Author Topic: RE: 1973 1st Start Ater Rebuild - Getting Oil Pressure (Read 2254 times)

chewbacca5000 · « **on:** May 14, 2012, 01:18:37 PM »

Ok I finally got my 1973 CB750 engine all together and back in it's home. Now I am not sure I have oil pressure or not. My oil light does not seem to be working. I didn't take the pump this time, but may have lost prime from moving the engine around.

Is there any way to fast track this process so I don't have to turn the engine over a million times to get pressure back?

Thanks!

chewbacca5000 · « **Reply #1 on:** May 14, 2012, 03:35:05 PM »

Ok, I dropped the oil pump in the 2 quarts of oils and turned the gear till it burped up some air bubbles, put it back and and still no oil running out the oil filter. I know it starts here say it on my 76. When I primped my 76 it took several tries all it all up and it seemed like hours. I don't want to mess up my freshly rebuild engine by laying on the start button for the next 3 days straight.

I the good news is a quick compression test shows 160 on both 1 and 4. Never see identical so that makes me happy. 170 would have been better. Also, my hands won't rust anytime soon.

cben750f0 · « **Reply #2 on:** May 14, 2012, 04:50:00 PM »

the compression, should rise as the rings bed in

peace

regarding the oil pump, if it has oil, take the plugs out, take the inspection caps for the rockers off, and see if there is oil in the top end.....its what i do?

just a suggestion

peace

chewbacca5000 · « **Reply #3 on:** May 14, 2012, 04:59:57 PM »

Quote from: cben750f0 on May 14, 2012, 04:50:00 PM

the compression, should rise as the rings bed in

peace

regarding the oil pump, if it has oil, take the plugs out, take the inspection caps for the rockers off, and see if there is oil in the top end.....its what i do?

just a suggestion

peace

There is just the oil I put there originally. No oil is flowing out the filter. I had the same problem on my 1976 after replacing the orings. Took days before the oil would start to flow. Can I just dump some oil in the top end to keep it from getting fried and fire it up.

Not sure the starter is enough to get thing going? I put a ton of work into this engine, boring, surfacing, HD Studs, HD Nuts, pistons, serdi valve job and don't want to hurt anything.

wrenchmuch · « **Reply #4 on:** May 14, 2012, 07:14:28 PM »

Try this . Its worked for me .

http://forums.sohc4.net/index.php?topic=105999.msg1185531#msg1185531

chewbacca5000 · « **Reply #5 on:** May 14, 2012, 07:29:08 PM »

Quote from: wrenchmuch on May 14, 2012, 07:14:28 PM

Try this . Its worked for me .

http://forums.sohc4.net/index.php?topic=105999.msg1185531#msg1185531

Thanks wrenchmuch I will give air pressure a go and report back.

chewbacca5000 · « **Reply #6 on:** May 14, 2012, 08:12:41 PM »

Wrenchmuch didn't have an assistance to press the start button so I tried leaning it way over on it's side stand and am getting oil to flow to the filter housing. Do you think I am green light to fire here up?

wrenchmuch · « **Reply #7 on:** May 15, 2012, 07:29:10 AM »

Put the filter on and crank it with the plugs out till you see oil at the 1 and 4 exhaust valve adjustment caps. You will be ok to start then.
Good luck
Mike

chewbacca5000 · « **Reply #8 on:** May 15, 2012, 01:03:29 PM »

Thanks Wrenchmuch! I guess it would have helped if I were looking on the exhaust side instead of the intake side since the oil runs down that way. I will check it out and report back.

Thanks!

chewbacca5000 · « **Reply #9 on:** May 15, 2012, 06:45:56 PM »

Ok, cranked over after taking my 76 out for a ride to get my daily fix and started to seem some oil in the exhaust side tappet number 4. Not a lot but a little. Then I noticed oil where I left plug lose on the oil galley so I took the plug out and there was alot there. Think I am ok here.

Do you think filling the top end helps with the initial flow. I really got to look at a diagram for the oiling system I think it will help me make better sense of things. Much Thanks!

wrenchmuch · « **Reply #10 on:** May 16, 2012, 06:43:11 AM »

If you see oil at the exhaust covers its already lubing the bearings and cam . You should be good to go .

elbowdeep · « **Reply #11 on:** May 16, 2012, 07:44:10 AM »

Would engine assembly lube prevent this concern? Just a thought...

Don R · « **Reply #12 on:** May 16, 2012, 10:27:38 AM »

Assembly lube would certainly help, On a dry engine I like to remove the galley plug where the aftermarket gauge fits, use the gauge adapter and screw on a pipe elbow and then a reducer going up to a 3/4" x 6" nipple then I fill the oil galley from above. I also add oil into the rocker covers. Replace the plug before starting.

chewbacca5000 · « **Reply #13 on:** May 16, 2012, 12:53:33 PM »

Don,

Have you ever thought about trying to use a pump in the side galley instead of the hose? I am thinking that all the passages need to be filled before oil can travel to the top end. Adding oil to the top end makes sense as it will just go back down and fill more stuff up right? Same with the hose for the side galley. Is my logic sound on this?

