74" or 61" Panhead flywheels

[Aboatguy]

I believe these are 61" flywheels. I read that you can tell from the retaining screw location. Is that true, if so are these EL or FL wheels?



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Thanks so much

Mike

[Rubone]

If you are not sure, measure center to center on the shaft to crankpin hole. A close approximation is good enough. A 61 is 1-3/4 inches, half of 3-1/2. A 74 is close to 2 inches, half of 3-31/32. The close to 1/4 inch difference is very obvious.

[Jerry Wieland]

Mike Yes those are the late EL flywheels. 1941 to 1952.

I believe these are 61" flywheels. I read that you can tell from the retaining screw location. Is that true, if so are these EL or FL wheels?



Jerry



Thanks so much

Mike

[Aboatguy]

Thanks again!

[Jerry Wieland]

Mike Yes the way to instantly tell if the flywheel is a 61" or a 74 is by the location of the retaining screw. If you can just imagine that the inner radius of the flywheel would continue full circle instead of being relieved for crankpin nut clearance. The retaining screw on EL flywheels is inside of that radius while the screw on FL flywheels is outside of that radius. The actual crankpin hole is smaller on a EL wheel but when you are looking at a single flywheel that feature can be hard to pick out.

Jerry