Dual 44 Mikuni observations

[freestylegeek]

i would drop your pop off

I might be trying that next.

After talking to Paul, I might just have some carbs that aren't going to work for my appllication.
I'm going to check and see if the needle on the screw was over tightend and has a groove cut into it.
If that's not the case, it might be ebay time. :frown: :frown: :frown:

 

[waxhead]

????
i am confused that you cant get the 44s working on there

But have you made sure they are a matched pair ????

chack the carb numbers if you dont have a matched pair then you will be chasing your tail on the setup

 

[Freestyleriverrat]

full specs baby :biggthumpup:

 

[Matt_E]

i would drop your pop off

Even though I personally don't like the low popoff (ON MY SKI!!!) I would give it a try (I did!) to see what you can come up with. There's more than one good carb setup out there, and it pays to spend the time to find em for your boat.

 

[freestylegeek]

????
i am confused that you cant get the 44s working on there

But have you made sure they are a matched pair ????

chack the carb numbers if you dont have a matched pair then you will be chasing your tail on the setup

They are a matched OEM pair from a waveblasterII.
Front carb:
7
1 1

64x
01


Rear carb:
7
1 1

64x
02



we're having fun now!!:bs2:

 

[freestylegeek]

full specs baby :biggthumpup:

You mean "full specs - OR - baby".

I have 3 babies, so full specs are DEFINITLY not a choice. :cool2:

 

[freestylegeek]

Even though I personally don't like the low popoff (ON MY SKI!!!) I would give it a try (I did!) to see what you can come up with. There's more than one good carb setup out there, and it pays to spend the time to find em for your boat.

Lowering the pop-off is A LOT cheaper than buying new carbs, so it's worth a shot to me.

 

[Matt_E]

Yep....tuning carbs is a pain in the ass, but worth the time spent. You want to get the most out of your motor. Don't shortchange yourself on tuning the carbs.

Remember, lower popoff can be compensated with a smaller low speed jet, and vice versa.

 

[x-jetter]

did you ever figure out what was causing you to have to give it throttle every time you started it? i'm having similar issues with my 44's, where i have to prime it to cold start it on the lift, and then when i put it into the water i have to completely floor it to get it started, then it runs real crappy for about 15 seconds then it's fine.

 

[freestylegeek]

did you ever figure out what was causing you to have to give it throttle every time you started it? i'm having similar issues with my 44's, where i have to prime it to cold start it on the lift, and then when i put it into the water i have to completely floor it to get it started, then it runs real crappy for about 15 seconds then it's fine.

that's what I'm trying to figure out right now.
I have to be 2 turns out in order for it to start without giving it throttle.
Aperently, I'm not creating enough suction for the fuel to get through the low speed adjuster when the throttle plates are closed.

Have you tried turning out your low speed adjusters to see if that fixes the problem?

 

[waxhead]

here is the setting i ran in my 701 limited engine
120 low
17psi pop off
100 high

My ported 760
115 low
100 high
15psi pop off

I am not that helps
but try it and let me know
I have always had good results with these carbs

 

[Big Kahuna]

hey Matt, try a much larger low speed jet........... if you are at 2 turns out, and it is acting like you need more, make them larger.......... You remember when I had my cylinders ported with the OEM 38's............ everybody was running 75 lows and 135 ( I think that the highspeed size, been a while!)....... well, the only setup that would work was 105 lows............. That is just what my porting and setup required......... Guess what, a buddy had the same porting (TLR) same carb setup with a Dry Pipe, guess what jetting............. Yup 105 lows............. neither of ours would run with STD Jetting specs that everybody else was running!!!!!!!!!!!

Oh, at Lanier, John (your buddy) said try 80 lows ( I was having some carb issues (Turned out to be a crack in one of the carbs- I sold them right after that and found out that they had a crack).......... Ran good for a minute........... Then it was #5 rebuild for the year (2003).......


Every setup is different............. Freestyle motors are ment to have lots of power down low, so they will need more fuel...........

I am leaving in the morning, actually at work (3:45 am), have a funeral to go to, when I get back Sunday, I will try to remove my carbs and check jetting........

 

[x-jetter]

Have you tried turning out your low speed adjusters to see if that fixes the problem?

not yet, i was wondering if i need to change popoff, because i'm running a 2.3 n/s with a 115g spring. so i'm gonna lower that and see what happens first.

