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Discussion Starter #1 (Edited)
Crankshaft bearing lubrication design

All but one motorcycle has the crankshaft bearings lubricated by pumping oil through the crankcase through small holes onto the crankshaft main bearing. The connecting rod big end bearings get oil from small holes inside the crankshaft that lead from the main bearings.

This new design pumps oil directly into the end of the crankshaft. Less oil pressure is required to lubricate the crankshaft main and connecting rod bearings. One advantage is that less power is used to create the high pressure oil. The other advantage is better lubrication.

Which motorcycle uses this new design?

Andy
 

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Andy, I don't know about new designs but Harleys, at least K models in '52, were like that. The oil went in the end of the crank from the cam cover side and was distributed to the crank journal through drilled passages. I'm sure this isn't what you were after. They only used a max of about 12 PSI due to the all roller bearing design.
 

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Discussion Starter #4
Dad & Rcjohn,

I couldn't find any information on either of the two models that shows that oil is pumped in from the end of the crankshaft through a hole in the crankshaft that leads to the bearings of the crankshaft.
The benefit of pumping oil in the end of the crankshaft is that centrifugal force helps the oil come out to lubricate the bearing.

On the other hand the problem with a conventional design is that oil has to be pushed under high pressure towards the spinning crankshaft (at the main bearing) and centrifugal force is fighting the oil trying to be forced into the crankshaft holes (which end up lubricating the big end of the rod bearings).

Andy
 

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Discussion Starter #5
How's about a little hint...

This motorcycle is a v-twin and has two fuel injectors per cylinder.

Andy
 

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That's actually on obvious and easy way to introduce oil into any single throw crank. When you get into multiple crank throws, the practicality of drilling oil passages from the end of the crank to all journals becomes extremely difficult plus it fights the same inertia force you talked about. They all take advantage of the inertia when the oil is introduced at the mains and flows outwards to the crank journals.
 
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