Oil pressure R100gs

[Blythe59]

Good afternoon each, well a bit of a conundrum, just changed all the fluids on my 93 gspd, including the oil filter, went for a spin and did around 70 miles then the oil light flickered on! Stopped, checked oil level after a good 10 minutes, spot on, no leaks. Started bike, pressure light out immediately, went a couple of miles light on again! Same procedure, plus I unplugged the pressure switch and put it on and off a few times to clean the contacts. Started up, light out went five miles or so, same thing again. No funny noises from engine, oil level spot on, bike has 36000 miles on it and I’ve done three oil and filter changes.
So I thought hmm filter seals, the new ones supplied by motoworks are black, not the old white ones, took the filter out and just to be sure put a new filter in, new seals and new shim, started fine, light out, got six miles light on stopped bike, waited a minute or two, started bike light out but didn’t get more than a few yards and light on again. Returned home and wrote this.

Last year I replaced the pressure switch as the old one was leaking, but other than that and the recent oil and filter changes done nothing, well tapper clearances, but they don’t count. The only other ting I did this winter was to send off my speedo to Peter Best to have it converted to mph, and it was a bit of a faf getting it back in, so I wondered if I’ve disturbed the wiring to the indicator light, I don’t know really, advice/ suggestions as to what to check next, or what to do greatly appreciated.

Ta much

 

[mikeyboy]

I think the 1st thing to do is get a pressure gauge on it and see what oil pressure it actually has when running.
If indeed the pressure is low you may well do some very expensive damage if you keep running it.

 

[Blythe59]

I think the 1st thing to do is get a pressure gauge on it and see what oil pressure it actually has when running.
If indeed the pressure is low you may well do some very expensive damage if you keep running it.

Thank you Mikey boy, I was hoping you would see my post, would you be able to point me to a suitable pressure gauge, and what would be a good reading. Thank you

 

[mikeyboy]

Something like this would probably do ,

Oil Pressure Gauge Tester Transmission Engine Test Auto Diagnostic Kit 0-140PSI | eBay UK

8x Petrol Engine Cylinder Pressure Tester Car Compression Gauge Test Kit New. 16PCS Diesel Engine Cylinder Pressure Compression Test Tester Kit Car Tool Set. Cylinder Leak Tester Detector Petrol Engine Compression Leakage Leakdown Kit Set.

www.ebay.co.uk

 

[mikeyboy]

The oil pressure relief opens at @60 psi,
On a cold crank start up I’d expect to see over this initially.
Hot engine at idle @30 psi rising to @60 as revs increase.
IIRC the op switch will close and illuminate the lamp under@ 15 psi.
Another thing to look for is the pressure dropping slowly as the engine is switched off.
If the pressure drops to zero instantly there is an issue

 

[Blythe59]

The oil pressure relief opens at @60 psi,
On a cold crank start up I’d expect to see over this initially.
Hot engine at idle @30 psi rising to @60 as revs increase.
IIRC the op switch will close and illuminate the lamp under@ 15 psi.
Another thing to look for is the pressure dropping slowly as the engine is switched off.
If the pressure drops to zero instantly there is an issue

Thank you Mike, ordered one from Amazon, here tomorrow, then the big reveal

 

[Blythe59]

Well, what do you make of this?

Connected up my new oil pressure gauge this morning, plugs out and earthed, cold crank, straight up to 80psi within ten seconds or so, reconnected the pressure switch, went for a quick tootle, about four miles or so, light came on, returned home, connected gauge, fired her up and at an idle of between 800/1000 rpm showing 60psi, rev to 4000 and showing just under 100 psi, so my suspicion is electrical, what are your thoughts!,

Regards
To all

 

[Mad Hatter]

Rig up a t piece so you can connect the pressure sensor and the pressure gauge at the same time then all will become clear

 

[DrFarkoff]

Well, what do you make of this?

Connected up my new oil pressure gauge this morning, plugs out and earthed, cold crank, straight up to 80psi within ten seconds or so, reconnected the pressure switch, went for a quick tootle, about four miles or so, light came on, returned home, connected gauge, fired her up and at an idle of between 800/1000 rpm showing 60psi, rev to 4000 and showing just under 100 psi, so my suspicion is electrical, what are your thoughts!,

Regards
To all

If your gauge is showing 100PSI ?? The PRV should have blown to relieve pressure at about 60 ish PSI

I always worry about the cheaper chinese gear as you have no idea if it has been calibrated??

Does the oil smell like Engine oil???

I might be dropping the sump off to make sure nothing is obstructing the oil pick up Oh and Inspecting for "the Pin"!!!!

 

[Mad Hatter]

Very easy to drop the sump and it will give you peace of mind as the good Dr says

 

[DrFarkoff]

@Blythe59

LINKY ref "The Pin!"

