
jhammett89

jhammett89

Location
Mass
I haven't got my pipe to sizzle even with screws barely open but it might have something to do with the New England water temps this time of year but it hits good around 1/2 turn on the top
 
Lighthouse13

Lighthouse13

Location
Northern, VA
The pipe should sizzle out to 4" from the head pipe. That is when it is properly tuned. So I would adjust until you get there.

ANd yesit can be ultra frustrating getting it dialed in, only to have to change it for the seasons and drastic differences with water temps, lol.
 
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