Choke usage with th Linkert M74B

[steve_wood]

Just got the 56 FLH back together today. Amazingly, it fired on the first live kick!

But I noticed that it would only run with the choke on full....

I only ran it for a few minutes - enough to get the engine hot and enough to fill a 20 ounce container of oil from the oil pump return, so I don't really know what would happen if I ran it more.

Anybody have a similar experience? Do some engines just need lots of choke until they get really warm?

Here's some of the pertinent data:

- The Linkert high speed and low speed jets were set up per the Clymer manual

- The intake manifold was tested and it had no leaks

- I'm using an K&N air filter

Any thoughts?

steve

[FlatHeadSix]

Steve,

Most Linkerts rarely require ANY choke at all except for the primer kicks. Usual procedure involves a couple of primer kicks with the choke fully closed and then open it all the way for the starting kick. My experience has been that only extremely cold conditions require choke when warming up the engine, and then it is only one click closed. "Extreme" cold here in Arkansas is in the 30 degree area.

First guess would be a manifold leak somewhere, either between the carb and the manifold, or somewhere else in the intake plumbing. Check everything; the pan cover screws over the intake ports, and the intake nipples where they seal to the heads. If there are rivets in the nipples, check them too.

If you are sure the intake is not leaking then the problem has to be in the Linkert itself, something is blocking the idle circuit. At idle, the fuel exits the idle circuit through the tiny holes in the throttle body at the point where the throttle plate closes against the bore. Another problem might be float level, make sure that the float is not hanging up somewhere in the bowl and that it has sufficient travel to drop and fill the bowl to the proper level.

let us know what you find out. You have a beautiful bike, it should run as good as it looks!

mike

[FlatHeadSix]

Steve,
Another possible cause is valve adjustment. If you are not getting enough lift and duration it will limit how much fuel is pulled into the cylinder during the intake stroke. Spongy hydraulic lifters could be the problem and they may be acting that way simply because you have not run the engine long enough to get everything pumped up. Check the valve adjustment after a couple of complete heating & cooling cycles and see what happens.

just something else to look at,

mike

[VintageTwin]

I'd check starved fuel origins. Paint chips in fuel line, strainer, etc. Pull the float bowl. Check float action.
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wait a minute.........check the points setting first. 0.022" for 1936-1960. Okay? - then what color is the spark, blue or yellowish? Yellow points to a bad condenser first, and then coil checked last after condenser replacement.
Eluded to on pg. 21, Vol. 1, under Troubleshooting.
In summary, a motor that gets starved for spark (almost closed points) will demand a richer fuel mixture to continue running.
Check the points gap just for (the low effort factor) curiosity. If the points gap was closer than 0.022", I'd sure like to know, as it relates to a question awander posted, concerning the "running rich to survive" statement printed on pg. 21, and an affirmative response from you, would push the theory closer to fact.