T350 oil pump output

kmil · Post by **kmil** » Sun Jul 05, 2009 7:42 pm

I have been purging the oil lines on my T350 and it seems that one side of the oil pump is pushing out more oil that the other side. With the clutch side cover off you can insert the oil pump drive shaft and with a short piece of rubber hose as a coupling drive the oil pump with a drill. While doing this I noticed that one side seems to be putting out more oil. Can one output go bad without affecting the other? I don't want to starve one side of the motor after putting all this money in it. New oil pumps seem to be quite expensive. Has anyone else noticed this?

Barry S. · Post by **Barry S.** » Mon Jul 06, 2009 4:34 am

I'm not sure about how they work but the crank bearings probably don't need as much oil as the lines that feeds into the intake, just a thought.

kmil · Post by **kmil** » Thu Jul 09, 2009 4:45 pm

Thanks for the answer Barry S. It looks like no one knows the answer. I guess I will disassemble an old pump and try to figure it out.

Zunspec4 · Post by **Zunspec4** » Sat Jul 11, 2009 4:59 am

Hi kmil,

I saw that you posted this question on the Classic Bike forum but this forum probably has more expertise to judge my notion of the problem

.

On the T500 pump I have always assumed the actual pump mechanism fed into some sort of a T junction to provide two outlets which in turn have a Y junction to feed bearing & barrel. In theory the pressure should be the same throughout the system. However this pressure has to overcome the sris (sp?) valve thingy (technical term

(one way valve) where the coupling banjo mounts on the engine. If the pressure needed to lift the sris valves is not equal one side might flow more oil than the other resulting a "Smokey" side to the engine if you get my drift. I am assuming the T350 pump feed to the bearings is much the same as the T500

I'm not saying the above is anything than complete drivel but it's the only thing I can think of. The folks on here can probably judge the merits of the theory.

Cheers Zunspec (he of the shiny T500

elbert · Post by **elbert** » Sat Jul 11, 2009 5:40 am

I belive the check valves on all four oil lines should be the same so if you measure the oil flow on each of them they should be fairly close.
When the oil pump on the 350 is spun with 1000 rpm it should deliver 145cc/hr of oil when the lever on the oil pump is fully open (between 60 and 72 degrees from "closed" position).

What I would have done is to check the check valves by blowing and sucking air through them to se if they act as one way valves, if you don't like getting oil in your mouth you could put a nut on the banjo bolt and use a syringe. If the check valve doesn't work a good cleaning with alcohool could help but some times it is physicaly broken.

I wouldn't wory to much if the difference between oil delivery isn't huge.

kmil · Post by **kmil** » Tue Jul 14, 2009 9:28 pm

Guys,
I changed out the right oil line with one of my older lines and now I have equal flow. I tried to disassemble the line that was giving trouble but it looks like it is not made to be taken apart. I flushed it with alcohol but it still didn't help. Must have a clog in one of the fittings. Thanks to all who answered. I feel much better about closing the engine up now.

rngdng · Post by **rngdng** » Wed Jul 15, 2009 5:55 pm

The check valves can be taken apart, but a propane torch may be required. They are a very tight fit, and don't come apart easily. IF you get it apart, be careful not to stretch the spring. Clean all parts well, and the check valve should work again.

Lane