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modern sealing and loss reduction

2K views 14 replies 4 participants last post by  HackAsaw 
quote:Originally posted by HackAsaw

could be the subject title appropriate for a bike build

what's been done to the pushrod tube bore and why?



Uhhh, the ore has been radiused to allow the pushrod o-ring to compress rather than be sliced during assembly? Bonneville head, correct? Set screw holes drilled and tapped for exhaust spigots?
Do I win any old bike parts?

-James
 
quote:Originally posted by HackAsaw

could be the subject title appropriate for a bike build

what's been done to the pushrod tube bore and why?



Uhhh, the ore has been radiused to allow the pushrod o-ring to compress rather than be sliced during assembly? Bonneville head, correct? Set screw holes drilled and tapped for exhaust spigots?
Do I win any old bike parts?

-James
 
quote:Originally posted by HackAsaw

ummm 66 bonneville head....... that is not the right answer as to what has been done to them or why. the lead in chamfer was done by the
factory
Damn, a loser again! Maybe next time.
I agree oil sealing could be improved on 650 twins, but I understand it also has something to do with poor crankcase ventilation and both pistons moving together rather than 180 degrees apart.
As for un-shrouding the valves, it looks like you basically smoothed out the chamber around the circumference of the valve, no? Any before pics? I wonder how yours compared to my later '71-72 heads in this area before you started work.

-James

-James
 
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