81 250R to a 34mm

[mattsoch]

I want to put a larger on my 81R. I have easy access to snowmobile carbs. i did a bit of searching on here and see that most people are using Keihin Carburetors. i was thinking about using a mikuni because thats what comes on most snowmobiles. I am not sure what type on mikunis they are.Or am i best to buy a PJ Keihin?
i have to buy a pipe so i though i might get the carb too.

[1986atc350x]

hey try to stick with keihn pe34 roundslide or pj34 flatslide,i have an 84 and I just
put a pj34 on mine,its basically bolt on,you have to use some finess to get it to fit
it the stock intake and airbox boots but it can be done.once they fit you will need to
acquire larger clamps for them the stock ones don't fit after.also if you run the pj34
the flat slide one the original throttle cable doesn't work,so you have to run a 86 atc250r
cable.im told the pe34 the 85250r carb fits with the stock cable.the problem with mikunis
is that the fuel inlet in on the opposite side and not sure how the jetting would fair with
your setup,just best off to stick with what has been done before and works.not to say
you couldn't make the mikuni work,anyway you decision in the end. atcs!

[1986atc350x]

hey sorry I think you may have a smaller carb then mine stock.its
possible you may need to purchase a new reed boot to get the 34mm
to fit.my 84 is a 30mm keihn I think your may be a 28mm,not completely
sure though check the numbers on the side of your carb.you should find
a pe followed by 2 numbers indicating the size (mm) of your carb.anyway hope this helps

[manbearpig]

ive never had very good luck with mikuni's . just seem very finicky and prone to air slipping past the slide and also have float issues. ive given them a fair shot, but have always had good predictable performance with the larger Keihins. i have a 30mm on my 82R and a 34mm on my nicholson 250R and will be upgrading the 30 to the 34 once i find another 34 roundslide

[mattsoch]

The only reason i was going with Mikun'is that they are free vs $200 for Keihin

[1986atc350x]

hey I just picked up a brand new in the box off ebay 150 free shipping!
or they have good used ones anywhere from 78-120 some with cable and
throttle lever.