Author Topic: RE: CB750 Oil Pump Priming and Pressure Need Help (Read 11176 times)

chewbacca5000 · « **on:** January 29, 2012, 04:18:57 PM »

I finally got my engine on my 75 cb750 back into the frame and I primed the oil pump by submerging the entire pump in 2 to 3 quarts of oil then turn then gear till every last air bubble was out. I pump got more difficult to rotate once the air baubles were gone. I also used 1/2 inch heater hose to pour oil down into the galley through the plug under the points. I then kicked it over a bizillion times.

I tried holding my thumb over where the oil galley plug is expecting oil to shoot 15 feet, but this didn't happen. Should I have oil pressure? I am going to get an ignition switch so I will have the oil indicator light, but am thinking of getting an oil guage.

Much Thanks!

splitt · « **Reply #1 on:** January 29, 2012, 07:43:26 PM »

I laid my motor over on the stator side and removed the oil galley plug, I filled the oil galley with oil and reinstalled the galley plug. I pulled the spark plugs to make it easier to turn over. Then removed the valve inspection covers and liberally shot some oil on the cam/lifters to insure that they weren't dry.

I have an oil gauge mounted in the galley plug. It pushed down on the kickstarter by hand 12 - 13 times before the needle on the oil gauge began to rise. After that, I used the electric starter to turn it over. After I confirmed that oil was flowing from the camshaft journal area, I replaced the valve inspection covers, spark plugs and plug wires and fired it up.

That CB750 motor sat for over 14 years since it last ran.

chewbacca5000 · « **Reply #2 on:** January 29, 2012, 07:48:15 PM »

Much Thanks splitt! What oil gauge did you use? Can you recommend an oil pressure gauge. I did everything you suggested, but have no idea if it is working without a gauge.

Thanks!

bollingball · « **Reply #3 on:** January 29, 2012, 07:58:13 PM »

http://www.summitracing.com/parts/ALM-7122/?rtype=10 I like the oil filled one the needle doesn't bounce

ekpent · « **Reply #4 on:** January 30, 2012, 05:39:05 AM »

Never had an oil problem starting up these old beasts after sitting long periods and reviving. The best thing you can do is when you finally put some real fire to the 750 is to make sure your oil filler cap is off the tank,look into it with a flashlight and look for signs of circulation while running.First signs of circulation will look like some tiny bubbles and the level should drop.Not really good to lug or idle too low for first start either,around 2 grand or so will keep pressure up.

chewbacca5000 · « **Reply #5 on:** January 30, 2012, 05:42:29 AM »

Quote from: ekpent on January 30, 2012, 05:39:05 AM

Never had an oil problem starting up these old beasts after sitting long periods and reviving. The best thing you can do is when you finally put some real fire to the 750 is to make sure your oil filler cap is off the tank,look into it with a flashlight and look for signs of circulation while running.First signs of circulation will look like some tiny bubbles and the level should drop.Not really good to lug or idle too low for first start either,around 2 grand or so will keep pressure up.

Thanks for the tip! I will let you guys know how I make out. It should warm up soon and I will give it another go.

ekpent · « **Reply #6 on:** January 30, 2012, 05:46:55 AM »

Those first start ups can be a litte fretful. Done quite a few,just cross those fingers and give it heck. Sounds like you have prepped well for it

Make sure the idle adjustment on the carbs is set way low also so you don't have a screamer right out of the box.

chewbacca5000 · « **Reply #7 on:** January 30, 2012, 05:57:20 AM »

Quote from: ekpent on January 30, 2012, 05:46:55 AM

Those first start ups can be a litte fretful. Done quite a few,just cross those fingers and give it heck. Sounds like you have prepped well for it Make sure the idle adjustment on the carbs is set way low also so you don't have a screamer right out of the box.

This isn't actually a first start it was a good running motor till I ran into a shifting issue last summer and decided that it was worn shifting forks so I pulled the motor. While I was at it I added new orings to the counter shaft oiler and drilled the clutch hub for better oil pressure. I then put the whole thing back together without priming the pump. Pump is now primmed.

I got a gauge on order, but I may just turn it over with the electric and see if the light stays on. Will probably wait till it warms up in a day or so.

ekpent · « **Reply #8 on:** January 30, 2012, 06:01:43 AM »

Warmer oil would def be better than freezing.Throw a tarp over it with a little heater under it to warm it even more if its in an unheated garage. Suppose to be in the mid 40's here in Mich Tuesday--wierd winter around here this year.

wrenchmuch · « **Reply #9 on:** January 30, 2012, 07:09:05 AM »

You can check for oil pressure at the 1&4 exhaust side tappet caps . If you see oil there when cranking then you have the pump primed . When I've used the electric start with the plugs out I hear the revs drop when the pump becomes primed . Crank in short intervals . Don't overheat the starter . I've also had good results adding a little pressure to the oil tank with compressed air via the filler cap . This is more for when one forgot to prime the pump before installation .

Bodi · « **Reply #10 on:** January 30, 2012, 07:29:50 AM »

So what's up with the words spark plug in Splitt's post turning into links added by "viglink"? Is this some infection on my system or is it happening in the forum?

ekpent · « **Reply #11 on:** January 30, 2012, 08:53:57 AM »

Quote from: Bodi on January 30, 2012, 07:29:50 AM

So what's up with the words spark plug in Splitt's post turning into links added by "viglink"? Is this some infection on my system or is it happening in the forum?

