jets on linkert

[61FLHPan]

I have a M74 i was reading that the main jet should be a 17 I have a 19 inthere now but it seame like i am geting to much gas i am going to put a new float on it when it come in the mail I was reading that M74 are 17 and M74b are 19 would that make a different in performante the carb is on 1961flh any help thank you

[Cotten]

61FLHPan!

There is very little difference between the M74 and the M74B except the jet.

The #19 might allow the HS needle to be a bit more sensitive, as it would probably find adjustment at fewer turns open.

But overall performance should be the same with either jet, as the needle tunes the difference, by adding more fuel than the jet alone.

...Cotten

[txdennis]

Was about to post a thread today about the Linkert woes I've had today, but only after I pressure tested the system, which I still haven't. Any who, '61FLH motor, Generator Shovel Auto Advance Timer (points @ 0.020"), Champion RJ14YC @ 0.025" in the rear and RJ12YC up front, true Viton O-Rings & Linkert M74B with all brass needle/seat, Cotten Float and #19 jet.

Starts up 1st or 2nd kick hot/cold but front plug is covered in black soot and rear plug is wet. Also, wouldn't idle. I was about to pull the carb, pressure test and check to see if someone had drilled the jet out. That's when I decided to try running the motor with the low speed needle completely in. To my surprise, it never stalled out. Then I remembered that I installed a new low speed needle from VTwin as my original one was pitted. Long story long, the VTwin needle was about 1/4" too short (3 3/32"). I dug out a pretty rough used one (3 5/16") & she popped rt over & idles a lot better. Now I just gotta dial it and the mousetrap in. Hope that helps..

[Cotten]

TXDennis!

It sounds like you were sold a 1" Model M lowspeed needle, instead of a 1 1/4" and 1 1/2" needle.

You could always take the used one and spin it in a drill press to dress the point with a stone.

After a successful test for vacuum leaks, I would suggest going back to using the same plugs in both cylinders, and non-resistors as well.

....Cotten
(PS: The jury is still out on the brass floatvalve needles. The "English brass" alloy corrodes easily, as shown on the earlier productions with doomed rubber tips from the same source.)

VITON2.jpg

[partshunt]

My M74B had a #19 jet in it and is correct as per parts listings. However, it run too rich even with the hi speed needle closed off. I changed the jet to #18 and now the hi speed needle is able to supplement the mixture by running 1 turn out. With the #19 jet, I could not achieve hesitation even with the hi spd. needle in the fully closed position. Possibly may be due to the increased vacume and velocity using the larger Shovel intake valves. Much better acceleration and power now,.....Joe

[61FLHPan]

I am thinking about doing that to i put one of cotton float in the bike run great but when i get on the gas it seame like i am puting to much gas at one time when it kick in to high speed runs good I am thinking about changing the jet to a 17 or a18 Or maybe just leave it alone and ride it Thank You

[partshunt]

61FLHpan: Are you now running with the hi Speed needle fully closed? That would indicate too much fuel. Either too much vacume from a restricted air cleaner (and Some Are). Or possibly just jet down so that you can get hesitation with the Hi Spd needle near closed or closed. `The HS needle sould add mixture over the main jet....My needle is out about one turn now with #18 jet, mileage improved.......Joe