Topic: Oil not circulating

[74CB750Chopper]

I have a 1976 CB750K on my chopper. I was hit by a semi in June '11 and it has been sitting until February 12' The first thing I did was change the oil because it had been sitting. When I run it up the oil tank overflows after a couple of minutes. The engine seems to be running fine but my oil doesn't seem to be circulating. It is pumping into the tank but oil isn't being pulled out or at least not at the volume it is coming in. I have taken out about a quart and a half of oil just to make sure  Didn't have too much and it i still doing it. I am afraid to run my engine because I am afraid that the engine probably isn't very well lubricated. If anyone has any ideas please let me know. Also the new oil is filthy. I have been talking to some of my work buddies trying to find a simple solution(we are all helicopter mechanics) before I take the whole thing apart and inspect it. Any advice or tips are greatly appreciated!

[wrenchmuch]

Was it on its side for a while? I'm wondering if the pressure side of the pump might need to be primed. I've primed pumps by putting a little pressure into the oil tank with a air line. I put my fingers over the fill hole and put the air chuck between my fingers. I'd pull the plugs and have someone crank it while you put the air in. I wouldn't start it untill you know you have pressure to the crank. You can pull the oil galley plug just above the timing cover to see if you have oil there. The only other way to prime the pump is to remove it and immerse it in oil while turning the gear. Could the oil tank return line be damaged or plugged ?

[bollingball]

Why is the new oil filthy? I would start over. Drain it drop the pan pull the pump clean it prime it. Put every thing back together refill and see what you have. This does not cost much for the peace of mind of knowing where you stand.

                                            Ken

[Bodi]

Probably it wet-sumped while sitting. You drained the tank and refilled it, but maybe with a quantity of oil in the sump? This is a pretty common occurrence. The check valve in the oil pump that's supposed to keep the tank from draining down to the sump leaks a bit - not an issue when ridden regularly but sitting a few months it adds up. The scavenger pump will empty the sump fairly quickly, but if the tank was filled up with oil in the sump, then the tank overflows. Generally, change the oil on a 750 shortly after the bike has been running so the sump is dry - or drain the sump as well.
If you did drain the sump before filling the tank... wohoo you've got a gold mine there! A motor that makes oil!

[74CB750Chopper]

Wow! Thanks guys for all the advice and so quickly, I am losing my mind with this because the weather is perfect and I haven't been able to ride in 8 months! I am going to put your advice to work for me in the morning. I will drain the sump and clean up the pump. I will update you guys on how it works out!

-Derick

Wrenchmuch - It wasn't on its side, I also already checked the oil lines and they are good.

Ken - I am guessing the oil is filthy because with it sitting so long at the shop that stored it the oil broke down and turned to sludge and the new oil has just been dirtied up by that.

Bodi - Thanks for sharing that knowledge with me, I am new to motorcycles all together so I am still getting things figured out.

[bollingball]

I was thing you change the oil the correct way. Check the service manual you drain the sump and tank 

[74CB750Chopper]

Well I dropped the pan, took apart and inspected the pump, put it back together, primed it, changed the filter and oil and she is circulating just fine now. Took a ride around the neighborhood the other day. Now I just need to get new cables made and get my turn signals working correctly and I will be all done. Thanks so much for your help everyone!

[ekpent]

Helicopter Mechanic     Show me which one you worked on before I hop in     Just Kiddin'  enjoy your ride.

[74CB750Chopper]

Don't worry I am a little better with Pavehawks than I am motorcycles I have never had one I worked on go down, knock on wood! This is all just to get it going again, I want to do a rebuild before too long, that will be a fun project, I just dont want to miss the best part of the Las Vegas riding season.