701 b pipe carb tuning

[Skimour]

So my ski runs good, but feel like its a little loaded up when I'm done riding and the plugs are dark. Motor is all stock and I started with my carb settings according to factory pipe settings as a starting point. I've gone way In from what they said. My lows are 1/2 turn out and my highs are at 1. Like I said runs good, but I don't think I'm getting all the power. Any thoughts? Also if it helps I have the 1 pulse line style

Stock 701, b pipe, dual 38 61x/62t with am filters

 

[shaunsteezy]

put a jetworks flow control valve on the line into your stinger. made a huge improvement on my set up

 

[Quinc]

Easiest way is to hook up a Tach and verify that you are getting your max RPM's for the pipe and adjust the screws and jetting until you are.

 

[Blue]

Did you rejet the carbs?? Typically you will need to replace the 70 pilot jet with a 75 change the springs and replace the main jet from a 130 to a 135. Especially with AM Flame arrestors. It wont make power without extra fuel.

 

[Skimour]

Shaun, I got one in there.

And I already rejected it to what factory pipe says which is 135 and 70. My ski is rich without a doubt not lean so a 75 jet wouldn't make sense to me?

 

[Blue]

The 75 will not richen it much but the extra fuel on the bottom keeps the engine rich enough on the bottom that it doesnt run away when you start it on the trailer or jump out of the water. Make sure your not putting to much water in the pipe too. We use 1/2 turn on top of the headpipe and 1/2 turn on thebottom of the headpipe. The flow control valve helps alot. Is ur compression good? Stock head should be 155psi.

 

[Skimour]

155 compression. I might have a little too much water in the pipe, I'll double check my pipe settings. I'd like to not richer it at all (go to 75) since it loads up through the no wakes zones and it def does not run away on the trailer or in the air

 

[Little_Franny]

What spring for the needle and seat? Im guessing your popoff is too low, I would run the 115 g spring with a 1.5 N/s and the 75/135 jets as a good start point, start with screws 3/4 low and 1 high

 

[Pro-pulsion]

Your lift tabs for the needle valve may be too high as well holding the needle valve open for too long. They should be flush to the top of the little formed area around them.

 

[JetManiac]

Shaun, I got one in there.

And I already rejected it to what factory pipe says which is 135 and 70. My ski is rich without a doubt not lean so a 75 jet wouldn't make sense to me?

Factory pipe settings are for a stock ski with a pipe only. They state in the instructions that they are a guideline starting point only. Their settings were developed back in the day circa 1996 for rec riding not freestyle. We like much more fuel down low than their specs.

What other mods do you have? Head, enhancer, etc.?

A/m flame arrestors need lower than stock popoff as well.

 

[Vumad]

How do you know its rich at 70? Rich and lean can feel a lot alike.

I stuck a piston wot at 75/135@40 (it is possible I had a case leak). I'm at 75/140@18 (setup that way by bad boys racing) and it's the cleanest throttle response of any ski I have ever ridden. It gets a little rich if the surf is too rough but most boats sitting in a low RPM do, which I'm sure that's why you see a lot of throttle blipping in the surf.

Stock airbox, dual stage reeds, b-pipe, 170 psi, lighten flywheel, 12/17 prop, flow control valve.