Topic: NO OIL return after complete motor rebuild?

[mario medeiros]

I did prime the pump before it was reinstalled,removed plugs and the rocker cover and have cranked the motor over and over and no oil is returing to the oil tank and i don't see the oil level going down in the tank.And i did remove the return line so i can watch to see if oil is coming out and nothing.Should i pour a half liter of oil down the motor where the cam chain is to grt oil down to the bottom of the motor?also i removed the feed line at the bottom of the motor to make sure oil was leving the oil tank and it is.BTW is a 1972 cb750 thanks

[ekpent]

Might need to officially start it up and cross fingers to really get things moving while monitoring the inside of the oil tank.

[Elan]

I and others had to remove the galley plug on the right side,1:00 from clutch, and fill that with oil. You have to lean the bike to the left. 
750 right?

[mario medeiros]

Is that the plug where you would install a oil presser gauge?

[ekpent]

yes. They also make an oil pump that can be hooked up there to power prime.

[70CB750]

Aha, that's what the 1:00 means, i am thick headed today 

[Jerry Rxman Griffin aka MuthaF'er]

I added oil to the '1:00' and the top end. I did NOT remember to prime the pump. No dice UNTIL I fired her up and only then did I finally get oil flow. I did use assembly lube  Boy, was I worried initially.

[mario medeiros]

I have a seringe i use for oil,i will get some oil in there,also do i dump some oil down the cannel where the cam chain is as i have the cover off?

[lucky]

You will get no oil pressure showing on the gauge until it actually starts.
Electric starter will not get results.

[70CB750]

Here we go again, electric starter WILL get results.  I am going to make a video of the oil gauge after I change oil.  I run the starter with kill switch off till the oil gauge shows value and the oil light switches off.  It takes a while, but that's how I know after  every oil change, that it is safe to start the engine.

[Don R]

Here we go again, electric starter WILL get results.  I am going to make a video of the oil gauge after I change oil.  I run the starter with kill switch off till the oil gauge shows value and the oil light switches off.  It takes a while, but that's how I know after  every oil change, that it is safe to start the engine.

He's not talking about an oil change, he had the engine apart. When you change oil some will stay in the pump.

[mario medeiros]

Came home,removed my oil gauge and with a syringe added some oil into the hole,turned over the motor with the elec starter with the return oil line hanging down and still no oil coming out of the line?

[Elan]

Came home,removed my oil gauge and with a syringe added some oil into the hole,turned over the motor with the elec starter with the return oil line hanging down and still no oil coming out of the line?

DId you tilt the bike and add it? a syringe wouldnt be enough, you have to fill it. Took me about 12 ounces.

[70CB750]

Here we go again, electric starter WILL get results.  I am going to make a video of the oil gauge after I change oil.  I run the starter with kill switch off till the oil gauge shows value and the oil light switches off.  It takes a while, but that's how I know after  every oil change, that it is safe to start the engine.

He's not talking about an oil change, he had the engine apart. When you change oil some will stay in the pump.

Does not matter, lucky is sure no matter what that starter can't build enough pressure to turn of the oil light.

[Nic]

On my complete rebuild ( 750 ) the starter got my oil light to go off.

[ekpent]

Sooner or later your going to have to just start it up, I know its scary.

[PeWe]

I'll do the same thing soon. Bike has been completely in pieces.
Today I'll continue to:
- Connect the wires inside head light.
- Connect the wires for rear lights under the seat.
- New fuel hose from tank to my VM29 carbs.
- Fill with gasoline and firing her up. Maybe tomorrow? :-)

I'll do the same as before, run it on starter and see if the oil lamp can indicate pressure. It worked fine the other 2 times when it was completely opened. No special preparations except oil in the tank, 3L and the tank is still full after almost a week. I oiled everything in engine when assembling it, cam lube used too.
In worst case let the engine run for 5 seconds to get pressure OK. If not, problem... :-(

Oil pump never opened when the screws were too hard to move. I had no reason to doubt its functionality either when the oil pickup net was intact and always been.
Oil pump was filled with a mix of oil and mineral spirit for cleaning it and remove old sludge.

[KRONUS0100]

its for this reason i always pack an oil pump with vaseline.  petroleum based so it dissolves into oil once warmed up.  creates a lot of suction in a new motor and is less wear and tear when trying to prime a motor before start up..  hope this helps.

[trueblue]

its for this reason i always pack an oil pump with vaseline.  petroleum based so it dissolves into oil once warmed up.  creates a lot of suction in a new motor and is less wear and tear when trying to prime a motor before start up..  hope this helps.

+1

[mario medeiros]

OK so forget about the oil light and forget about the oil pressure gauge ,after a rebuild if you disconect the return oil line to the tank and you use the starter should you not see oil level in the tank drop?and oil coming out of the return line?also has had the rocker cover off the whole time,should i not see oil going all over the place?Thanks

[trueblue]

Your pump needs priming, if it isn't primed it won't pump.  It relies on the oil in the pump to seal it well enough to pull suction.  As mentioned priming with vaseline is the best option because unlike oil it won't drain out of the pump, but it will mix with the oil with no ill effects.

[mario medeiros]

Soooo i should see oil  coming out of the return line using the starter? if i don't it means the pump has lost it's prime? because it did prime it already (with oil).

[PeWe]

I got pressure today, by the electric starter!
It took appr 20 seconds or so. The oil lamp lit and not when stopped pressing the starter. Lit again after a few seconds. Off after a quick run with electric starter.

The oil level in oil tank still rather high.

I have to wait to fill tank with gasoline until I have sorted the electric wirings. Brown/white to head-light wring mess and brown to rear light do not want what I want. Everything else works, despite all years in a barn, or 2 different barns to be correct.

[Don R]

Firidup!

[mario medeiros]

Finally i got a stream of oil coming out of the return line for a few seconds then it stopped? WTF!!!!!!