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Re: A slight case of wet sumping -Do I need to worry?

Ian Wright
['It does seem odd to me that the “pump ratio” on the in vs the out side of the pump changes with revs...']..

I'm not quite sure what you mean there Simon...The feed gears have a smaller pumping capacity relative to the return gears as the system is a 'dry sump' system...This ensures the crankcase is scavenged (dry) when the engine is running and is the reason on initial start up that a constant flow will soon turn into an intermittent one once any residual oil is cleared from the crank case....

The capacity of both sides of the pump increases or decreases in proportion to rising and/or falling engine revs but not independently of each other...Ian
"The feed gears have a smaller pumping capacity relative to the return gears as the system is a 'dry sump' system...This ensures the crankcase is scavenged (dry) when the engine is running and is the reason on initial start up that a constant flow will soon turn into an intermittent one once any residual oil is cleared from the crank case."

Yes, thats exactly what I meant Ian. Why would it wet sump at idle-revs and then dry sump at higher revs?
It did but it makes no sense!

Best regards,

Simon

Re: A slight case of wet sumping -Do I need to worry?

I think Allans theory is the best fit for that...Ian

email (option): ian@wright52.plus.com

Re: A slight case of wet sumping -Do I need to worry?

If you think the scavenge pump is the problem.

Idle the bike until it starts smoking out the exhaust. Shut the engine off and remove the drain plug and see how much oil actually comes out.

Do the same test with increased RPM's until it does not smoke and drain it again. The oil quantities should be identical.

Re: A slight case of wet sumping -Do I need to worry?

Hello Simon,

Did you ever resolve the problem?

Best wishes,

Allan

email (option): allanmatchless@yahoo.com

Re: A slight case of wet sumping -Do I need to worry?

this happened to me on a unit Triumph. had me stumped. after a rebore, new pistons and rings, new valves and guides it still kept wet sumping while I was riding. Eventually I pulled the oil pump and found a tiny piece of hard crap that was caught in the scavange side ball bearing. A five minute fix which took me several months and quite a lot of money.

email (option): cas.vanderwoude@gmail.com

Re: A slight case of wet sumping -Do I need to worry?

Allan Hunter
Hello Simon,

Did you ever resolve the problem?

Best wishes,

Allan
Aloha,

And thanks for asking, been busy doing other things so have not gotten round to look into it.

/s

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