Author Topic: One problem after another, no oil pressure (Read 1815 times)

samm_j2 · « **on:** July 16, 2021, 05:14:57 PM »

ekpent · « **Reply #1 on:** July 16, 2021, 07:42:42 PM »

Only thing I can add is that on a stock 750 oil tank you can definitely see movement of oil and bubbles etc when peering inside while running. I always peek inside on new project start-ups for the first time to make sure oil is moving. Hope you get it sorted out.

markreimer · « **Reply #2 on:** July 16, 2021, 07:46:02 PM »

Drop the pan, what’s the pickup screen look like?

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ekpent · « **Reply #3 on:** July 16, 2021, 07:51:49 PM »

Think he already dropped the pan. One other question. When you rebuilt and hopped up the engine did you replace the cam chain tensioner, the rubber wheel etc.. There was a bad batch of Chinese ones being sold by some of the large online part houses that were failing. Might be some of the rubber type of material you found.

samm_j2 · « **Reply #4 on:** July 16, 2021, 08:00:48 PM »

Thanks for the replys,

I have dropped the pan, there is some metal flakes down there... the screen caught some.. but engin was pulling really strong. I did replace the cam chain tensioner and it was just off ebay... may have been a bad one. Pulled cam cover and look as best I could but from what I saw it seemed fine, no major broken chuncks.

Current plan of action is to rebuild the pump and see whats up... I took the pump apart and there were two small metal flakes that were in there. The scavenger gears have some clearance, one side as .010" which is still in spec I think. There is some wear and very slight putting in the gears... gonna order a kit here tonight. Do I go with cycle ex $70 or go with a 20 buck kit from cb750.com?

Appreciate anyone with any ideas

Thanks again

scottly · « **Reply #5 on:** July 16, 2021, 09:19:20 PM »

My thought is that the custom oil tank is not working very well?

samm_j2 · « **Reply #6 on:** July 16, 2021, 09:37:54 PM »

Haha thanks scottly, I know what you mean. Due to the mono shock in the bike I am left with few options on where to put an oil tank...

samm_j2 · « **Reply #7 on:** July 16, 2021, 09:43:57 PM »

There were a few small metal flakes inside the oil pump, here is a pic of one of the scavenger gears... how bad is this? I am guessing new(er) gears are needed off a different pump? Or maybe just a different pump?

The inner shaft seal was super hard and broke really easily and now I am having a hell a time getting the rest of it out...

samm_j2 · « **Reply #8 on:** July 17, 2021, 06:42:20 PM »

does anyone know if it is fine to mix parts from oil pumps? mainly the gears? I went to the pick n pull yard this morning and found a pump that spun, the only apparent difference is the locking pin is longer and the key way cut in the gear is longer to accommodate said pin. I assume that I can use these or the old pump or whatever combination has the tightest tolerance and fit... but assuming seems to get me in trouble.

thanks

754 · « **Reply #9 on:** July 17, 2021, 10:33:23 PM »

Back to begining. Do you have a stock bucket and oil lines to try ? ...., when you get pump back together..
I mean for testing purpose.. tie or wire it to your frame.

bryanj · « **Reply #10 on:** July 18, 2021, 12:10:56 AM »

Rotors should only be used as pairs and idealy if used a complete pump only

PeWe · « **Reply #11 on:** July 18, 2021, 01:16:11 AM »

If top end went bad due to no oil delivered from tank during a longer period of time, crank bearings and journals might be bad.
If they are, next is rod bearings and journals.
If this is the case, open the lower case and inspect is next to be sure.

samm_j2 · « **Reply #12 on:** July 18, 2021, 07:04:15 AM »

PeWe,

You mean split the case right? After doing that is there a way to "inspec" the crank bearings and journals without taking off the rods? I would imagine i have to remove the rods to inspect right?

Thanks

PeWe · « **Reply #13 on:** July 18, 2021, 07:18:05 AM »

You will see crank journals and bearings when lifting the lower case.
If these look fine, rods with journals are most likely fine too. I guess the inner shells are worn if any.

Good idea to use assembly lube on crank bearings and cam/rockers. It will lubricate well until pressure is stabilized at first startup.
I use Red Line. Last one is the fluid type. "Red Line Liquid Assembly Lube".

Lucas has a similar product but more sticky and smells good. Must be good when building an engine to be stored for future use.

samm_j2 · « **Reply #14 on:** July 18, 2021, 08:07:32 AM »

754, ya man, I still have the stock oil bag and lines... that is not a bad idea at all!

PeWe, Do you think it would be worth it to rebuild the pump and then check oil pressure at operating temps before splitting the case? wont hot oil pressure let me know if main bearings are good? I think I read from honda man above 40psi at 2500 rpm? Or your vote is to just split the case to make sure?