"Possible" front bearing spinning

 

[mikeyboy]

Might be”much ado about nothing,”
You probably don’t have the hard wear to hook up both the gauge and the switch,
At this point don’t worry too much about the accuracy of the readings,
Fasten the gauge where you can see it and go for a ride,see if the pressure drops off?
If the readings seem consistent mebbs concentrate on the wiring/ electrics.
In my experience,if the oil pressure has been low enough to bring the light on,the big end shells are already bolloxed and it would be noisy( knocking)
I’ve found enough front shell dowels in the sump over the years but I personally have never seen a front shell move or spin,the rear shell has no dowel and I’ve never seen one of them move either.

 

[DrFarkoff]

In my experience,if the oil pressure has been low enough to bring the light on,the big end shells are already bolloxed and it would be noisy( knocking)

Yup @mikeyboy , 100% with you there! If the light was on "for real" for a couple of minutes it would be bad

But I am quite concerned at the very high pressure and the PRV not releasing ?

Hence my "thought" about the crank nose bearing possibly moving

 

[mikeyboy]

Yup @mikeyboy , 100% with you there! If the light was on "for real" for a couple of minutes it would be bad

But I am quite concerned at the very high pressure and the PRV not releasing ?

Hence my "thought" about the crank nose bearing possibly moving

My advice if things seem ok are to leave things alone,
Open up a 40 year old engine and before you know you’re into some big expenses.
Once you see you can’t unsee
These things are either right,or not.

 

[DrFarkoff]

Well, what do you make of this?

Connected up my new oil pressure gauge this morning, plugs out and earthed, cold crank, straight up to 80psi within ten seconds or so, reconnected the pressure switch, went for a quick tootle, about four miles or so, light came on, returned home, connected gauge, fired her up and at an idle of between 800/1000 rpm showing 60psi, rev to 4000 and showing just under 100 psi, so my suspicion is electrical, what are your thoughts!,

Regards
To all

Taking a step back after a decent nights sleep! ............. I find the pressure readings quite high and concerning to be honest!!,
Unless you used straight 30W? or had a tin of STP Oil treatment in there?

BUT Why not, just replace the switch again ? If the cable was grounding somewhere ? It would show as soon as you move off or hit a bump etc etc Switch is a cheap option!
If it still does it? You can check the loom or as I have done Rig an external lamp/wire to the switch It is just a ground to complete a circuit!

If it still messes about with a new switch and checking the loom and external lamp?? I would be investigating further! Something is wrong!! The PRV should release at 60 ish PSI, You really should not be seeing 80 or a 100 PSI !

BUT start with a switch !

61311243414 Oil pressure switch? Your local motor factors should be able get you one

 

[Thejoybringer]

Taking a step back after a decent nights sleep! ............. I find the pressure readings quite high and concerning to be honest!!,
Unless you used straight 30W? or had a tin of STP Oil treatment in there?

BUT Why not, just replace the switch again ? If the cable was grounding somewhere ? It would show as soon as you move off or hit a bump etc etc Switch is a cheap option!
If it still does it? You can check the loom or as I have done Rig an external lamp/wire to the switch It is just a ground to complete a circuit!

If it still messes about with a new switch and checking the loom and external lamp?? I would be investigating further! Something is wrong!! The PRV should release at 60 ish PSI, You really should not be seeing 80 or a 100 PSI !

BUT start with a switch !

61311243414 Oil pressure switch? Your local motor factors should be able get you one

View attachment 497639

Replacing the switch with a known serviceable item would also be my first plan of action

 

[DrFarkoff]

Replacing the switch with a known serviceable item would also be my first plan of action

That is the variant that is not so controllable in todays Cheap schit far eastern manufacturing

But 100% you would hope a new one was Good

 

[Thejoybringer]

That is the variant that is not so controllable in todays Cheap schit far eastern manufacturing

But 100% you would hope a new one was Good

Yep, agreed. I would be going down the road of asking a friend with the same bike/engine if they would be happy for me to transpose the switch for the sake of diagnosing the problem A serviceable switch in the first place is required before more expensive avenues are taken.

 

[DrFarkoff]

Yep, agreed. I would be going down the road of asking a friend with the same bike/engine if they would be happy for me to transpose the switch for the sake of diagnosing the problem A serviceable switch in the first place is required before more expensive avenues are taken.

Agreed and after debating it with myself .. I'm quite good at that Usually whether or not I should do something that my wife wanted done 6 months ago

I think I would merely use the old switch as a temporary plug and not run the other engine with it in at all

 

[Blythe59]

Hi all,
Thank you for the thoughts, I’ve ordered a new switch, didn’t understand why one was seven quid and one was a tenner? So ordered the tenner one, I need to drop the sump anyway because as I replaced the sump guard I managed to sear off one of the fasteners!! Don’t know why but I did

I’ll try Mikeyboys suggestion and go for a ride with the gauge connected, but I’m fairly convinced that it’s electrical. But then!,

Regards to all