Author Topic: YZ125J Jetting  (Read 1355 times)

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Offline wmc83

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YZ125J Jetting
« on: September 22, 2009, 06:06:24 pm »
Hi I'm about to buy a new Mikuni VM34 for my yz125j but I cant find out what size air jet to use. The old carb didnt have a jet where the air jet was supposed to go (I think it was drilled to the correct size from factory ?). The bike is stock std and is ridden at sea level anyone have any ideas.

Offline Lozza

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Re: YZ125J Jetting
« Reply #1 on: September 22, 2009, 07:38:35 pm »
I'm assuming your taking about the air corrector on the front of the carb? Most VM's don't have a jet or a screw(like later Keihins, maybe early ones too ;D) on the air correction circuit. You could if you wish drill/tap the hole to accept an air corrector, IIRC the hole is 2.8-30mm so putting a jet in will richen the fuel curve considerably.
Jesus only loves two strokes

Offline wmc83

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Re: YZ125J Jetting
« Reply #2 on: September 22, 2009, 08:35:31 pm »
Yes my old vm34 doesn't have one but the new vm34-168 ive bought says it has a #2.0 air jet as std ive looked at an elevation of the carb and it does show some sort of jet in there and you can buy them(jets that is). I think I'll see what comes in the mail and go from there.

Offline Lozza

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Re: YZ125J Jetting
« Reply #3 on: September 22, 2009, 10:09:22 pm »
A pic would be nice
Jesus only loves two strokes

Offline wmc83

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Re: YZ125J Jetting
« Reply #4 on: September 23, 2009, 05:42:30 pm »
I've got a diagram of a vm you can see the air jet on the inlet side of the carb.



Plus some progress photos of what i'm up to.