Tuning dual 44's - couple of questions

[Mark44]

Yes Blaster these are the carbs from you.

The reason I want to try the 115 gram is because as I increased the pop from 18 to 29 it greatly improved the performance of the motor and removed 80% of my hesitation. 115 gram may take it to high but I need to run that spring to make sure then come back down if necessary I have seen to many cylinders go to waist when people think there ski is running its best then just quit tuning and don’t jet up just to verify the settings. I won’t mention any names SXR-L@@........


Just my thought process........

Mark44

 

[wildman326]

Soooo, I had some 44s and thought they were great until . . . another rider that I look up to very much told me that he was running 46s, and "They were the best carbs he'd ever had." He'd been into freestyle much longer than I and had tried every carb out there (except Full Spect.)

He had them set up with 112.5 pilots, 107.5 mains, 2.3 NS and 65 gram springs, return drilled out with 70 jet in the return, 14psi pop off, and doubled up clear fingernail valve things. I searched high and low and finally got a set of 46's and set them up the same way and have ran them for about 2 years now.

Well, he calls me the other day and says "You'll never believe it." "Tell me." I replied. He proceeded to explain that he was wrong all this time. Apparently he'd sent them to be re-built and had been informed that they were 44s. To me that was kinda like finding out I'm really an orphan. :bs2: What I'd have believed for some time is not "real." Not wanting to be different, I decided to get on the bandwagon and got myself another set of 44s.

Here's the dilema. We used to run them with 120 pilots, 110 mains, 1.5 NS, and 95 gm spring - and that was great. He's running the above-mentioned set-up. My notes from Paul say 120 pilot, 95 main, 2.0 NS, and 95 gram spring. I'm pretty sure I've got all the necessary stuff to set them up any of the 3 ways, but I'm not sure what to do . . .

I guess I'll try Paul's suggestion first.

Any thoughts?

 

[keefer]

If you lower the pop off pressure, the transition from 1/4 to 1/2 throttle circuit will effectively become richer. If the pop off is too low you will find that the vibration from the engine can cause fuel to dribble and cause problems with getting it to run cleanly. I run my pop at about 22-24 lbs and it seems to run the best. I can usually compensate with different jets if needed. I used to run reverse jetting like is being suggested to you but I changed back to forward jetting as per Pauls suggestion. It seems to run alot cleaner off the bottom and it has reduced that going rich event when the boat lands with the pump side of the carbs down situation.

61x @84mm ported & polished exhaust
62t cases ported
B Pipe Mod chamber
205lbs compression with stock timing on MSD enhancer
Mikuni 46mm with Riva adapters & Prok flame arrestors
R&D manifold & Riva spacer plate
Boyesen carbon reeds
Pilot Jet = 120
Main Jet = 127.5
N/S = 2.0 with 95g spring
Pop off = 22lbs
Low speed screw 1.25
High speed screw 1.25

 

[freestylegeek]

...I changed back to forward jetting as per Pauls suggestion. It seems to run alot cleaner off the bottom and it has reduced that going rich event when the boat lands with the pump side of the carbs down situation...
Pilot Jet = 120
Main Jet = 127.5
N/S = 2.0 with 95g spring
Pop off = 22lbs
...

I have a feeling I will end up VERY close to this (maybe a little higher on the main jet.)

It's almost one of those things where you need to ride the boat in order to recomend the correct jetting.
Paul has a TOUGH job trying to give recomendations over the phone - I do not envy him! :bigeyes:

 

[waxhead]

a 127 high is very rich
i am suprised you are not having issues with the ski not reving using the 127.5 high
inormally run a 100 high in my set up close to what you are describing here

then again i would not run a pop off pressure so high ethier

 

[keefer]

That is the jetting Paul suggested, actually it is only 5 points leaner total jetting than when I had it reverse jetted. The boat carburets clean from bottom to top. It is in no way too rich, the plugs read light tan. Babys got a big appetite.:biggrin:

 

[waxhead]

paul said to run a 127.5 high

 

[keefer]

Yup, thats what is currently installed and runs great.

 

[Ottis]

Did any of you guys hear about there being a differance in jetting with manifolds that have crossover tubes (stock b2) and ones that don't(aftermarket,like the riva)

 

[Ottis]

if thats true that would make a differance in comparing jetting from one to another

 

[Matt_E]

I just got back from being out the first time this year. It ran horrible. :frown:
It loaded up like crazy from the bottom, and took at least 2 to 3 seconds to clear out and take off. Crazy rich I guess.
Turning the low speed adjuster from 1-1/2 out to 1/2 out made it slightly better.

