Author Topic: '76 750F, Difference between pin, special knock and pin, dowel?  (Read 1163 times)

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Offline eshumaker

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So,  I sent the cylinder out to get honed, and couldn't get some of the dowel pins out. No big deal, but now that I go to MotoGrid to scan for part numbers, the cylinder head microfiche makes reference to PIN, DOWEL (12X18) (Honda Code 0253773) requires 4, and PIN, SPECIAL KNOCK (12MM) (Honda Code 0390740) requires 8.

So, as I don't have either, what's the difference?  ??? I only remember 2 12mm dowels on the cylinder - crankcase, and another 2 on the crankcase - head. I have already got the 8mm dowels I will need.

Any help appreciated!

E
1976 CB750 (basket case in progress)
1979 GL1000 Goldwing (runner)
1983 CB750 Nighthawk (basket case)
2004 Yamaha R6 (commuter)

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: '76 750F, Difference between pin, special knock and pin, dowel?
« Reply #1 on: August 16, 2010, 11:34:51 PM »
The special knock as Motogrid has pictured (#3) I believe are for the oil returns as you will notice the gaskets, cylinder stud bolt (#2) that encircle them while the pin, dowels (#8) are for alignment only between the cylinders and head.  

Not sure if/when the earlier cylinders had all the pins. Does your head have 392 cast onto the top fin intake side beside #3? It should. If not then you may have an earlier head grafted onto your engine or an earlier top end. What is your engine serial number?
« Last Edit: August 16, 2010, 11:39:00 PM by Jerry Rxman Griffin »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)