Low oil pressure light coming on when accelerating

[sihi]

Hi guys.
I have again problem with my lovely GS 650 GL . Hope somebody know where is it.Because my knowledge ends near head cylinder. About crank case and gear shift case I know very little.
On the begginning I should write what I did to my bike.
-3 months I was using mineral oil 10-40 ,than sometimes it (when hard accelerating) slipped from 5th to 4th gear.
- Than I changed oil to half synt. 15-40 .When I was emptying oil I exactly measured how much go out (it was about 2,5 L) so I fill in 2,7 + new oil filter (problem with gear slipping is gone). But Oil never stay between marks -F -L in oil window . After few seconds of engine running oil disappear.

Problem #1 is that long time ago even before this oil exchange I noticed that under propeller shaft boot is oil leakage. And now every time I check there is fresh oil.
prob. #2 every time when I hard accelerate from 3th to 4th gear or from 1st to 2nd the low oil pressure light come for 2-4 seconds ON ----- I measured oil pressure with oil pressure gauge and it was within specs. Above 3.0 kg/cm2 (43 psi),J Below 5.5 kg/cm2 (78 psi) at 3 000 r/min

Why the low oil pressure light come on (even only for 2-4 seconds) when hard accelerating ??
What cause oil leakage from proppeler shaft boot ??

PS: sorry for my eng.

 

[Steve]

No need to apologize for your English, it's better than many of the Americans here. :encouragement:

You say the oil does not stay between the F and L marks in the window? Under what conditions? The engine should be STOPPED when checking the oil level and the bike should be on the centerstand. When the engine is running, it will ALWAYS disappear from view in the window.

If your oil level is good, check the wire on the sensor. The sensor is on top of the transmission, directly behind cylinder #3. You should see a single wire attached to it. Check the tightness of the wire clip to the sensor. If it is loose, you might be losing connection, which will turn the oil light ON when you accelerate briskly.

.

 

[fastbysuzuki]

Problem #1 is that long time ago even before this oil exchange I noticed that under propeller shaft boot is oil leakage. And now every time I check there is fresh oil.

Chances are the leak is from number 24 on this link http://www.cmsnl.com/suzuki-gs650gl-1983-d-usa-e03_model16043/partslist/BLCK0043.html#results
Have you checked the secondary drive oil level?

there is a workshop manual here. http://zeus.mtsac.edu/~cliff/storage/gs/GS650GManual.pdf

 

[sihi]

Hi Steve.
When I bought bike 1,5 year ago. So for fist time I changed oil + filter as manual says -> 3.2 L and level was between F-L . Than I stared engine for 1 minute, oil disappeared from window so I filled it again so it stayed between F-L (of course bike was on centerstand). But anyway after one ride it disappeared. and it never show again,even if it stay long time on centerstand. but I still think there is enough oil ,since I measured pressure with gauge and it was alright 70psi at 3000rpm

Also on my bike is oil pressure switch behind signal generator cover

 

[Steve]

Have you checked the secondary drive oil level?

On the 650, there is no separate secondary drive oil. The secondary drive is a compartment off the main crankcase, but is fed by the same oil as the engine. There is no separate fill, but there IS a separate drain for it.

So for fist time I changed oil + filter as manual says -> 3.2 L and level was between F-L . Than I stared engine for 1 minute, oil disappeared from window so I filled it again so it stayed between F-L (of course bike was on centerstand). But anyway after one ride it disappeared.

OK, I am still a little confused here. Was the engine running when you checked the oil in the sight glass? As mentioned in my response to FastBySuzuki, the secondary drive has it's own compartment in the crankcase, but is fed by the main engine oil pump. When you drained and measured your oil, did you also open the second drain and include that oil in your measurement? If not, that might be some of your "missing" oil. When changing the oil, you need to run the engine (maybe a bit more than a minute), then let it sit for a few minutes. Check the level in the glass, add as necessary. After adding oil, I would suggest you run the engine again, then stop it, wait a few minutes and check the level again.

Fresh oil from the driveshaft boot would indicate a leak. It would be very hard to clean out the inside of that boot with it still installed on the bike, so there might be some oil trapped that will just take some time to clear out. If there is, indeed, a leak, you would have to remove the secondary drive to change the seal. The space is rather limited on your bike, I think it would require removing the engine from the frame.

Also on my bike is oil pressure switch behind signal generator cover

Yes, you are correct on that. The idea is still the same, though, check the clip on the sensor to make sure it makes good contact with the sensor.

.

 

[sihi]

I always check oil in glass when the engine is NOT running (as I mentioned after 1 minute run) . That's shame because I did't know there is another drain plug. I found It. But what you mean "When changing the oil, you need to run the engine" I hope you did't meaned -> changing while engine is running

 

[Steve]

No. When changing the oil, you will drain BOTH plugs. When you re-fill with oil, you are filling only the main sump in the crankcase until you start the engine, which will pump oil into the sceondary drive area. When the secondary drive area is filled, anything extra will flow back to the main sump, but the amount that is held there (and is drained by that second plug) will reduce the amount of oil in the main sump, so you need to re-check the sight glass after giving the engine the opportunity to fill the secondary drive area.

.

 

[geol]

As far as the oil pressure idiot light coming on, I broke the plastic cover where the wire attaches to the switch. It crumbled. The connector was on tight but the oil pressure light came on and stayed on unless I pulled in my clutch lever. I figured the switch was being grounded because the bare contact was touching the clutch cable. I took a piece of shrink wrap and covered the contact on the wire end with a little cut on the end so I could slide the contact on and the problem went away.

 

[tom203]

Sounds like the oil seal (see parts fiche #24) has failed letting oil leak to boot.. Why this is causing oil light to flicker seems odd... My understanding is that this is a low 10 psi switch so oil pressure would have to fall way off to trigger it. Recheck wiring on oil switch behind signal generator plate making sure there is no bare wire grounding out somewhere.

http://www.alpha-sports.com/spst/1982 GS650G/46.htm?q=suzuki-parts

 

[fastbysuzuki]

Have you checked the secondary drive oil level?

yes apologies for that, I assumed it was like the 850 never seen a 650 myself in the uk just goes to show you should never assume anything.

 

[Brendan W]

Hi guys.
#2 every time when I hard accelerate from 3th to 4th gear or from 1st to 2nd the low oil pressure light come for 2-4 seconds ON

Does this happen only around the times when you change gear ?
If you left it in 3rd gear and accelerated hard would it come on ?
My 850 had a loose clutch nut that was not enough to make noise but enough to slip off the oil pump drive at times. Particularly when down shifting gear or leaning the bike to the right at stop sign.

 

[sihi]

Hi again.

So I figured it out.

4 days ago I warmed up engine than I unscrewed filler and one drain screw under oil pan and 2nd on the left side of the bike near gearshift indicator. Than I measured old oil it was 1,5 L (I didn't toke off oil filter). After that I filled up with 2,1 L to see oil level in glass between -F , -L. Than I ran engine for about 5-7 min. Oil level in glass of course disappeared so I filled up with 0,7 L to reach again level between -F-L. (I have to notice that before refill I was measuring oil pressure and it was good between 25-68 Psi)

I was missing 1,3 L of oil. Of course oil pressure light stop blinking

Unfortunately leakage from proppeler boot is worst. I am using this bike for driving to job . Every day 63 km . After that I am missing about 70-120mL of oil.
+++ It start a bit leaking from 2nd drain screw which I also consider abnormal because I tightened with 60Nm.

As Steve noted I am slowly pressed to take whole engine out.