No oil pressure

[Skeller]

Hey,
rebuilding a 1979 gs 1000.
I had to split the cases to get a broken bolt out.
new piston rings and oil seals and gaskets while I was in there,
finally got it back together and in the bike.
problem is, no oil pressure and no oil getting to the top of the engine .
i did all the work myself, only because I was un able to find anyone local who would work on it.
I am just turning it over with the starter motor.
haven't attempted to run it yet.
any way to test the oil pump?

[Suzukian]

I'd would split those cases and start over again and make sure every passage way is not blocked, the bearings are seated properly, the oil pump is operating and hooked it properly. It's the only way ti prevent a catastrophic failure, and possibly loose the complete engine. Every engine I have ever blueprinted started up on the first shot, with full oil pressure. If that hadn't happened, I would have removed the valve cover, it if was dry, I would have taken the motor back apart. I build using a lot of assembly lube, in the event something like that ever happened. There's really no way to check the oil pump, that's done when it's in your hand. No oil at the top end means something is not put together right. It could be something simple. What you have to do is the same, take it apart, and reassemble it, and be very meticulous about what you are doing. To the point that when it is assembled, turn it over a few times by hand, to make sure the engine is turning smoothly, having the timing and carbs adjusted as well as you can, then try and start the bike. IMHO

[Nessism]

There is a large galley plug just above the ignition cover, at the back of the cylinder. You might want to pull that plug and crank the engine so see if oil is flowing. If not, maybe try pumping some oil into the galley to prime the system and try again. If none of that works, the oil pump is behind the clutch hub. You might want to inspect the drive gear to make sure it's spinning the pump as expected.

[Agemax]

No need to split the cases or tear down the motor. As Nessism says, pull the clutch off and inspect the oil pump and drive gears.
Make sure the drive gear is meshed properly with the clutch hub.
Plenty of things to check before stripping the motor, which can all be done with the engine still in the frame.
Make sure you have enough oil in there!

[Brendan W]

+2 for checking the clutch basket engagement with the pump drive.
When I got my 850 the oil pressure light came on at idle when leaning right and on the overrun.
Leaning left at idle or engaging gear put it off.
Clutch was assembled wrong and the helical gears popped the basket on and off of the pump drive with the help of gravity and gear load direction.
Could you have used a bit too much threebond to locate the pear shaped o-rings at the base of the gallery risers to the head.........damhik

[uk gs nut]

When the cases were put back together, is the thick O ring on oil gallery sitting properly?. As said is the oil pump turning with engine cranking. Remove the clutch hub and turn the pump manually with the oil gallery plug at lower right of cylinder block out. The bike can be on side stand and not much oil will be lost, put a bit of 4×2 under front wheel to lean bike over.

[KiwiAlfa156]

Just a few thoughts. How long have you cranked it for? If you've split the cases, then all the galleries and the oil filter cavity will be bone dry. It can unnervingly take about 5-6 sec to fill once the engine starts in this state, showing zip oil pressure until the filter cavity is full. Have you checked the continuity on the oil pressure switch? Has the oil level dropped during the cranking? I've just primed the oil galleries and filter cavity in my 750 rebuild by rotating the crank by hand with a spanner and the oil went from full on the sight window to below the "L" mark and took 30-40 crank rotations.

Ditto on the advice of removing the main gallery plug, and (manually) turning the engine to check for oil flow. This will confirm the pump is meshed and turning and pumping oil. You can also take the cam cover off and check for oil flow which will be oil weeping from around the camshaft journals while (manually) rotating the crankshaft.

Good luck.

[Supercub]

It may just need priming as above. Even just doing an oil change, it takes a while to pressurize the system to get sender feedback. You could add a gauge to use until its sorted.

[Nessism]

When the cases were put back together, is the thick O ring on oil gallery sitting properly?. As said is the oil pump turning with engine cranking. Remove the clutch hub and turn the pump manually with the oil gallery plug at lower right of cylinder block out. The bike can be on side stand and not much oil will be lost, put a bit of 4×2 under front wheel to lean bike over.

This ^. If you forgot the large O-ring between the case halves, you are going to have to split the cases and install it.

[bitzz]

You can prime the oil pump through the oil pressure sender hole. Remove the sender and SLOWLY pour oil down the hole.
Then remove the gallery plug on the right side, turn over the motor and see if you have oil flow. Remember this motor doesn't have a lot of pressure

[Suzukian]

I recommended splitting the cases because he just had the engine apart. That oil pump should self prime the system, it should need no priming whatsoever. As Nessism said, if the O-Ring is not there, or is pinched, or somehow not sealing, you won't get oil pressure, and if you do start the bike, it will seize up on you. I don't think you can see the condition of that O-ring behind the basket and gear. I've never had a motor I've rebuilt completely have no oil pressure. I have spun them up without plugs in them, or any electronics, and the top cover off, and see the oil come up. You liked the bike enough to split the cases and rebuild it, why take the chance now? Good luck on whatever you choose to do.

[Skeller]

Thank you for all the great advice.
I overreacted due to the fact that I have no engine building skills, other than 2 stroke dirtbike top end replacement.
somehow I had it in my head that the oil capacity was 2.5 liters.
after checking the manual, put the other 1.5 liters In.
now i have oil getting to the camshaft.
just thought i would check the easy stuff first.
Duh...

[allojohn]

Hey man, don't you worry... that's a win!

[Suzukian]

That's a real good win!! Sometimes it's the simple things, but we all learn from our mistakes.

[rphillips]

Ooohhh, that's great, and all it took to fix it was a little embarrassment and a qt. or so of oil... I sure wish my problems got fixed that easy.,, Congrats. Don't forget to give us an update when you get it running and dialed in. Seems you're almost there.