Dual 44 Mikuni observations

[douglee25]

If you NOT using 62T cases and using 61x cases, Use the Wetjet 46mm carb complete w/manifold! That Wetjet set-up will work very well when you can find them.

Roger that. :biggthumpup:

Doug

 

[SkiDaddy]

Chris, AND the rest of you that are trying to use the stock OEM carbs are very hard to tune for FREESTYLE throttle hit! (remember Yamaha made them for fuel ECONOMY and some added performance) Just sell them stock 760 carbs and buy some new 46mm's, freestyle motors require FUEL to have throttle response and stock 760 carbs WON'T cut it without a total circuit rework!!
Do you see any of the aftermarket carb guys building race carbs out of stockers, not much. Most Novi's, All of Full Spectrums and I think all of the Jetworks Blackjacks also use the aftermarket mikuni's for a base carb. How much is it worth to you to pay for an update re-circuit work on your OEM yamaha carbs, Just need to know if it would be worth my time to develop 760 carbs for this...

P.S. This is MY opinion only...I do NOT claim to know it all, I just know what work's for my engines...

I would pay $75 for a circuit rework if it made a big difference. OR would do it myself if I had the data.urr:

 

[#ZERO]

I'd pay a hundred bucks if I thought it would fix the problem.

I think I'm going to try some different pop off pressure combos before I go with aftermarket carbs.

 

[SkiDaddy]

AM carbs are waaaaay $$$$.

 

[michael950]

Chuck isn't even recommending the Riva Powerbombs ($1000) or Full Specs ($1200). Just get the Standard (non-OEM) silver Mikunis. I know Ed @ full spec. uses starts out with the 44mm silver Standard Mikunis.

I know Parker has a good price on them, and even better if you can get them on sale.


I just bought a brand new pair from Parker because the extra ~$150 you save buying a good set of USED OEM 44mm Mikunis just is not worth the extra tuning headache.

Parker Price: $175 x 2 = $350

Powerbombs $1000, Full Specs $1200, Regular $350, Used OEM $200


I may have missed it, but I cannot recall one person with Standard Mikunis who complains of the headaches associasted with the OEMs.

I am not bashing the OEMs, I think Nick uses them and is happy. But for those who want to get the detailed dialing on their carbs should go with the Standard Mikunis.

 

[nikad58]

I am very happy with OEM 44's (4 sets of them) set up by LPW also..

 

[waxhead]

if you are wishing to sell your oem carbs
please send me an email

 

[SkiDaddy]

Lets look at the SuperBN46mm carbs a bit. In addition to the carbs you need a throttle linkage, throttle wheel, bottom mounting adapters, and top mounting adapters (to use the OEM FA). Maybe throttle return springs and carb cable mount?

Will all these swap right off a stock pair of OEM 38 or 44mm carbs? Does the intake manifold need to be opened up or massaged? What about gaskets?

Who sells the best priced kit to swap out directly for OEM 44s?

 

[nikad58]

Lets look at the SuperBN46mm carbs a bit. In addition to the carbs you need a throttle linkage, throttle wheel, bottom mounting adapters, and top mounting adapters (to use the OEM FA). Maybe throttle return springs and carb cable mount?

Will all these swap right off a stock pair of OEM 38 or 44mm carbs? Does the intake manifold need to be opened up or massaged? What about gaskets?

Who sells the best priced kit to swap out directly for OEM 44s?

You would need.. Linkage yes (to run duals), throttle wheel no, no adapters, same top bolt pattern so the same flame arresters (just open then up 1mm all the way around) manifold yes opened up, gaskets opened up or buy 46's, no throttle return springs and carb cable mount.. stock is fine...

 

[#ZERO]

Will all these swap right off a stock pair of OEM 38 or 44mm carbs?

Does the intake manifold need to be opened up or massaged?

Who sells the best priced kit to swap out directly for OEM 44s?

Pro-Tec makes a nice manifold adapter to bolt the 44's on the 38's intake manifold and it only cost fifteen bucks.

I prefer to use the 760 intake manifold because the crossover is easier to fill and it's spaced a little further apart so the intake runners are more direct and the ports are larger.

I think Parker Yamaha has the best price on the 44mm Mikuni Carbs.

 

[Gilligan]

I know where a one piece wetjet manifold and 46mm carb are at for sell. Not mine I would not sell.

 

[felix5oh]

More to come.



Well, it looks like the msd enhancer did make a diffrence. This thing ran fine all summer without the ewci. This thread got me in the right direction. Then in daytona the enhancer crapped out and Saki let me use a stock cdi he had layin around.
Lost the 1/4 throttle responce,(lost wave setup) now it hesitates if i stab it on a plane.
It had:
120L
105H
2.0
80g
I advanced the stator 3mm ,nothing changed.
I lowered the pilot twice and it got worse. I ran out of tuning time but next weekend(weather permitting) I'll be trying the 65g then again try lowering the pilot to see what happens. Pop-off adustment was what got it crisp at 1/4 throttle the last time i had this problem with
wax and chuck's recomendation. Might have to order more pilots maybee?(125-130)



BTW it's a 62T, carbon reeds,dry pipe,protec head and silver mikuni's.


Also, a month before daytona ,i modified the exhaust outlet to a front only and put a scupper in place of the old exhaust exit. The exhaust exit hole was reduced to 2 1/2 inches. Would that change things? I didn't notice any change in any throttle position but i only got one tankful of riding before the enhancer crapped out.





I dont want to go back to another msd enhancer. Wax? You got something custom?

 

[waxhead]

I may have something new coming out in a mth or two
But cant say for certain just yet

I would say that setup you have is close but your pop off is to high
Think about the pop off as the point at what the low speed jet starts working
You can lower the popoff and the low speed jet will come in earlier

I would be going for baout 15-18 psi pop off on that setup you have

 

[felix5oh]

Yeah, that's the first thing i'm gonna try, a 65g.
When it had the enhancer it was fine and the carbs were driblling but it was the only way i could get it snappy from 1/4 to 1/2 throttle. In waist high water i had it idling fine with one turn out low, one and a half turns out high on each carb. Jumps out of thewater,great hole shot, good top end but still has a 1/4 throttle cough.




In the summer i will get another ignition system and have to do this all over again.

 

[waxhead]

if its dribbling then you need to put in new n/s
i would go for 2.3 with 80-95 gram springs

 

[teton]

Yes...the stock oem 44's Yamaha 760 carbs have the three hole low speed circuit.

One is for the low speed adjustment and the other two are the bypass holes.

-I know im bringing this thread back, but i just bought a set of 0em 44's from gill, and they have a 4 hole low speed circuit. the plate number is 120.

dont know what that means

here's my setup.

-dual 44's oem
-stock 44 flame arrestor- all screens
-r&d intake...crossover filled
-v-force 1 reeds
-62t cases...ported
-61x cylinder 82.5mm bore
-cylinder squish .45" decked .008" exhaust ports ported (widened only to 56mm)
-pro-x pistons
-6m6 stator/flywheel
-b-pipe mod
-ada head 37cc domes running 185 compression (this dosen't seem right and it may be my compression guage--will probably switch to 35 or 33 cc domes

im putting in the order for jets this week so i was wondering what everyone recomended i try......

 

[Mark44]

Here is what I have on a ported limited 701 duel 44’s 62T cylinder stock flame arrestor and 180 on compression.

120 pilots
105 mains
2.3 N&S
80 gram springs
15 pop off pressure

One thing I noticed well Waxhead noticed is that I was unable to tune the motor properly
with reed stuffers so those went in the trash can.

Mark44

 

[Big Kahuna]

Here is what I have on a ported limited 701 duel 44’s 62T cylinder stock flame arrestor and 180 on compression.

120 pilots
105 mains
2.3 N&S
80 gram springs
15 pop off pressure

One thing I noticed well Waxhead noticed is that I was unable to tune the motor properly
with reed stuffers so those went in the trash can.

Mark44

ok, so you have a ported limited, uh, thats a misnomer, a limited spec has no engine porting......... come one man, you been eating too much burnt popcorn.

So who are you dueling with, is it at ten paces or 30 paces??

 

[teton]

Here is what I have on a ported limited 701 duel 44’s 62T cylinder stock flame arrestor and 180 on compression.

120 pilots
105 mains
2.3 N&S
80 gram springs
15 pop off pressure

One thing I noticed well Waxhead noticed is that I was unable to tune the motor properly
with reed stuffers so those went in the trash can.

Mark44

yeah no reed spacers/stuffers/crap

here are the specs i am going to try first
115h/120L/2.0/95

i really want to order a bunch of jets so i dont have to wait a week shipping each time i want to try something else

oh yeah and pipe is mod b-pipe port matched of course

anyone else have any ideas of what i should be buying. i suck at tuning, and from eveyone else on this post it sounds like its going to be a lot of trial and error.

 

[Big Kahuna]

been running stuffers for 3 years, no tuning issues.