Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 350 Talk => Topic started by: davis on April 03, 2018, 02:38:12 PM

Title: Bench Testing 350 Oil Pump
Post by: davis on April 03, 2018, 02:38:12 PM
I have set up a bench test for the oil pump to verify pumping operation. Regardless of my best efforts I can not get two pumps to pump oil, so I wonder if anyone can offer a suggestion. The test was set up with an oil tank elevated about the same height as in the bike, 5-20 oil filling it and run down the inlet hose to a pump mounted on a side case fixed in a vise. The outlets empty into a open container. The shaft has the gear removed and is rotated by a 1500 rpm cordless drill (about 1200 rpm eqivalent engine speed) counter-clockwise. Results: NO OUTLET OIL FLOW at full pump control stroke. Took pumps apart for assembly inspection and they look good (timing was correct).

So, I've gone as far as I can, any ideas? Personally I need to see the pumps working before running the bike or I will remove the system and run just on mixture.

Thanks for any help.
Title: Re: Bench Testing 350 Oil Pump
Post by: OldSwartout on April 03, 2018, 03:44:09 PM
I'm not sure of the timing, but if the internal port to the crankcase isn't fully closed prior to the pump beginning it's retraction, maybe the oil is being drawn back into the pump, just like trying to bleed hydraulic brakes without closing the bleed screw at the right time.  It may need the check valves installed at the ends of the hoses to work.
Title: Re: Bench Testing 350 Oil Pump
Post by: BRT-GTR on April 03, 2018, 05:20:12 PM
            Spent a couple of days playing with oil pumps, last year, when I was having problems.  I agree with your direction of rotation.
        Also agree with Karl, with open outlets,  the pump is more likely to be sucking air back past the distributor valve in preference to pulling oil from the inlet port and relies on the check valves playing their part. Apart from that can only suggest warming the oil to improve its flow prior to the pump priming itself.

       If you mark the positions of the distributor ports on the gear and the position of the slot on the pump main rotor, you find the slot has already passed the inlet port by the time it retracts (at low flow).  How does it pump ? Couldn't figure that one out. There's more to these pumps than the manual indicates.  ;D                                          Brian.

Title: Re: Bench Testing 350 Oil Pump
Post by: coxy on April 06, 2018, 03:52:52 PM
there should be some posts from graham weeks somewhere on the site and if I can find some old emails ill try to post them
what I usually do is test it on the bike with clear oil lines and run premix in the tank
one of my pumps ,pumps oil out of the right outlet fine but dribbles out of the left this caused a seizure ,
Title: Re: Bench Testing 350 Oil Pump
Post by: davis on April 06, 2018, 06:12:43 PM
Lack of lubrication is my concern - seizures not welcomed! The bike appears to be running fine with the pump it has. The air slowly moved out of the clear tubes, and the exhaust has equal amounts of white smoke. (I don't know exactly what the volume and color of these exhaust gases should be so that remains a concern).

The pumps tested didn't pump, even with check valves installed on 2" tube. Finally got one to blurp out each port every second or two with full stroke control and 1500 rpm after soaking (priming) it in oil for awhile. (The stroke adjustment screw extends slightly beyond the jam nut). Doesn't seem right. Studied and understood how the pump works, even rebuilding them several times to familiarize myself with their function.

Perhaps these pumps don't squirt at all, but I have no way of gaging what the pump flow should be, so your experience is much appreciated. Thanks again guys.

Title: Re: Bench Testing 350 Oil Pump
Post by: BRT-GTR on April 07, 2018, 07:16:22 AM
         Hi Bob,
                  Sounds like your bike pump is working fine, you should get 350 miles per quart of oil as advised by Graham Weeks.
            The pumps don't 'squirt' oil, just 'burp' out a gentle slug from alternate outlets. Oil pressure is generated by spring on main rotor not power from engine as on a 4stroke. Black adjustment screw extends about 1mm from lock nut when correctly set.
       If she's smoking, she's getting oil. Too much smoke, screw in the adjuster 1/8 of a turn.
Title: Re: Bench Testing 350 Oil Pump
Post by: davis on April 08, 2018, 10:09:40 PM
Thanks for the confidence Brian. With this small amount of oil pumped I'm thinking oil flow is assisted by the crank case vacuum while the opposite side pressure is shut off by the check valve. Alternating vacuum action could offer a little steady assist in oil flow with check valves being indeed critical.
Title: Re: Bench Testing 350 Oil Pump
Post by: husker on April 09, 2018, 08:27:11 AM
Brian I came to the same conclusion last year while sorting out a pump problem. The slot is past the port so how does it pump?!.........Rod
Title: Re: Bench Testing 350 Oil Pump
Post by: davis on April 10, 2018, 07:22:10 PM
The cam with it's shaft moves up and down against the spring as controlled by the rounded end fixed pin. The resulting pump action causes a compression of oil at the cam shaft end. A tiny slot on the cam shaft piston end releases that pressure to the outlet ports while sealing the inlet port from releasing the pressure back through it. The oil distributor shaft is rotating at 1/2 the cam speed, thus in one revolution of the cam slot the distributor shaft rotates 180 degs. to hit both outlet ports alternately. This is why it is important to properly time the cam with the distributor shaft, since each outlet port passage should open up in time with high oil compression. The control lever also has a cam and moves the rounded cam guide to change the cam stroke action against the spring, thus reducing or increasing the volume of flow.

Anyways, that's the way I understand how it works. Hope this helps.