Oil issue? Pump?

[Pflieger 77]

I have a '77 GS750 and I am working through a revive after sitting in someones shed for years. I have her running and have worked out most of the minor kinks. I notice when i turn it on that the red "Oil P" light stays on despite a proper level of oil in the case. I have disassembled and checked the oil pressure sensor and all seems to operating smoothly but there is very little oil in the sensor housing. I checked the oil filter and barely any oil there.

I am not aware of an oil pump on the bike but please enlighten me if I need to find one. I have dropped the oil pan and there is nothing clogged in the screen and the bottom end of the engine is in really good condition considering the age of the machine.

I have looked up oil pumps for the bike online and can't get a good image depicting it's location. Any help?

KP

[tkent02]

It's on the right side, behind the clutch, driven by the cluth gears.

Odd for one to quit pumping......

[Nessism]

The pump is virtually foolproof. Most likely a problem with the light.

[tkent02]

Likely, but it could also be something blocking an oil passage.

[sedelen]

Oil pressure switch works on the principal that when engine is pumping oil it pushes up on the plunger opening the electrical circuit to the light turning it off. You can check your light by removing the connection to the sensor and it should go out. Grounding it to the engine case should turn it back on. I had one fail on my GS1100, but it was an intermittent problem where it was a matter of it not going off, but sometimes failing to ground keeping the light off.

Page 150 in this service manual.

http://www.mtsac.edu/~cliff/storage/gs/GS750_Service_Manual_early8valve.pdf

You'll also find references on page 29, and oil pump pressure test on 73.

Also, make sure you have enough oil, check the bike on the centerstand and look through the sight glass.
I have also seen one problem like this where a guy installed his oil filter backwards (it's true!).

Oil pressure switch $15.80 @ Boulevard Suzuki, item 36.

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=94632&category=Motorcycles&make=SUZUKI&year=1977&fveh=2133

[Missile99]

Definitely check the few things sedelen mentions. It is most likely the sending unit because of the near-foolproof pump design and considering how clean you say it looked inside. I had the same problem. I was trying to figure out the flow of oil in this thread along with solving my pressure light problem.

http://www.thegsresources.com/_forum/showthread.php?t=193010

I ended up disconnecting the old sending unit and not worrying about it. I bought a gauge from Renobruce to see the working pressure. Problem solved.
Good luck.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Pflieger77,

Here's some supporting documentation for all the other maintenance you'll have to do. It's your "mega-welcome".

If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. In the links below you'll find maintenance lists, documentation, wiring diagrams, "how to" guides, vendor links, tips, tricks, and a whole lot of GS goodness. This is your "mega-welcome". Let's get started.

Let me dump a TON of information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please Click Here For Your Mega-Welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Pflieger 77]

Thx everyone... I have been busy with work and other things this week, but I will dive back into it this weekend and see if I can work through all of the things you have suggested. I appreciate the responses and will let you know.