MCRider · « **Reply #14 on:** May 16, 2012, 01:29:21 PM »

"Do you think filling the top end helps with the initial flow." Not really. Once its in the top end it has no pressure. Any oil there whether from engine flow or from you, will just drain from gravity down to the oil pump sump and get pumped back to the tank.

chewbacca5000 · « **Reply #15 on:** May 16, 2012, 05:04:44 PM »

Thanks MC that helps. What about injecting oil into the side Galley other members seem to think that has helped them what are your thoughts on that?

wrenchmuch · « **Reply #16 on:** May 16, 2012, 05:57:23 PM »

Pumping oil into the side galley would certainly send oil to the crank and head but this doesn't substitute for checking for flow at the head using the engines pump .
I'm not sure that pressurizing the side galley port will ensure the pump gets primed if there was air in it to begin with . Anything that spins or moves that gets disassembled for repair should have assembly lube applied to it . If the engine sits for a while after assembly you don't need to worry about oil creeping out of areas that need lubrication at start up . If you see oil at the exhaust tappet holes while cranking , everything in the head is getting oil . You can't get oil to the areas that need it most (cam shaft bearings , cam lobes ) by pouring it into a tappet hole .

chewbacca5000 · « **Reply #17 on:** May 16, 2012, 06:15:36 PM »

Thanks Wrenchmuch. Isn't a rule of thumb of how long it takes to get the pressure back after taking the pump out for inspection / repair. How long does it take you usually to get he oil up to the tappet hole on the exhaust side? I want to learn how to do this quicker so I can improve.

wrenchmuch · « **Reply #18 on:** May 17, 2012, 05:36:54 AM »

The last time I re built an engine it took a minute total of cranking to get pressure up. I've been toying with pumps (replacing seals, lapping pump body sides to reduce rotor side clearance ) and ended up needing to prime them after installing as I forgot to prime them. I ran into the tread about putting some pressure into the tank. It's worked twice for me now. Once I have pressure from the pump I see oil at the head about 20 sec later. The area where the cam sits will need to fill with oil before it spills over the cam bearings and makes its way to the front of the head.

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chewbacca5000 · « **Reply #19 on:** May 17, 2012, 05:51:07 AM »

Quote from: wrenchmuch on May 17, 2012, 05:36:54 AM

The last time I re built an engine it took a minute total of cranking to get pressure up. I've been toying with pumps (replacing seals, lapping pump body sides to reduce rotor side clearance ) and ended up needing to prime them after installing as I forgot to prime them. I ran into the tread about putting some pressure into the tank. It's worked twice for me now. Once I have pressure from the pump I see oil at the head about 20 sec later. The area where the cam sits will need to fill with oil before it spills over the cam bearings and makes its way to the front of the head.

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I am here: http://tapatalk.com/map.php?xnufce

Ok, why does the air pressure thing work? Does it force oil down into the pump? Could this be an issue with the valves in the pump not opening easy enough?

So your near Toronto? Are you going to do the realay. I think I am signed up from Buffalo to who knows where? Should be alot of fun.

wrenchmuch · « **Reply #20 on:** May 17, 2012, 08:44:50 AM »

Relay? When I used air pressure in the tank it worked both times. I just put my fingers over the tank fill hole and put the air chuck between my fingers. I also put a vice grip on the tank vent hose to keep pressure in the tank. Air will leak around your fingers but it takes very little pressure to get the oil to move down and displace the air. Do this with the plugs out. From earlier posts it seems you've go the pump primed if you get oil at the filter housing. Don't delay. Start it today ( if you see oil at the exhaust tapper holes ) .

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chewbacca5000 · « **Reply #21 on:** May 17, 2012, 02:58:57 PM »

Quote from: wrenchmuch on May 17, 2012, 08:44:50 AM

Relay? When I used air pressure in the tank it worked both times. I just put my fingers over the tank fill hole and put the air chuck between my fingers. I also put a vice grip on the tank vent hose to keep pressure in the tank. Air will leak around your fingers but it takes very little pressure to get the oil to move down and displace the air. Do this with the plugs out. From earlier posts it seems you've go the pump primed if you get oil at the filter housing. Don't delay. Start it today ( if you see oil at the exhaust tapper holes ) .

No sorry the SOHC4 bike relay. I got oil pressure and am fine on this issue. Think the relay is coming to Update NY in August and since your near Buffalo was wondering if you were going to join in. Maybe they go right through toronto.

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Author Topic: RE: 1973 1st Start Ater Rebuild - Getting Oil Pressure (Read 2254 times)