The hub on this one is aluminum with 6mm prop bolts..The tapered part is pressed into the center and didn't move, the hub moved enough on the crank to shear the key...No problem there, it's not thick enough or hard enough to keep the hub from slipping if it's not tight enough...I will get some fine valve grinding compound and mate the hub perfectly to the shaft, heat it a little, put some 680 green Loctite on the taper, and use FORCE to tighten the nut...
The cases on 3Ws are held together using 6 bolts on the 200...The 2 on the front are 5mm, the other 4 are 6mm..One or more of the case bolts are close enough to the inside of the case to leak case pressure if no sealer is used on the threads...This one had only 1 close that way, and it showed a very slight leak under the head...Some Three Bond 1104 on the bolt and case joint will fix the leak...
The rear cylinder had gotten hot enough to almost stick the piston, some skirt material was deposited on the bore...A little swimming pool acid on that fixed it, a few turns in the bore with a silicon carbide ball hone smoothed it out nicely...Used a 3M fine deburr wheel on the piston, good as new....
All 3Ws have a mark on the hub and case corresponding to TDC...If you're having mysterious trouble with a 3W, put it on TDC and check out the marks...They run really bad if the hub slips on the taper