Dual 44 Mikuni observations

crammit442

crammit442

makin' legs
Location
here
SuperJETT said:
You haven't followed this thread have you?

Perfectly clean, oem 44's run quite a bit different.
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:rolleyes: I've followed this thread with some amusement for these long months. I find it interesting that with good compression, porting, prop, etc that it takes months to tune a set of OEM 44's. They should be super forgiving and easy to tune. The reason I said the popoff sounds VERY low is that on decent carbs you should not need to go that low. According to the common wisdom(group K-mart, etc..) OEM's should be much easier to tune than aftermarket carbs. Yamaha motors are well known shakers and low pop can cause muddy bottom end. You just said they were ok, but you thought they could run better, didn't you? Well, maybe try higher pop!

Charles
 
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SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
crammit442 said:
:rolleyes: I've followed this thread with some amusement for these long months. I find it interesting that with good compression, porting, prop, etc that it takes months to tune a set of OEM 44's. They should be super forgiving and easy to tune. The reason I said the popoff sounds VERY low is that on decent carbs you should not need to go that low. According to the common wisdom(group K-mart, etc..) OEM's should be much easier to tune than aftermarket carbs. Yamaha motors are well known shakers and low pop can cause muddy bottom end. You just said they were ok, but you thought they could run better, didn't you? Well, maybe try higher pop!

Charles
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I've worked my way down the popoff scale from 32psi. So far, this has been the best pulling/cleanest.

My question is about the spacer plate really, my jetting is pretty good.

As far as taking months, I prefer to ride than tune, and with 3 kids in the family, my ride time is precious so I normally make one change then go ride. If it needs something other than a screw adjustment, I wait until the next ride.
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
SuperJETT said:
I've worked my way down the popoff scale from 32psi. So far, this has been the best pulling/cleanest.

My question is about the spacer plate really, my jetting is pretty good.

As far as taking months, I prefer to ride than tune, and with 3 kids in the family, my ride time is precious so I normally make one change then go ride. If it needs something other than a screw adjustment, I wait until the next ride.
Click to expand...

I have made a conscious effort this season to get my carbs tuned right - it's free power.
I have tried popoffs from 15psi to 32 psi, and have found the cleanest hit with 32psi. But again, that's just my motor.
 
SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
Matt_E said:
I have made a conscious effort this season to get my carbs tuned right - it's free power.
I have tried popoffs from 15psi to 32 psi, and have found the cleanest hit with 32psi. But again, that's just my motor.
Click to expand...

The jetting I have for regular 44's for my setup would be 120L/130H with 30psi popoff.
 
sjetrider

sjetrider

615 Freeriders are addicted to T1 madness.
Location
in the 615 (Nashville)
JFYI, I have the following set up in my sons boat.
94sj / 62Tcase / Riva mnfld w/ spacer / Boyesen pro series reads w/ stuffers/ twin 44 mikuni's / 61X ported cylender, modded stock CDI., ADA head w/ 35cc domes making 170 comp.. / B-ppipe w/ blaster mod chamber / 13/16 solas concord cut back prop w. WW cone stock nosal.

Carb jetting is 120p / 110m 95 grahm spring and 2.0 N/S 18 pop off.
seems to hit decent, but always looking for more.

Interesting that Wax says remove stuffer, gonna try that next time I remove mnfld.
 
Mark44

Mark44

Katie's Boss
Location
100% one place
sjetrider said:
JFYI, I have the following set up in my sons boat.
94sj / 62Tcase / Riva mnfld w/ spacer / Boyesen pro series reads w/ stuffers/ twin 44 mikuni's / 61X ported cylender, modded stock CDI., ADA head w/ 35cc domes making 170 comp.. / B-ppipe w/ blaster mod chamber / 13/16 solas concord cut back prop w. WW cone stock nosal.

Carb jetting is 120p / 110m 95 grahm spring and 2.0 N/S 18 pop off.
seems to hit decent, but always looking for more.

Interesting that Wax says remove stuffer, gonna try that next time I remove mnfld.
Click to expand...

Stuffers out was night and day on my 62T cylinder Magoo port:Banane01:
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
sjetrider said:
JFYI, I have the following set up in my sons boat.
94sj / 62Tcase / Riva mnfld w/ spacer / Boyesen pro series reads w/ stuffers/ twin 44 mikuni's / 61X ported cylender, modded stock CDI., ADA head w/ 35cc domes making 170 comp.. / B-ppipe w/ blaster mod chamber / 13/16 solas concord cut back prop w. WW cone stock nosal.

Carb jetting is 120p / 110m 95 grahm spring and 2.0 N/S 18 pop off.
seems to hit decent, but always looking for more.

Interesting that Wax says remove stuffer, gonna try that next time I remove mnfld.
Click to expand...


That needle & seat and spring will give you 25 psi, not 18.
 
W

waxhead

wannabe backflipper
Location
gold coast
i am sure your ski feels great bk
remove the stuffers and see what you think
they are limiting your airflow and giving you what you could get out of your carbs
 
W

waxhead

wannabe backflipper
Location
gold coast
i think both is the ultimate
but when one restricts the other to such a point that it kill hp its not a good thing

They may work on 38s
i havent tried then and since they have less airflow they may not be as badly effected by them
 
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