jetting issues (pictures added)

[FLY6584]

So I'm running the Factory Pipe Jetting recommendations for my setup (stock 701, bpipe, head(185psi), stock 38's, Carbon Tech LT reeds, stock flame arrestor(2 screens removed)), but I don't think they are correct.

The ski has always ran pretty good, but occasionally I would experience a low end stumble, but I never had the time to mess with it cuz I was only home for a couple days.

Anyways I was out the other day and had some time so I started adjusting my screw settings to see if I could get rid of that stumble and I have always suspected that I was lean anyways because my plugs have always been on the leaner side. Well I tried richening the high and low screws and it only got worse which doesn't make any sense.:dunno:

I'm running

135 mains
70 pilots
Stock N/S
95g springs
1.5 turns out on low and high speed screws

I know I am very rich on my low and high speed screws, but I was trying to be conservative because of how my plugs looked.

I've read through many threads and everyone says the Factory Pipe recommendations are spot on and then I occasionally come across someone with the same setup who got recommendations from Paul or Chucky and they always say the recommendations they got from Paul or Chucky were VERY different than FP recommendations.

I'd appreciate any advice. Someone suggested to me that I may have an airleak which is making my ski run so lean. I just don't understand if I'm running the FP recommendations with conservative screw settings why the ski would be running lean.

Thanks:biggthumpup:

By the way I'm pretty sure it's a lean bog because when it bogs I hit the primer and it comes back to life.

 

[B-Roy]

Im running pretty much the same set up

Mod Pipe
185 psi ADA
Stock flame arrestor


My carbs are rejetted 135, 75

And my adjustments are 1 on the low, and 1 on the high, and my ski runs great, and plugs look good too.

Oh Yeah, I have stock N/S and Spring too.

 

[FLY6584]

Im running pretty much the same set up

Mod Pipe
185 psi ADA
Stock flame arrestor


My carbs are rejetted 135, 75

And my adjustments are 1 on the low, and 1 on the high, and my ski runs great, and plugs look good too.

Oh Yeah, I have stock N/S and Spring too.

You're running the 115g spring?

Have you done a full throttle chop and checked your plugs?

 

[FLY6584]

I'm wondering if I should try a 72.5 Pilot?

 

[Matt_E]

Tune your low screw for highest idle, and nothing else.

If you still have hesitation, go to a 72.5 pilot.

 

[B-Roy]

You're running the 115g spring?

Have you done a full throttle chop and checked your plugs?

Yes, and theyre about perfect actually. :biggthumpup:

 

[#ZERO]

Dan… I thought you had the 72.5 pilot jets in you ski and removed them because you said it ran better with the 70 pilots? :banghead:

If you're trying to get rid of the sputtering on the bottom end, I would try a 115 gram pop-off springs with larger pilot jets, advance the timing three degrees, and fill your intake manifold crossover. All this should make the low end a bit crisper and more tunable.

 

[FLY6584]

Dan… I thought you had the 72.5 pilot jets in you ski and removed them because you said it ran better with the 70 pilots? :banghead:

If you're trying to get rid of the sputtering on the bottom end, I would try a 115 gram pop-off springs with larger pilot jets, advance the timing three degrees, and fill your intake manifold crossover. All this should make the low end a bit crisper and more tunable.

Nope we never tried the 72.5's. We tried the 75's and that's when it ran poorly.

I really don't want to advance the timing along with the MSD Enhancer and 185lbs of compression on pump gas. I just think you're playing with fire unless a professional like Chucky or Paul sets it up for you.

 

[FLY6584]

Anyways I went out today and ran it again with 2.5 turns out on the low speed and 3 turns out on the high speed and it ran a little better. The bog is occasional and very slight. 3 is the most you can turn out and have any affect right?

The plugs still look very lean though.

Would the fact that I'm running Klotz Benol affect how my plugs would look?

 

[marz831]

You want to be about 1 turn out on your screws, if you are 2.5 or 3, then you are jetted too lean...and yes, 3 is about the max you can turn

 

[felix5oh]

Try the 80g spring.

 

[FLY6584]

Well here are some pics of the spark plugs when I was attempting to tune the ski today.

These plugs are brand new by the way. How long should it take for the white porceline to change color and not be so white?

 

[FLY6584]

I know they are on the lean side, but how lean? Is that tan color you are looking for?

 

[WAB]

I think it's time for some new gloves :smile:

Removing the screens creates a slightly weaker popoff signal, I would think the lower tension CF reeds do the same. But I'm also terrible at tuning carbs.

 

[FLY6584]

I think it's time for some new gloves :smile:

No way dude I would never get rid of those gloves.:biggrin:

 

[FLY6584]

Removing the screens creates a slightly weaker popoff signal, I would think the lower tension CF reeds do the same. But I'm also terrible at tuning carbs.

The Factory Pipe recommendations are also based on aftermarket FA's so being that I am running a stock FA it should actually be rich.

Also I don't think the Carbon Techs do much. They're just more of a CF stock reed replacement.

 

[ROTATION]

80gm spring or some skis need 65gm

 

[Kaveman]

An airleak will cause a lean condition. Do a leakdown and verify that the engine is sealed properly. Because both plugs show the same condition, if you do have a leak look for something common to both cylinders such as the intake manifold, carbureter base gasket, exhaust manifold and head pipe to manifold gasket. If the engine is tight then proceed with tuning. If you are not well versed in carbs get yourself the book from Mikuni. It spells out how to tune carbs in a very methodical way. Most any shop should be able to get it for you from PU, WPS or Sudco.

 

[Matt_E]

Mikuni has it as a pdf on their web site.

 

[FLY6584]

but how lean do those plugs look?