Author Topic: oil level in sight glass  (Read 1772 times)

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suitcasejefferson

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on: March 23, 2014, 07:11:22 pm
I never noticed this before, but is it normal for the oil level to show full in the sight glass when the engine is running on the centerstand? Just about every bike I've ever had the oil level would drop all the way to the bottom when the engine was started. I just got back from a 20+ mile ride after changing the oil and filter, so I'm sure if it didn't have oil pressure it wouldn't have made it that far. It does seem a bit odd though, at least compared to a Japanese bike.
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Arizoni

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Reply #1 on: March 24, 2014, 12:09:30 am
Yes, the sight window can be full while the engine is running with the motorcycle on the centerstand.

The oil system delivers the oil to three locations after the oil passes thru the filter.
A lot of it goes to the hole in the center of the crankshaft which lubes the bearings and piston.  That oil is then thrown off into the crankcase where the flywheels on the crankshaft throw it over the wall onto the transmission gears.

Some of the oil goes from the filter to the hydraulic valve lifters.

The rest of the oil goes up the rear of the cylinder thru a passage to lubricate the rocker arms and valves.  This oil drains back down thru the pushrod tunnel into the right sidecase to lubricate the cam gears, the roller cam followers, the oil pump gear and to cool the alternator.

Although the bottom of the drain hole from the right sidecover area is lower than the sight guage the oil level will tend to build up in this area so it tends to fill the window until the engine is shut off.  Then, the excess oil will drain back into the oil tank.
« Last Edit: March 24, 2014, 12:12:02 am by Arizoni »
Jim
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suitcasejefferson

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Reply #2 on: March 24, 2014, 01:07:19 am
Thanks for an excellent explanation.
"I am a motorcyclist, NOT a biker"
"Buy the ticket, take the ride" Hunter S. Thompson