T20 oil pump

doug rooney · Post by **doug rooney** » Fri Jun 05, 2009 10:23 am

The right side line is sucking air in. Have had it off several times and filled it with oil but when I start it, it starts pulling in air. Have tried the metal gaskets and thought maybe that was the problem so went back to the old plastic ones and even put gasket sealer on them, made sure it was tight to specs. I have had the bottom plate off and quite a bit of oil came out of there. Book is not very clear on the bleeding procedure but I'm quite sure the air should not be coming in the banjo???
Any thoughts?? Thanks

elbert · Post by **elbert** » Fri Jun 05, 2009 12:38 pm

There are a check valve in the banjo, if it doesn't work propperly air will come in through the banjo.
I also experienced that very thin synthetic two stroke oil results in air bubbles in the lines, but they disapeared when i switched over to thicker oil.

doug rooney · Post by **doug rooney** » Fri Jun 05, 2009 3:10 pm

Thanks Elbert. Don't think it's the check valves (near the cylinders) and don't think it could be the oil or else both lines would have air and only one does. Plenty of oil in the line at the check valves. The air has to be coming from the pump. The banjos on the pump are secure and think the air must be coming into the pump some other way????

Odin · Post by **Odin** » Fri Jun 05, 2009 6:26 pm

Did you replace the o-ring at the bottom of the pump? the one beneath the plate. there is also an o-ring on the cable arm (you realy have to dismantle the pump to replace it.) as well there are the two bolts, the one on the top (it has an o-ring and the one on the face of the pump, plus the plate on the face of the pump is a plate with two screws, I sealed all of them with three bond to be safe.

doug rooney · Post by **doug rooney** » Fri Jun 05, 2009 7:06 pm

Ahhh, ok thanks Odin. Didn't do any of that but have about 300 assorted o rings with which to work. Gotta be something like that. Appreciate it boys.

doug rooney · Post by **doug rooney** » Fri Jul 03, 2009 7:01 am

doug rooney wrote:Thanks Elbert. Don't think it's the check valves (near the cylinders) and don't think it could be the oil or else both lines would have air and only one does. Plenty of oil in the line at the check valves. The air has to be coming from the pump. The banjos on the pump are secure and think the air must be coming into the pump some other way????

Quoting myself here. Having second thoughts about the check valves. Have tried 2 different pumps now and still sucking air near the right discharge line at the pump. Oil can be seen in the line near the check valve. Is it possible to have a bad check valve but have the air bubbles appear at the pump somehow working it's way through the crankcase?? The air bubbles get to as much as 1.5" or so and do not move steadily along the line when running. They stall for long periods at the pump.
Thanks

Suzukidave · Post by **Suzukidave** » Fri Jul 03, 2009 4:02 pm

Doug , is it possible the vent in the cap on the oil injection tank is blocked or not venting ?

doug rooney · Post by **doug rooney** » Fri Jul 03, 2009 5:58 pm

Don't think so Dave. When I loosen the intake bolt on the pump, oil flows out like crazy.
Today, I switched the check valves to see if the problem would follow the suspected bad valve over to the other side. I have no idea what has happened when I drove it around for quite awhile, but all I see at the pump now is solid oil and no air. I guess sometimes we get lucky with a tweak here or there but it seems ok so I'm happy!
Thanks, Doug