R65 '81 onwards Jet Sizes

[Julio A.]

Hi Guys, by any chance anybody knows what the original jet sized are for the 81' onwards R65's?

I'm only have been able to see though my internet searching skills, the specs for the 78'-80' R65 Jettings.
AFAIK, these specs run richer than the 81' onwards.

[Barry]

Here's a few to choose from:

Original riders handbook
64/32/307 & 8
145
2.64
needle 46-241 in position 4
45

Haynes UK jetting:
64/32/307 & 8
148
2.64
needle 46-241 in position 4
45

Haynes US jetting:
64/32/325 & 6
145
2.66
needle 46-241 in position 3
40

Not sure why the difference in main jet size between BMW handbook and Haynes  but it's very unlikely to be worth worrying about as main jet size changed again in 83 to 138 (UK)  135(US).

[georgesgiralt]

Well, it depends on the market (pollution status, etc) and the installation of the cover of air filter box with asymmetrical trumps.
IMHO, it was far easier for BMW to change jetting to comply with local regulations than to modify the engine further... Loosing a couple of horse power was not a problem....

[Bob_Roller]

My '81 R65  carb numbers 64/32/325-6 had 145 main jets .
I had an assortment of jet sizes, spare parts from the two other R65's I have .
I installed 138 main jets to see if I could get better fuel economy, no difference in fuel usage, or engine performance .
I don't think the main jet size comes into to play, until you're at high power settings .
I put an index mark on the right hand grip, and corresponding marks, idle, 1/4, 1/2, 3/4 and full throttle on the adjacent switch case .
 I'm usually at around half throttle in my normal riding after going through the gears .

[Julio A.]

Thanks for the info Guys.

I'm also curious about putting jets they used on the Mono R65's on earlier models. AFAIK, they put smaller jets on those models right?