• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

GS 750 oil pressure

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Guest
Hi all
i am having problems with the lubrication on my 1977 GS750B, 8 valve engine, the oil light doesn't go off so i removed the clutch and oil pump, sump and strainer, measured the pump as instructed and found everything to be within spec, changed the filter, new oil, turned the engine over, still the light is on so i removed the oilway plug from behind the barrels and there is no oil there at all.Any ideas where to go from here very much appreciated, the drive to the pump was fine, no signs of wear, just not sure what to look at next.
thanks in anticipation
Andy
 
Have you checked that the oil light feed isn't earthing out or that the switch isn't stuck in the open i.e. earthing position? Every oil pressure issue I've come across on a GS is actually an electrical issue.
 
Agree with checking the electrical system. The sensor switch is a simple metal plunger. Then the engine is off the plunger touches the engine which provides a ground path for the light to turn on. After the engine starts oil flow pushes the plunger off it's seat which interrupts the ground path and the light turns off.
 
Might be the pump has lost prime. When you assembled it, did you do it greasily or bone dry?
I'm amazed the number of bikes that sit for years and start up with oil pressure appearing within a few seconds, so the oil pump on these is fairly good at self-priming, but that also depends on the supply to it being a) unblocked and b)air tight.
Might also be a good idea to drop the sump plate and check the pickup strainer - mine was nearly blocked with old gasket and clutch particles.
 
hampshirehog said:
Have you checked that the oil light feed isn't earthing out or that the switch isn't stuck in the open i.e. earthing position? Every oil pressure issue I've come across on a GS is actually an electrical issue.
Click to expand...
i will take it off and check, thanks
 
i removed the sump and checked the strainer, it was pretty clear but cleaned it aswell
 
Disconnect the oil pressure switch, motor stopped. Does it go off now?
If yes, take the oil switch off, reconnect the wire and push the plunger with the switch body in contact with the case.
The light should go out when you push the plunger in.
If memory serves you can turn the crank by hand with the plugs out and oil should appear in the pressure switch hole.
 
Last edited:
the pump was oiled before re assembly, i have taken the pressure switch off and turning the engine over oil comes out of the hole where the switch was fitted but nothing is coming out of the blanking plug behind the barrels which i thought there would be
 
Yes it does, I turned the engine over after disconnecting the wire with the oilway blank removed from the gallery behind the barrel but no oil came out
 
Is the switch plunger with the disc on the end free to move.
If it can't lift clear of the deck when the oil arrives then the wire remains grounded and the light stays on.
Is the insulator between the plunger and the switch housing still ok?
With the switch off the bike check for no continuity between the wire terminal and the switch housing.
If the plunger is not isolated from the housing the oil light will remain on irrespective of the plunger movement.
 
hi
the plunger was seized solid, a new switch has now sorted the issue, is it ok to start the engine with the cam cover removed to check oil is reaching the top end?
 
Maybe OK to crank the engine for a couple of turns of the cams but I wouldn't go starting the engine. Could make a mess. Take the spark plug caps off.
 
andyp62 said:
hi
the plunger was seized solid, a new switch has now sorted the issue, is it ok to start the engine with the cam cover removed to check oil is reaching the top end?
Click to expand...

Like they guys said, messy. Once the oil is up in the main gallery and putting the light off it's a straight run to the top using the holes for the outer rear headbolts. It's hard to see what could prevent that apart from overuse of liquid gasket. Wouldn't be the first time either :)
 
You must log in or register to reply here.

Similar threads

S
81 Suzuki GS650G - oil pressure light flickering on hard stop - marginal pressure?
Replies
11
Views
290
chuck hahn
chuck hahn
R
77 GS 750 - Need Help!! Smoke From PCV Breather / Running Rough When Hot
Replies
3
Views
102
unfocused
unfocused
Rich82GS750TZ
Leak at oil pressure sensor 16v 750
Replies
9
Views
73
rphillips
R
G
GS 750 Oil pump
Replies
10
Views
456
Guest
G
Zellock
That's a Texas GS450T, y'all
2
Replies
23
Views
286
Rich82GS750TZ
Rich82GS750TZ
Back
Top