GS750 GS650? Oil Pressure

[Guest]

Does anyone know what the oil pressure level should be on a GS750 or GS650? I think all the 750's have the higher volume oil pump gears and maybe the 650's too? What does the manual say should be the operating oil pressure? Does anyone have a manual and can you take a look for me? I'm most concerned with the models that have the oil gallery plug UNDERNEATH the points cover, which is some of the 750's and 650's. Any info would be very helpful. Thanks!

 

[Dave8338]

Does anyone know what the oil pressure level should be on a GS750 or GS650? I think all the 750's have the higher volume oil pump gears and maybe the 650's too? What does the manual say should be the operating oil pressure? Does anyone have a manual and can you take a look for me? I'm most concerned with the models that have the oil gallery plug UNDERNEATH the points cover, which is some of the 750's and 650's. Any info would be very helpful. Thanks!

I'll check tonight and let you know...I hope! :-D

 

[Tarbash 27]

suzukicycles says "Oil pressure: 1.42 psi @ 3,000rpm" for a 2 valve 750. Mine is about 1 psi at idle after fully warmed up, and about 4 psi at around 5,000 rpm, thanks to your gauge. Thats from what i can remember roughly. My guesstimates might be a little off.

 

[wharrah]

suzukicycles says "Oil pressure: 1.42 psi @ 3,000rpm" for a 2 valve 750. Mine is about 1 psi at idle after fully warmed up, and about 4 psi at around 5,000 rpm, thanks to your gauge. Thats from what i can remember roughly. My guesstimates might be a little off.

Does your gauge "peg' past the 15psi indication and stay there for any length of time? If it has ever done that, did it come back down ok, with no damage to the gauge?

I'd be interested in knowing if the indications for anyone with a 30psi gauge are in a similar range too. I'm nosy. :-s

 

[Nessism]

Plain bearing crank motors, like the 650G (shaft model), require quite a bit more oil pressure than a roller bearing motor 650e (chain model). Make sure you are comparing apples to apples.

 

[wharrah]

Plain bearing crank motors, like the 650G (shaft model), require quite a bit more oil pressure than a roller bearing motor 650e (chain model). Make sure you are comparing apples to apples.

I thought that all of the GS series engines except for the 450 all had roller bearings? Is this not true??:shock:

 

[Tarbash 27]

Does your gauge "peg' past the 15psi indication and stay there for any length of time? If it has ever done that, did it come back down ok, with no damage to the gauge?

I'd be interested in knowing if the indications for anyone with a 30psi gauge are in a similar range too. I'm nosy. :-s

When I first start my bike and the oil is cold, i get very high oil pressure. It usually pins it on choke because it revs to about 4,000 rpm. Pressure slowly drops as the oil warms up because it expands. But once the bike is fully warmed up, it goes no where near 15 psi. maybe 6-7 psi at high rpm.

 

[Guest]

Plain bearing crank motors, like the 650G (shaft model), require quite a bit more oil pressure than a roller bearing motor 650e (chain model). Make sure you are comparing apples to apples.

Do you know by how much? what should the pressure be? What's the manual say for the shafty?

 

[Guest]

I just got off the phone with wharrah... he has the 650 with plain berings. His manual states 43-78 psi @ 3,000 rpms. So now the question is: which GS's came with plain bearings?

 

[Hap Call]

I just got off the phone with wharrah... he has the 650 with plain berings. His manual states 43-78 psi @ 3,000 rpms. So now the question is: which GS's came with plain bearings?

All the 16 valve 750 motors have plain bearings, all the 8 valve 750 motors have roller bearings.

Hap:-D

 

[wharrah]

oil pressures for 750s sought

oil pressures for 750s sought

I just got off the phone with wharrah... he has the 650 with plain berings. His manual states 43-78 psi @ 3,000 rpms. So now the question is: which GS's came with plain bearings?

Actually, Bruce and I found that my CLYMER manual for the 1981-1983 GS650 Suzuki FOURS states:

All CHAIN-DRIVE models (GS650) have low-pressure high-output pumps, and run from 1.42-7.11 psi @3,000 rpm.

Then it states:

All SHAFT-DRIVE models (GS650) have high-pressure oil pumps. Normal oil pressure for these is 43-78psi @ 3,000 rpm.

I was totally under the impression all GSs had roller-bearing mains... what a revelation. Now we're wondering if the GS750s are similar to the 650s in this respect.

Anyone know if the oil pressures match these based on bearing type? :? (edit: just saw the post on 8 and 16 valve 750s... wondering if the pressures printed in that bike model's manual match these...)

I'm always learning something here.

 

[Guest]

All the 16 valve 750 motors have plain bearings, all the 8 valve 750 motors have roller bearings.

