Woodruff Key Sizes

[ramwing7]

Anybody know the woodruff key sizes on the magneto end of the M engine crankshaft?

There are two.  A large and a small.

Thanks.

[Ricks]

There is only 1 hey, which is .750 x .125. The other slot is for the magneto cam. Check the manuals here if you are unsure how this fits together. Here is a picture on an early crank, but it is the same.

[pd]

According to the manual ( https://simplexservi-cycle.com/index.php?topic=430.0) , the keys are 5/8" or 3/4" long .
I'm guessing that along with the Sportsman motor , some standard M motors also used 2 of the 5/8" keys .
My M motor uses a single 3/4" key with about 1/8" 'cutout' to fit the shallower portion of the key-way .

I have bought bigger keys and filed them down to a snug fit .

Pete .

[Ricks]

Pete, don’t confuse the man! The reason the Sportsman use 2 keys is because the motor drive pulley does not screw on to the Sportsman crank, but is keyed on. That is the 2nd key. The keyway on the end of the crank is the same on all the cranks, and it takes only 1 key.

[pd]

Pete, don’t confuse the man! The reason the Sportsman use 2 keys is because the motor drive pulley does not screw on to the Sportsman crank, but is keyed on. That is the 2nd key. The keyway on the end of the crank is the same on all the cranks, and it takes only 1 key.

No harm intended .
Thanks , Rick .
Learn something new , every day .

Pete .