Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties carburettor for 1941 U

carburettor for 1941 U

Moderators: Curt!, Pa

Post Thu Jul 11, 2002 6:15 pm

Posts: 607
Location: Menomonie, Wisconsin, USA
Ron I have run M88's as is on U's with no problem. I would leave the venturi alone and just change the fixed jet to adjustable. Just remember to remove the jet and plug the hole when you do it.

BTW M88 is listed as a replacement for M51 in some charts. Jerry

Post Fri Jul 12, 2002 12:00 am

It's a bit small - if that's OK just run it. If you want some power back:
1. use an Indian (internally vented) 1-1/16" or 1-1/8" venturi, or
2. cut a notch in the leading edge of your M-51 venturi:
Image , or
3. try to modify your M-88 body to get correction air from outside (doesn't sound easy).

Click here to read about my Mikuni Book

[This message has been edited by panic (edited 12 July 2002).]

Post Wed Jul 17, 2002 1:01 am

I have a gut feeling that back in the day H-D was more concerned about mixture control, and that there were actually differences between, for example, an M-41 (45") and M-51 (80") than just the stamp. One possible is that the drilled external vent allowed air correction to be done based on model, but still keep the venturis interchangable.
Then the accountants got it - and they decided "one size fits all" saves money, and who cares? The OHV is selling well.

Post Wed Jul 17, 2002 3:39 am
Wasn't the M-41 for 74"? and the M-41L for Later VL? M-51's were also run on 45's 47-up WLD's

Post Wed Jul 17, 2002 1:27 pm

Posts: 3008
Location: Central Illinois, USA
Ziggy has new vented venturis in various sizes, although blowing out your M88 venturi in a lathe would be a snap.

(PS: I have an M65 body in my trade stash, if you are going military. I need bowls; lotsa bowls..)

Post Wed Jul 17, 2002 3:30 pm

Sorry, duh.

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