GS750 GS650? Oil Pressure

[wharrah]

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

[renobruce]

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!!!!!

[duaneage]

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?

I would have already bought one of your gauges if I didn't have the high oil pressure. personally I'll take the higher oil pressure even though everyone likes the rollerbearings.

[wharrah]

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

LOL... well, yeah, but do I get "two thumbs up" because Seinfeld would have loved it, or "two thumbs up" because you (and the other gearheads in the audience) actually understood and followed what I was trying to say? 8-[ \\/

[renobruce]

I would have already bought one of your gauges if I didn't have the high oil pressure. personally I'll take the higher oil pressure even though everyone likes the rollerbearings.

I can get them configured any way needed. 0-15, 0-30, 0-60, or 0-100. wharrah and I are working on a set-up for the oil gallery bolt that is underneath the ignition cover. We almost have it worked out, and it looks like it will work and look good!

[wharrah]

I would have already bought one of your gauges if I didn't have the high oil pressure. personally I'll take the higher oil pressure even though everyone likes the rollerbearings.

Well, Duaneage, this thread's for you! We're finding out anyone with ROLLER BEARINGS has LOW PRESSURE, and anyone with PLAIN BEARINGS has HIGH PRESSURE. Bruce can set us "HIGH PRESSURE" guys up with appropriate 100psi gauges, no problem! \\/

We're just trying to get his 'what do you need' matrix written down, based on model of bike.

Stay tuned. If you know what you got already, we think we can fix you up now, or at least pretty soon...

Contact Bruce direct via PM for specifics. Depends on where your gallery port is at, too what fittings you need. We're finalizing the setup for the lower-ones like on my 650. Stay tuned.

[Hap Call]

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

I was only refering to the GS750 series of motors. With the 750 motors, if you have round chrome cam cover ends (8 valve motors produced through 1979), you will have a roller bearing motor. If it has a rectangulare cam end (16 valve,1980 through 1982) or no chrome cam end cover (16 valve 700/750 motor produced 1983 through 1985) then it will have plain bearings.

All GS motors 850cc and larger had roller bearing cranks regardless of the number of valves in the head.

It is my understanding that GS650 chain drive motors had roller bearing cranks and all GS650G shaft drive motors had plain bearing motors.
There were no 16 vlave 650 motors that I'm aware of.

I'm not sure about the smaller displacement bikes like the GS550, the GS500 (two or four cylinder), or any of the twin cylinder bikes.

Hap

[Hap Call]

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?

They both have the same positive displacement oil pump, but the big GS motors had less restriction because the roller bearings do not require high pressure but like lots of flow, while the 750 needed the higher system pressure for the plain bearings. Kind of like pinching off a water hose - same source of water flow but different pressures when you pinch the hose. Look up the Suzuki part number for the pumps and you will find that they are the same - part # 16400-49220

Hap

[renobruce]

They both have the same positive displacement oil pump, but the big GS motors had less restriction because the roller bearings do not require high pressure but like lots of flow, while the 750 needed the higher system pressure for the plain bearings. Kind of like pinching off a water hose - same source of water flow but different pressures when you pinch the hose. Look up the Suzuki part number for the pumps and you will find that they are the same - part # 16400-49220

Hap

Thanks for clarifying, Hap. So I think we are back to: If the oil gallery hole is above and behind the points cover, is a low pressure system with roller bearings. If it is below the points cover, it is a high pressure system with plain bearings. All the pics I have looked at would indicate this.

[renobruce]

They both have the same positive displacement oil pump, but the big GS motors had less restriction because the roller bearings do not require high pressure but like lots of flow, while the 750 needed the higher system pressure for the plain bearings. Kind of like pinching off a water hose - same source of water flow but different pressures when you pinch the hose. Look up the Suzuki part number for the pumps and you will find that they are the same - part # 16400-49220

Hap

And then there is the '83's... the 750E has TWO oil gallery bolts and a different oil pump.. part # 16400-31300, but looks to be a plain bearing crankshaft. The 750T and Katana have the oil gallery underneath and the oil pump you mentioned.

[Hap Call]

And then there is the '83's... the 750E has TWO oil gallery bolts and a different oil pump.. part # 16400-31300, but looks to be a plain bearing crankshaft. The 750T and Katana have the oil gallery underneath and the oil pump you mentioned.

Very good point, the '83 was the second generation of the 750 TSCC engine and shares no parts with the earlier TSCC engine.

Hap

[renobruce]

While we are on the subject, does anyone know what the pressure level is on a roller bearing 750 with the high output gears?