 

[SUPERTUNE]

Why are you using B2 stock carbs? More than likley $$
Most OEM carbs are WAY different than the aftermarket mikuni's, things like throttle valve angle (the # stamped on butterfly) most of the low speed screws are a different finer thread pitch, hence this is why you can't run them (2-1/2 - 3 turns out) closer to what the aftermarket runs (1-1/2 - 2 turns out) and the most important issue is oem's are made for fuel economy and have fewer low speed suppy holes in the throttle bore, different sizes and staggered with broader spacing. In a nut shell... most of the advice you are getting from others that are running the std aftermarket 44mm's won't work for you!! I wish I could help you with some spec's. My complete freestyle carb set-up has to be done with the aftermarket ones, my choice is always use 46mm's even on 701cc motors, Buy them once and you will be able keep them for all of your upgrades all the way up to 820-860cc motors (5 and 6mm strokers + 85-86mm bores).

 

[waxhead]

the setting i am giving you are for oem 760 carbs by the way

 

[SuperJETT]

He has gone from 115 to 130 lows and it didn't change a think, also several popoff combinations.

hey Matt, try a much larger low speed jet........... if you are at 2 turns out, and it is acting like you need more, make them larger.......... You remember when I had my cylinders ported with the OEM 38's............ everybody was running 75 lows and 135 ( I think that the highspeed size, been a while!)....... well, the only setup that would work was 105 lows............. That is just what my porting and setup required......... Guess what, a buddy had the same porting (TLR) same carb setup with a Dry Pipe, guess what jetting............. Yup 105 lows............. neither of ours would run with STD Jetting specs that everybody else was running!!!!!!!!!!!

Oh, at Lanier, John (your buddy) said try 80 lows ( I was having some carb issues (Turned out to be a crack in one of the carbs- I sold them right after that and found out that they had a crack).......... Ran good for a minute........... Then it was #5 rebuild for the year (2003).......


Every setup is different............. Freestyle motors are ment to have lots of power down low, so they will need more fuel...........

I am leaving in the morning, actually at work (3:45 am), have a funeral to go to, when I get back Sunday, I will try to remove my carbs and check jetting........

 

[freestylegeek]

Why are you using B2 stock carbs? More than likley $$
Most OEM carbs are WAY different than the aftermarket mikuni's, things like throttle valve angle (the # stamped on butterfly) most of the low speed screws are a different finer thread pitch, hence this is why you can't run them (2-1/2 - 3 turns out) closer to what the aftermarket runs (1-1/2 - 2 turns out) and the most important issue is oem's are made for fuel economy and have fewer low speed suppy holes in the throttle bore, different sizes and staggered with broader spacing. In a nut shell... most of the advice you are getting from others that are running the std aftermarket 44mm's won't work for you!! I wish I could help you with some spec's. My complete freestyle carb set-up has to be done with the aftermarket ones, my choice is always use 46mm's even on 701cc motors, Buy them once and you will be able keep them for all of your upgrades all the way up to 820-860cc motors (5 and 6mm strokers + 85-86mm bores).

Well, it wasn't really for the money.
Paul highly recomended OEM 44's for my stock stroke Lamey motor.
He has had very good success with them on other motors set up the same way.

BUT, I also know that you have had GREAT success with Mikuni 46's on a whole bunch of different motors (from Pat's MONSTER stroker to Abe's 720 [that I built]).
I may have to give you a call sometime to go over it in detail.
I understand what you're saying about the thread pitch, because I just looked at them last night, and it is DEFINITLY a fine thread.
Especially compared to the low speed screws on my 38's.

So maybe I'm not in that bad of shape having to run at 2 turns out(?)

You've got the wheels turning in my head now.

 

[freestylegeek]

...My ported 760
115 low
100 high
15psi pop off...

That seems to be the direction I am heading.
I may be able to try that this weekend.

 

[Mark44]

One thought.
My 44's on my ported magoo motor seem to respond much better with a little more restriction. I tuned them and then played with screens on the inlet of my stock flame arrestor and found that running two screens worked the best for me, must be allowing the carbs to get a better signal with the restriction. Just a thought and a fun thing to play with.

Mark44

My set up as of now on new SBN 44's
112.5 H
117.5 L
2.0 NS
95G
2 screens for restriction on incoming air

 

[waxhead]

if thats the case then take the restrictor out and go up a jet size on the highs