March 2000 Tech Tip   
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 Thrustwasher TechTip
   By Cotten
A common point of damage on Indian flywheel assemblies is where the tiny .090" pins which restrain the mainshaft flywashers have failed for one reason or another. We hope that any cause for this, such as alignment, will come out in the wash of an over-haul. However, we are still faced with certain problems by nature of their design. 

To begin with, some of the flywheels intended for service have had numerous repairs already, and more holes so close to the taper may not be prudent, particularly if they are some wormy cast ones. And the recess counterbored to recieve the washer may have been damaged and deepened by wear. The mainshaft interferes with the drilling of new pin holes unless you remove it, or use a specially ordered jobber's length bit. And if you use an original washer, you will find that pins were often not exactly opposite of each other, hence many modern replacements are supplied un-notched and must be hand-fitted. 

And imagine your frustration if one of those little pins crystallized into 
shards and flew into your sump.  After all, the tiniest part is often the 

Since Milwaukee parts are close at hand, I compared the flywasher to tanged thrustwashers from common "star" hub assembles (OEM 43563-35) and found a match of inner and outer diameters. 

Since the function of the pins and tang were both to "dog" the washer, or prevent it from spinning, I merely filed away part of the counterbore web to accept the tang. 

The tanged washers are .060 thick, whereas the original Indian washers come in .057" and.062". Also available by H-D design are .002" shim washers (OEM 43560-35) which are not tanged but will accurately fit behind the thrustwasher against the flywheel, as well as an aftermarket .007" variety. 

If one ground out the inside diameter appropriately, this fix could be 
applied to crankpin thrustwashers as well. 

Hardness testing revealed that a modern aftermarket tanged washer (V-Twin Mfg. was treated to Rockwell 50 C, and a vintage pinion race tested on the thrust face registered Rockwell 60-62 C. 

I would suggest this salvage repair to anyone planning a performance motor that may deliver thrusts and stresses beyond the norm, such as strokers or powerplants destined for sidehack duty.  It would be wise, however, to balance the flywheel assembly with the washers installed. ....Cotten

Chief flywheels with HD "star" hub thrustwasher. The big wristpin bushings are for Kaiser pistons,  
but that's another story... 

And (for no other reason than 
to post a nice picture!) here's 
beautiful Chief powerplant, 
Cotten built earlier.