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Old timers help me out 93 yz250

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Just some back ground knowledge I'm far from stupid when it comes to wrenching on bikes have accomplished several bottom ends and topends,forks etc,this year not to mention the past, I work on bikes on the side for extra income, I'm currently redoing a 1993 yz250 engine for a customer, I have noticed that the bike no longer has a factory mikuni carb, but it has been replaced with a Keihin of some sort it's stamped pj28jan12 or I2 cannot depict the diff really, bare with me,

I'm only 22 and this bike was introduced when I was still shitting in diapers, I have done some research and apparently this was common to swap carbs but all I came up with were pwk38 and an air striker carb mod, can someone fill me in on this and tell me what carb I'm mainly asking so I can get some baseline jetting specs for this bike without being completely blind typically I'd set one up stock and go from there but with this not being a factory carb I'm unsure, If anyone has input help me out thanks. Attached a few pics below

ImageUploadedByThumper Talk1406682284.000515.jpg

ImageUploadedByThumper Talk1406682370.541671.jpgImageUploadedByThumper Talk1406682401.171103.jpgImageUploadedByThumper Talk1406682431.570171.jpg

Edited by yzdude250f

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PJ was a popular carb before the PWK was made big.

 

They're not bad carbs, but if it's a '93 - it's safe to assume the stock carb wore out, and that PJ is probably wore out as well.

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Can you measure the inside diameter of the carb bore? That will tell us the size anyhow, and we can go from there.

carb bore measures 38mm ImageUploadedByThumper Talk1406756401.366337.jpg

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Could be a pwm38 too.

The mikuni stock jetting for that year was 350 main, 40 pilot. That what I run on my 94 yz250

The Keihin stock should be around 170 main, 40 pilot but don't quote me on that

jetting in this carb is a little fat at 55pj 175 main

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Sweet I have a few spare 42 and 45 pj, I'll set the airscrew at 2 turns and read the plug from there, be a few weeks still waiting on crank bearings and the cylinder to come back.

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