Carburetor and Fuel System
Title: Linkert
M74-B settings
Post by Cotten on Jul 12, 2007, 12:17pm
We assume you mean an M74B?
About 3/4ths of a turn on the highspeed, and at least four on the low.
Expect the lowspeed to be trimmed down after starting, and the highspeed to do little or nothing.
....Cotten
Post by pandit on Jul 12, 2007, 7:22pm
See service manual 1959-1969:
A carburator may be adjusted as follow:Turn both low and high-speed needles all the way in (clockwise). Back out the low speed needle five turns. Back out the high-speed needle two turns. With needles in these positions, the engine will start but the mixture will be too rich. Advance spark all the way or nearly all the way, whichever is best. Warm engine to full operating temperature and correct adjustment of both needles.
Adjust low speed first, with engine at operating temperature and ideling. Turn needle in, one notch at a time, until mixture becomes so lean that engine misses and acts starved. Back out the needle five to ten notches, or until engine hits regularly with spark advanced and throttle closed, or as nearly closed as it can be set and still have engine run at ideling speed.
Pandit, Switzerland
Post by Cotten on Jul 17, 2007, 3:23pm
It should be kept in mind that the settings from the Manual are hold-overs from the earliest models using Linkerts.
Linkert models are many, so specifying needle settings for each variation over the many model years would be needless confusion when trial-and-error prevails anyway.
Although the Manual spec works for a one-size-fitz-all rule of thumb, I can assure you all from extended experience that your Pan will start out much more 'comfortably' at the lower settings I suggested.
(Assuming all hardware is in order!)
Very few early models (nearly all military) had fixed jets.
Our Pans have big ones.
(With the exception of '48, and early '49, apparently.)
Fixed jets allow the highspeed needle to be trimmed down to a range of reasonable sensitivity, as the bulk of fuel flows into the nozzle well unobstructed. In service, the needle's primary use is for trimming fuel down further for increases in altitude.
....Cotten
Post by DuoDave on Jul 18, 2007, 1:27am
You will find your pan very hard to start with the low speed needle dialled out five turns. Every bike is different of course, but I found having the low speed needle about two and a half turns out is right for my pan. Try Cotten's settings or maybe just three turns out on the low speed needle as a starting point.
Post by 62trvler on Jul 24, 2007, 11:33am
Thanks to all for the valuable info. I appreciate your input.
