Bad news on my K321 crank
 

It will take at least .030 to clean it up. I may have stumbled upon another option today though. I brought home a retired K301 from an air compressor. After stripping it down, I have found a mint crank although the PTO end is the wrong size. Not a problem as I do not plan on using a PTO on this tractor. I also noticed the counter weights do not have flats milled in them, look just like the K321 crank weights. I then took the pistons and rods to the scale to compare the 301/321 weights. The 321 piston with rod and rings weighed a whopping 1/2 ounce more than the 301 assy. A whole 14 grams. I could probably lose that much in getting rid of the casting flash and polishing the beams of the new rod and piston.

I know the purists here will not like my plan but would you run this crank in a K321?? This tractor is gonna be for plowing and pulling a small trailer. The mower deck is staying on my 1200.

I also scored a good stator, a rectifier (haven't tested it yet), head, and cam shaft.

The cam has me wondering. This K301 had a magneto. No points. This cam was never machined with a cam lobe though the extra meat is there to do so. If I send this cam out to be modified into a "cheater" profile, can they grind the lobe for the points operating shaft?? Who can do this??

If it has a mag and no points, it's probably an M12 and not a K301. I would stick with the correct K321 crank. They are different for a reason.

It had a K301 cast into the block on the PTO side.

That doesn't necessarily mean it's a K301...I think the Magnum single blocks were very similar to the K-series without machining for points. Post a pic of the area where the points would have been on the K-series and we can tell for sure.

The K-series mag ignition still would have used the points. The Magnum does not have points.

I have been searching through Kohler's parts lookup. I think Matt is correct in that what I was given today is indeed an M12.
Now here is something weird I have found on Kohler's site, the crank used in the M12 471536 is the same crank used the K321 60312. Back to more research. I may just use this M12 crank, the price is right and if it doesn't work out, I am just out some time.

Machined surface is there but no hole for points rod nor holes for screws to hold points or cover. Maybe Kohler used up K301 inventory on their M12 production?? Or just kept using the 301 block less a couple of machining steps?

Well I learned some things today at work. If you take the rod studs and nuts out of an M12 rod and install them into an early K321 rod, then the K321 rod/piston combination now weighs LESS (by a few grams) than the M12 Maule piston and rod combo. Kinda throws the lighter/heavier counter weight thing out the window. I will be using the M12 crank in my K321 with a new, early style, rod/piston combo, modded with rod studs and nuts. If I ever desire to reinstall my PTO clutch, I will pull the crank back out and chuck it up in my lathe and turn the PTO end to the correct dimension. I will update how the beast runs when I get it back together.

Gonna take your advice. Only gotta remove .064 from the shaft and shorten it a touch over 3/4". I am gonna destroy the M12 flywheel to use it as a fixture to chuck up the crank. Should not be too hard to do. :bigthink: