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Mikuni carb re-build
Posted: Sun Sep 19, 2010 4:33 pm
by philrock
I'm re-building a Mikuni 34 mm gas carb to use on a Mc101.
What should the pop-off pressure be?
What should the fulcrum arm height be?
When I was cleaning the carb body, holding it upside down, a couple of small copper discs fell out. They are 1/8" diameter x 0.015 " thick. I can't figure out where they came from. Help!
Re: Mikuni carb re-build
Posted: Sun Sep 19, 2010 8:26 pm
by Rob Voska
For gas I would start at 10. If it's fat on bottom raise it.
Arm? Usually for gas even with the floor on the carb but I use Tilly's & no expert on Mikuni's.
Washers came from under the brass needle seat when you removed it.
I also adjust arm heigth & pop off by needle settings. I don't like to run less than 3/4 of a turn ever on anything except a Yamaha. I will change the above to get needles in a comfortable setting area. 3/4 - 1 on H & 1 1/4 - 2 on low.
Re: Mikuni carb re-build
Posted: Sun Sep 19, 2010 8:31 pm
by Tom Luttenbacher
The discs you are talking about came from under the fulcrum arm spring...its an E.C. Birt/Carbs/Dist set up. I would call E.C. Dist for the particulars. They did an Alky convertion for me on a 34 Mik and I found the same discs so I called and asked. Tom
Re: Mikuni carb re-build
Posted: Sun Sep 19, 2010 9:29 pm
by Rob Voska
Tom's right & I was wr wr wro wr wrong.

Was thinking of something else.
Re: Mikuni carb re-build
Posted: Sun Sep 19, 2010 11:01 pm
by louie figone
Tom and Rob are right, they are spacers to fine tune the pop off pressure. 9 to 10 lbs works on the Mikuni and the large Tillotson on gas.
Louie
Re: Mikuni carb re-build
Posted: Mon Sep 20, 2010 10:38 am
by philrock
Anyone know what the fulcrum arm height should be?
Re: Mikuni carb re-build
Posted: Mon Sep 20, 2010 10:42 pm
by louie figone
Flush with the body.
Louie
Re: Mikuni carb re-build
Posted: Tue Sep 21, 2010 9:02 am
by Tom Luttenbacher
www.eccarburetors.com/aka as EC Distributing/615-446-6807. Check out the site there are some great pics of karting and lots of other links. Tom L
Re: Mikuni carb re-build
Posted: Tue Sep 21, 2010 9:03 am
by Tom Luttenbacher
Dont include the "/aka" if you do an online search. TL
Re: Mikuni carb re-build
Posted: Tue Sep 21, 2010 2:10 pm
by philrock
Guys - thanks very much for your help!!