I will say on the pump that the inner shaft seal was beyond dry and brittle, the oring on the pressure relief was flatter than a flap jack, and the oring around the dowel pin on the intake was loose and not snug...

regardless there was a loss of pressure to starve the #1 lobe on the top end.... at least that damn ticking is gone... I do not want it to come back!

thanks again everyone!

754 · « **Reply #15 on:** July 18, 2021, 09:02:09 AM »

First off, get another pump, it should bolt on, yours has several things wrong, maybe someone was in it already.
Onece another pump is in, you can try it with the stock tank, if the lines can work.

Medyo Bastos · « **Reply #16 on:** July 18, 2021, 09:10:44 AM »

Just change the oil pump!

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PeWe · « **Reply #17 on:** July 18, 2021, 09:32:45 AM »

Are you sure that pump is that bad?
- I have never read about pump causing bearings/cam failures.
- Maybe if not properly assembled where kick starter shaft with its sprocket was removed so pump did not spin at all.
Remove kick start completely for look only, not a great idea unless the shaft is there with sprocket connecting pump with main shaft behind the clutch.

- Wrongly assembled (flipped) overpressure valve caused way too high pressure is another issue I have heard about.

I rebuilt both my bikes pumps when new rotors were available for OK price. They got new o-rings, and seal at the same time.
Plus rubber part inside the valve that stop oil to flow to engine when powered off.

But if oil warning flicker at idle, increase the rpm. 1200 work fine and easier to ride.
If really hot outside use thicker oil. I had a really hot summer 2018 where I used 20W-60 into the mix due to steady +32 C
20W-50 was not enough. High quality motorcycle oil.
Higher compression helped to heat the oil to 120C.

Oil pressure warning a very important functionality. It should switch off the ignition after 5s if no pressure just for sure. Another relay?

My K6 has 5 relays. I have just found relay no 6. But it can fail and stop the bike.

samm_j2 · « **Reply #18 on:** July 18, 2021, 01:13:16 PM »

Update:

I decided to test my oil pressure gauge. Figured it would be off somewhat but it was off by ehat seemed to be a lot but maybe it is normal for these lil things. At 10psi of air pressure the needle was not moving. At about 15-20 the needle shot up to maybe 5psi on its gauge, at 80psi of pressure the gauge read about 70-75psi. So it was constantly reading low...

This is somewhat reassuring as when the gauge read 0 but the dummy light was not on it still had good pressure while at idle and running.

ekpent · « **Reply #19 on:** July 18, 2021, 02:39:34 PM »

Glad I don't own any bike with an oil pressure gauge. I'd probably crash into a tree or miss a curve or something else looking at it too much.

754 · « **Reply #20 on:** July 18, 2021, 06:23:03 PM »

I am alwats amazed when people say that.l
Do you ever blink ? Lookat scenery. . Look behind to see where others are ?
You dont need to always know your pressure, just a glance to see if its off the lower end of scale..

PeWe · « **Reply #21 on:** July 19, 2021, 12:07:17 AM »

Like watching at hot chicks beside the road, a quick memory photo and drool without crashing the bike!

The pressure gauge work better than I thought.
While riding as parked when engine is just started or really hot.
Good to check now and then.

ekpent · « **Reply #22 on:** July 19, 2021, 06:14:34 AM »

Quote from: 754 on July 18, 2021, 06:23:03 PM

I am alwats amazed when people say that.l
Do you ever blink ? Lookat scenery. . Look behind to see where others are ?
You dont need to always know your pressure, just a glance to see if its off the lower end of scale..

I wrote that kind of tongue in cheek. I had just read prior to the post about this 72 year old biker wearing a helmet who had died earlier after slamming into the back of a car on a major highway near here while traffic was slowing down.Things can happen very quickly if your not on your toes.

PeWe · « **Reply #23 on:** July 19, 2021, 07:05:52 AM »

Keep the distance to the vehicles in front of you.

Understanding when you have to focus on that which is the difference when a biker will continue to ride or not.

Very often better to twist the throttle and clear the road when people are driving erratically.

My dyno guy had long delays last year in April. He broke both arms when riding and collided with the car in front of him. Traffic suddenly stopped, he did not focus on traffic, not oil pressure gauge

Harley.....

Same when looking at speedo, tacho.
Female drivers can suddenly brake if seeing something beside the road.

Oil gauge and warning light are important. The red light must work.

ekpent · « **Reply #24 on:** July 19, 2021, 08:39:46 AM »

Without totally hijacking the thread I can give one more warning from personnel experience. I guy I know last year got it bad on a vintage BMW. He was following a bigger box truck and a lady was turning. She must have assumed that when the truck was past she could turn left but when she did she lo and behold there was the Beemmer. Maybe if he had been laying back a bit she might have seen him better or he may have had more time to react.
Alright back to that oil pump or tank or bearings etc..

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Author Topic: One problem after another, no oil pressure (Read 1815 times)