Bridgestone Motorcycle Parts Discussion Board
Bridgestone Tech Talk => 350 Talk => Topic started by: davis on April 03, 2018, 02:38:12 PM
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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.
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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.
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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.
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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 ,
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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.
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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.
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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.
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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
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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.
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Adding to this forum, I have done similarly to what most of you have said and mixed my gas in my tank and have been testing the oil pump on the bike itself. However I too am having issues with my oil pumping properly and I imagine the issue is because of the cam not adjusted correctly with the black adjuster screw at the end. My question is, how do you know what the proper adjustment is of that screw? The left cylinder pumps perfectly fine, but on occasion the right side stops pumping at random, puts an air pocket in the line, and continues to pump. Seems that the manual has no directions on how to set this. Thoughts? Thanks for any help.
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that may not be sealing properly check the gaskets /connections ,there should be some old posts on the siteabout that
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Oil Pump Setting :-
Rough check - Tip of black adjuster screw projects approx 1mm from lock nut.
Full check - Use oil pump rebuild guide by Graham Weeks here - http://bridgestonemotorcycleparts.com/index.php?topic=3629.0 (http://bridgestonemotorcycleparts.com/index.php?topic=3629.0)
Fact that left side pumps fine says your pump is working as it should.
The air bubble on the right side can only be sucked into the pipe, likely by the crankcase vacumn as the piston rises.
You have an air leak, probably due to a split in the oil pipe or at the outlet union on the pump. Don't overtighten the banjo screw, can strip the thread in the zinc pump body. Replace aluminium washers or apply sealant carefully.
You are not on your own with this issue. The pumps are very reliable :D when sorted but making the system oil/air tight can be a pain in the ass !! >:(
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Bonded rubber washers solved my pump leakage problem. McMaster-Carr #93786A125 (High-Pressure-Rated Metal-Bonded Sealing Washer for M6 Screw Size, 5.8 mm ID, 11.3 mm OD). Need to replace a leaking drain plug washer with this type. Since the 350's seemed to seal well from the factory,it appears reused aluminum washers have a problem.
Cheers! Off to the U.K., but no Isle of Man this time.
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On a side note, when I pull the oil pump off the bike and the oil from the pump side/side that mounts to the motor drains out, should I be finding transmission oil or injection oil? Seems like I may have a bad seal on the inside... :o
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Transmission oil. There isn't a seal on the shaft separating the transmission from the oil pump.
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No but there is a seal between the injection oil distributer and the transmission oil side, I believe that's bad and may be causing part of my issue with my air leak. If I wanted to temporarly stop the oil injection and run premix until I find the correct seals, what would I need to do? Can I just stop the flow of oil from the reservoir to the pump, or do u need to replace the check valves with solid bolts to prevent it from drawing air after the flow of oil is cut off. Thanks for all of help!
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GTR oil pump overhaul kit available from the UK here :-
https://www.ebay.co.uk/itm/Bridgestone-350-GTR-350-GTO-oil-pump-rebuild-kit/111702090764?hash=item1a01f6a40c:g:cb0AAOSwuMFUbyfz (https://www.ebay.co.uk/itm/Bridgestone-350-GTR-350-GTO-oil-pump-rebuild-kit/111702090764?hash=item1a01f6a40c:g:cb0AAOSwuMFUbyfz)
Contains the distributor valve seal if you can't source in the US.
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Currently in the middle of rebuilding the pump after buying the rebuild kit from the UK (seems I couldn't sorce the seals in the states), but as I'm reassembling I have found that the the spring for the oil pump is either missing or just misplaced. Does anyone have any pictures of the pump interals or at least some dimensions of that spring. I have a spring that I am almost positive is the one for this, but I don't want to have to tear this pump apart again in the instance it is wrong. Thanks :D
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Hi BSB,
Great job on the bike and engine, keep up the good work !! Full marks for having a go yourself. We don't know what we can't do until we've failed a number of times (doesn't apply to parachuting and hang gliding :D ;D :D) but even then we are learning all the time.
Spring is 21mm long x 5mm diameter. Brian.
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I come to the forum once again. This oil pump is proving to be extremely difficult and I have found no solution yet. I did just rebuild the pump with a kit from the UK, but only the right side is drawing air. I have switched the banjo bolts, bight new banjo bolts, bought new seals for around the bolts, double checked everything. The left side/cylinder draws no air from the pump. I did however see that at one point air was actually pushed BACK from the check valve on the motor into the oil line. Maybe these two are somehow related?
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Are you sure the distributor valve is correctly timed to the main pump rotor as shown in Fig 94 in manual. (I'm sure you've checked it many times). Ignore fig 93, no-one has yet worked out what that refers to !!
See aslo service letter BSG-0059, Page 32 here ------- http://bridgestonemotorcycleparts.com/PDF/BSServiceLetters.pdf (http://bridgestonemotorcycleparts.com/PDF/BSServiceLetters.pdf)
Air being pushed back toward the pump suggests the checkvalve is not working correctly. Don't take the checkvalve out unless you absolutely have to or have already taken it out. The 8mm threaded section is very weak and often breaks, that will cost you. Test it by sucking on the oil line, there should be no backflow whatsoever from the crankcase. Blowing forward, you should feel a slight restance, then the ball will be pushed off its seat and forward flow is allowed.
If not functioning as above, rinse the valve in kerosene until it clears. Don't put an airline on it, that will destroy the spring inside. Brian.
Would also add, is the flow of oil from the tank OK. Check the brass mesh filter on the tank banjo bolt. Can become blocked over time.
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My pump seems to be working fine on a running motor. Just came across the spec. Seems only 1 cc/min. is the flow rate at my 1,500 rpm test rate is all that I could expect (see engine manual pg. 76).
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The confusion continues....
I decided that I wasn't sure how much I trusted the one check valve, so I decided to switch it out with a second one I had, since you can only buy them in a pair from richard. After switching the valvue, the pump seemed to work great. I let the bike sit for 20minutes or so running, no air leak. I then took the bike out for a ride and came back no air leak. Came out and started the bike up again this morning, ran for about ten minutes, still no air leak. I walk back after mixing up another gallon of gas, there is an air bubble. The pump is not consistently sucking air, but on just rare occasion it sucks air. This inconsistency has me very confused. And yesterday I did reset the timing on the pump and double check everything....what on Earth is going on? :o I feel if it was something to do with motor timing or vaccume leak it would be consistent and the bike would not run as good as it does.
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To add, the oil line from the tank is perfect and the line running to the left cylinder is perfect. I just took the bike for a test ride and it drew oil to both sides perfect. Yet as soon as I slowed down about to park it, it started drawing air ONLY ON THE RIGHT SIDE once again. It also seems that when I manually bleed the lines by lifting the lever on the pump, that seems to add a very tiny bubble or two.
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As air is introduced when you lift the control lever, check the pump back plate is still fully tightened (Black item that carries adjuster screw and has left hand thread). This can loosen when locknut is tightened or throttle is used.
As for air in right side line, logic says it can only enter the system between the distributor valve and the engine check valve otherwise it would affect the left side. My money is still on the banjo seals on the pump, does air appear at the banjo outlet. Don't trust the flat alloy washers to seal, better solution is 'dowty washers' that have a built in rubber seal. Banjo bolts can bottom out on their thread before washers are fully compressed. Hair line crack in the banjo ?, these are known to suffer degradation of the alloy under damp conditions.
Beyond the above, I am stumped and suggest you try another pump although that could introduce further issues. Keep going, you are nearly there.