After getting home, I took off the carbs - I am running 122.5 mains and 125 pilots, 2.0 N&S, and 95g spring (24 psi popoff).
(I thought it was 120 mains and 122.5 pilots)

Anyways...I am a bit puzzled as to why this setup ran well the last few hours I ran it last season.

The motor is a bit different now - more extensive porting, 180psi instead of 190 psi, stock F/As with one screen (instead of K&N filters), bigger bore.

I am stumped - I guess I'll have to wait on my jets and retry.

 

[wildman326]

I spent all day yesterday finishing up my new super fancy pants intake.

It's stock with:
crossover filled in
bottom and sides filled in to match
reed stuffers on
Kawi reed cages with
Special "stroker" CF reeds and a
1/4 spacer plate

Next I set up some 44s like this:

2.3 NS
65 gram spring
112.5 Pilot
102.5 Main
Doubled Fingernail thingies
70 Restricter in return

And man does it hit hard! Way crisp!

I had a few hic-ups in the process, but I'm very pleased now!

I tried the 2.0 NS 95 spring with 120 low and 95 high and it didin't work very well, so I plan to try it without the fancy intake.

 

[Matt_E]

Give us some details on the motor.

 

[wildman326]

OK.

61x cyl at 81.5mm, Ported - widened to Xmm (I don't have my porting journal here), transfers cleaned up, lower sleeve sides raised 13mm, intake roughed up,

T cases, finger ported and filled in so high only Kawi reeds will fit

Stock electrics w/ MSD enhancer

limited B pipe matched to cylinder and opened to 46.5 or 47mm at round juncture - jetworks valve at stinger

ADA 180 lbs comp

stock dual 44s w/ stock arrestors - I haven't drilled out the returns, but probably will later this week.

Now I should say that the only reason I did the kawi thing is that a while back it seemed like a good idea and so I filled in the cases so that only kawi reeds would fit. I wish I hadn't and the next time that motor is out of the ski I may grind down the jb weld so that any reeds will work. I tried this set-up before with 46s and stock kawi reeds and it ran like crap, so I took it apart and ran different cases. However, now that the set-up is put together as it was initially described to me instead of different it seems to run very nice.

 

[waxhead]

I spent all day yesterday finishing up my new super fancy pants intake.

It's stock with:
crossover filled in
bottom and sides filled in to match
reed stuffers on
Kawi reed cages with
Special "stroker" CF reeds and a
1/4 spacer plate

Next I set up some 44s like this:

2.3 NS
65 gram spring
112.5 Pilot
102.5 Main
Doubled Fingernail thingies
70 Restricter in return

And man does it hit hard! Way crisp!

I had a few hic-ups in the process, but I'm very pleased now!

I tried the 2.0 NS 95 spring with 120 low and 95 high and it didin't work very well, so I plan to try it without the fancy intake.

now you are talking

try 120 lows
105 highs
15-16 psi pop off
and 1 turn out on high and low screws

 

[Matt_E]

I got 125 lows, and it is wayyyy too rich. Of course, I don't have that intake setup.
My intake is not filled with epoxy. Cases are ported though.

 

[waxhead]

bearing in miond he is running very low pop off with the 63 gram spring he will go a little leaner when he goes up to an 80 gram spring to get his 15psi pop off
i have fitted alot of 44s with b-pipes and this setting always seems to work very well
and doesnt need to be changed much to get it perfect if it isnt already

 

[Matt_E]

Are you thinking I should lower the popoff? (24 psi, 2.0/95g right now)

 

[waxhead]

im getting confused we are talking about 2 different setups here

i was talking about wildman

i would still try the setup i gave you
120 low
100 high
15-16 psi pop off
2.3n/s with 80 gram spring

so yes i think you should lower the pop off and also reduce the size of the low speed jet
1 turn out top and bottom

 

[Matt_E]

Tell you what Jared...I got some jets coming to me in the mail tomorrow that I want to try first. I will, however, order some other sizes and some springs.
I will try both setups.
My motor has a lot of potential, and I would hate to see it wasted in me being lazy tuning the carbs.