Tuesday, December 16, 2014

V2 crankshaft and tailshaft bearing placement confusion resolved

Q&A e-mails with Ernie (Q) from South Florida and me (A):


Q: Sheet #22, Crankshaft – The bearing diameter portions of the shaft as noted on the drawing are .500” & .437”.  However, the bearing used on the shaft have inside diameters of .500 which is OK, but the other is (supplied by you) 12mm. However, 12mm = .472”, therefore, the .437” shown on the drawing must be wrong; it should be .472” or 12mm.  The bearing supplied is 12mm ID x 21mm OD x 5mm thick.

A: The crankshaft in the V2 is not like a traditional one-piece crankshaft where you have two ends with the connecting rod throw in the middle.   Basically, this shaft has just ONE end.  On the other side of the crankdisk is the tailshaft.  Both crankshaft bearings are mounted to the crankshaft, but on the SAME side of the crankdisk.  See the crankshaft housing on page 13.  Both crankshaft bearings fit in the housing, and the crankshaft slides into BOTH bearings.

The other side of the crankdisk is the tailshaft (Pg 10), supported by two bearings, with the inner tailshaft receiving the 12mm x 21mm x 5mm bearing, and the outer tailshaft will receive the .250 ID x .500 OD x .187 bearing.

Q: Look on page #18, the figure in the upper left. Note the tailshaft (it is .375” dia.) The ball bearing is 12mm ID x 21mm OD x 5mm thick.  12mm is .472”.  How does a .472 dia. bearing fit a .375 dia. shaft?

A: Both crankshaft bearings are .500 ID, and they BOTH slide onto the .500 diameter section of the crankshaft as illustrated at the top of page 22.

The 12mm ID x 21mm OD by 5mm bearing is NOT mounted on the tailshaft, but rather, it is mounted on the Tailshaft Crankdisk, bottom right on Pg 22 (thus the .472), and the tailshaft is inserted into the crankdisk (thus the .375 ream).

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