I have that on mine also. Have been noticing a lot of words lately in threads,mine included, that are highlighted in a light blue I think it is, and want to go to a link ?? You are not alone.

splitt · « **Reply #12 on:** January 30, 2012, 06:53:05 PM »

OK, that's weird. I didn't put a link in that reply.

I found this on the internet though:

http://wordpress.org/support/topic/whats-calling-viglink

ekpent · « **Reply #13 on:** January 31, 2012, 05:43:25 AM »

Quote from: splitt on January 30, 2012, 06:53:05 PM

OK, that's weird. I didn't put a link in that reply.

I found this on the internet though:

http://wordpress.org/support/topic/whats-calling-viglink

Thanks for posting that but I am old and have no idea what the hell they are talking about.

chewbacca5000 · « **Reply #14 on:** February 04, 2012, 11:56:50 AM »

I have dropped the pump twice and submerged it in oil and turned the gear till there are no air bubbles at all still I can't get the oil light to come off. I have turned it over several times still the oil light will not go out. I ordered a gauge, but that is not coming till next week. I'd really like to get this bike running today. If anyone can help it would be most appreciated.

DH · « **Reply #15 on:** February 04, 2012, 12:16:44 PM »

Take the cap off the pressure port and put a catch pan nearby.
Crank the engine over in short bursts and see if oil squirts out.
You can do the same thing with the oil filter housing off. If oil pumps out, the pump should at least be trying. Remember,it takes several seconds for the oil lite to go out even after an oil and filter change.

MCRider · « **Reply #16 on:** February 04, 2012, 12:33:58 PM »

Quote from: chewbacca5000 on February 04, 2012, 11:56:50 AM

I have dropped the pump twice and submerged it in oil and turned the gear till there are no air bubbles at all still I can't get the oil light to come off. I have turned it over several times still the oil light will not go out. I ordered a gauge, but that is not coming till next week. I'd really like to get this bike running today. If anyone can help it would be most appreciated.

HAs this been discussed? Forgive me I haven't been thru the whole thread. But the oil light sender on these bikes is notorious for not working correctly. I think you can unscrew it and replace with an automotive style.

Maybe not.

chewbacca5000 · « **Reply #17 on:** February 04, 2012, 12:41:06 PM »

Quote from: DH on February 04, 2012, 12:16:44 PM

Take the cap off the pressure port and put a catch pan nearby.
Crank the engine over in short bursts and see if oil squirts out.
You can do the same thing with the oil filter housing off. If oil pumps out, the pump should at least be trying. Remember,it takes several seconds for the oil lite to go out even after an oil and filter change.

DH I pulled the pressure plug above the points cover turned the engine over with the electric start and not a drop of oil is coming out. Shouldn't I be getting something here?

DH · « **Reply #18 on:** February 04, 2012, 12:52:46 PM »

I'd see next if oil is being forced into the oil filter. I THINK that is the first place the oil goes to after the pump. Take the housing off and crank or kick engine and see if oil squirts out.

chewbacca5000 · « **Reply #19 on:** February 04, 2012, 01:02:29 PM »

I pulled the oil filter and there was oil in there, but when I turn it over I am just getting drips. Nothing that resembles a squirt. I don't mind taking the oil pump out done it twice already, and will do it again if need be. Just want to have oil pressure.

DH · « **Reply #20 on:** February 04, 2012, 01:18:27 PM »

Not sure how much volume there should be, but the pump SHOULD
be able to flow oil to the filter. Maybe cranking engine with plugs out will give pump enough speed to pump good volume. Anyone else have an Idea? Personaly, I'd try running it for a short time if
I knew the top end was oiled, and see if the pressure builds.

chewbacca5000 · « **Reply #21 on:** February 04, 2012, 01:34:36 PM »

DH I may have to run it to see if pressure builds. I just wish there was a way to verify proper operation of the pump off the bike. If I place the pump in a couple quarts of oil and turn the gear should I feel pressure build on the delivery port, which is next to the oil stopper valve? Shouldn't I be able to cover this port with my thumb spin the gear and feel pressure? Thanks! Anyone else know how to test the pump?

ekpent · « **Reply #22 on:** February 04, 2012, 02:21:05 PM »

You may be over worrying about it. You said it was a runner before you took it apart.Kicking and cranking won't really build the pressure and flow like it will when it actually starts and runs. Start it up and as I mentioned before be looking into the oil tank with a flashlight and look for signs of the oil moving,tiny bubbles and the level dropping.Don't let it idle too low,you want the oil to move well. Your going to be driving yourself crazy until then.

chewbacca5000 · « **Reply #23 on:** February 04, 2012, 02:31:34 PM »

ekpent,

I think your right on the money. It's probably not going to build enough pressure from kicking are cranking to do much of anything let along shut of the oil light. Think I am going to take a break get some dinner and maybe have a round two, or tackle it further tomorrow.

ekpent · « **Reply #24 on:** February 04, 2012, 02:50:43 PM »

Fire in the Hole

DH · « **Reply #25 on:** February 04, 2012, 08:19:53 PM »

Quote from: ekpent on February 04, 2012, 02:50:43 PM

Fire in the Hole

X2- I'm with ekpent

chewbacca5000 · « **Reply #26 on:** March 11, 2012, 06:34:07 AM »

I know it's been awhile since I updated this thread, but I have been working on getting my HEI setup to run. While doing my spark testing I got oil pressure back! When I went to adjust the gap on the pickups I noticed a nice stream of oil running out the side galley plug.

Another SOHC problems solved thanks to all for the help.

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Author Topic: RE: CB750 Oil Pump Priming and Pressure Need Help (Read 11176 times)

bollingball

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