Hap:-D

So it seems maybe the indicator is whether the oil gallery bolt is above and behind the ignition cover = roller bearing and below the ignition cover = plain bearing?

 

[Nessism]

Simple way to tell is look at the cam caps on the valve cover - round is 8 valve, square is 16.

 

[Dave8338]

WOW...late to the game as usual, but have learned a pile. I was happy to find that the book states 43-78psi on the shaftie, this comes as a pleasent surprise, BRING ON THE REV's....

 

[Hap Call]

It should be noted that the oil pumps are the same for the 16 Valve GS1100 and the 16 Valve GS750. Also, the oil pump gear sets are the same for the 8 valve GS750 and the 16 Valve GS750.

Hap

 

[wharrah]

Where's the 'EASY BUTTON'?

Where's the 'EASY BUTTON'?

Simple way to tell is look at the cam caps on the valve cover - round is 8 valve, square is 16.

Hap and Ness,

While that round-vs-sqare thing is TRUE for how many valves are in an engine, I don't think we can rely on that alone to tell us what kinds of bearings are in each engine displacement/drive configuration.

For instance, here's why I'm confused:

My GS650L (shaft) has an 8-valve engine (round covers) but has PLAIN BEARINGS and HI PRESSURE oil pump... (a major revelation to me to be sure ~ I thought only GS450s had plain bearings... ).

Yet, another GS650, say an 'E' (with a chain), might also have an 8-valve engine (round covers again), but also has ROLLER BEARINGs and a low pressure but high-volume output oil pump (based on my book's info).

Do you see why we're confused?

If I understand you correctly, it seems you have implied that the 750 engine versions with 16-valve engines have plain bearings (high pressure implied) and the 8-valve version have roller bearings (low pressure implied)... we are trying to figure out if this is correct. No mention is made by you of shaft-vs-chain, as my CLYMER points out.

What is perplexing from all this is that what you propose for the 750s are opposite the findings on my 650, or at least not yet quite apples-to-apples. We know that NORMAL operating oil pressure numbers are tied directly to what types of bearings are in a particular engine. We're trying to decode the matrix of "what bikes have what bearings?," puzzle.

My CLYMERS manual (only dealing with the 650 versions, admittedly) states specifically that regardless of anything else, whether the roller or plain bearings are present in the engine is based solely on SHAFT versus CHAIN configuration ALONE. (Maybe that's because there are only 8-valve 650 engines? My book does not mention 16-valve configurations...)

So, the plot thickens.... we can't yet use 8-valve vs 16-valve as a sole indicator of bearing configuration or oil pressures, because obviously the 650 doesn't fit that mold.

... anybody with GS750 manuals out there that can share any more technical info from their manuals about pressures and different drive-train configurations?

Reno and I are trying to decode the 'how large of scale of oil gauge should a particular bike displacement/drive setup have installed'... for the 650s and 750s.... a 15psi gauge CLEARLY does not belong on a GS650L (shaftie) :shock: ... but it would be fine on a GS650E chain bike (if such a bike exists...)

AND (if possible), we'd like to boil it down to whether or not we can make similar bearing-type assumptions based on where the oil gallery port is located. (Now, admittedly this would be the best-possible solution; but we have to prove it first.)

We need to find someone with 750s (with manuals) (one each, shaftie and chain) and see what their manuals say to be sure about bearing type and normal oil pressures.

We can't take what we thought we knew for-granted I guess.

Thanks for the help everyone.

BTW: Life is never easy, is it? Where's the "EASY button" at for this one? :-D

 

[Guest]

It should be noted that the oil pumps are the same for the 16 Valve GS1100 and the 16 Valve GS750.
Hap

How can that be? I have sold a few oil pressure gauges for some 16 valve 1100's and the 0-15 psi gauges work fine. If the pumps are the same, why would a 650 or 750 run at 43-78 psi?

 

[Dave8338]

How can that be? I have sold a few oil pressure gauges for some 16 valve 1100's and the 0-15 psi gauges work fine. If the pumps are the same, why would a 650 or 750 run at 43-78 psi?

Don't know, but I'm sitting looking at the book in front of me (GS 650L) Shaftie and it clearly states that Chain vs. Shaft is the descriptor.

Wharrah...Now that was some great reading. It's been years since I've read that kind of work!!!
You should think about going into the debate scene. That could have been a scene straight out of Sienfeld and would have had all the gear heads in the audience, rolling on the floor!!!!! :>) = (>:

 

[wharrah]

Wharrah...Now that was some great reading. It's been years since I've read that kind of work!!!
You should think about going into the debate scene. That could have been a scene straight out of Sienfeld and would have had all the gear heads in the audience, rolling on the floor!!!!! :>) = (>:

Um..... thanks..... I think.... 8-[

 

[Dave8338]

Um..... thanks..... I think.... 8-[

All of two thumbs up and then some!!!!!