750ES oilpumpgears

[Rene EFE]

Same as earlier GSX750 so that I can use these? Breaking a bike atm, and need to figure out what to keep. 

[Cobby]

Do you still have the bodywork for the ES? 

[Rene EFE]

No

[Cobby]

No worries 

[arnout]

On 23-8-2017 at 7:35 PM, Rene EFE said:

Same as earlier GSX750 so that I can use these? Breaking a bike atm, and need to figure out what to keep. 

Nope.. Interestingly the NT and ratio of these later GSX750 oilpump gears is the same as the aircooled 1000 and 1100 engines.. (Perhaps the oilpump has a greater volume than on earlier 750/1000/1100 engines?)

[Gammaboy]

7 hours ago, arnout said:

Nope.. Interestingly the NT and ratio of these later GSX750 oilpump gears is the same as the aircooled 1000 and 1100 engines.. (Perhaps the oilpump has a greater volume than on earlier 750/1000/1100 engines?)

What's the primary gear ratio?

Isn't the ratio of the GSX750 oil pump gears to compensate for the different primary drive ratio? The plain bearings just need more pressure, achieved by restricting the flow via the plain bearings.

Edited August 25, 2017 by Gammaboy

[Reinhoud]

On 24/08/2017 at 3:35 AM, Rene EFE said:

Same as earlier GSX750 so that I can use these? Breaking a bike atm, and need to figure out what to keep. 

What to keep?

 

Everything for a while.... From experience, you find a purpose for things straight after you sold it...

[arnout]

Oops.. Failed to keep track of this topic..

On ‎25‎-‎8‎-‎2017 at 3:56 AM, Gammaboy said:

What's the primary gear ratio?

Prim. gear ratio GSX750ES/EF/popup is 1: 1.896 

Oil pump reduction ratio is 1.840 (91/48 x 33/34) which seems odd as this shows the oil pump is spinning slower on this plain bearing crank engine than it is on the roller bearing GSX1100 and GS1000..

On ‎25‎-‎8‎-‎2017 at 3:56 AM, Gammaboy said:

Isn't the ratio of the GSX750 oil pump gears to compensate for the different primary drive ratio? The plain bearings just need more pressure, achieved by restricting the flow via the plain bearings.

Yup, as far as the GSX1100 ('80-'86) vs earlier GSX750 ('80-'82)  are concerned,  that's what I've always assumed and that's what the oil pump reduction ratio numbers seem to confirm. However the bike in question here is the later GSX750 ('83-'87) that has a totally different engine from the earlier 750. Still, both have a plain bearing cranks and both have similar oil pressure specs (3 - 5.5 kg/cm3 @3000tpm). How this similar oil pressure is achieved despite the higher pump oil redution ratio, I dont know. Perhaps the oil pump on the later bike has a greater volume?  (different part.no's suggest different oil pumps between earlier and later 750).

What of course stands out from looking at all the spec though is the massive difference in oil pressure between the roller bearing and plain bearing engines (GSX1100/GS1000/GS750 0.1 - 0.5 kg/cm3 !). Like you suggest I suppose the reason for this is that most of the pressure is "lost" via oilways to the roller bearings that offer little resistance due to their open structure compared to flow restrictive plain bearings.

As a result the similarly  constructed cams shafts on all of these engines have to make do with far less oil pressure on the roller bearing engines and so -I guess- worse lubrication. This is of course where the refitting/swapping of the GS/GSX750 (not: ES/EF/pu) oil pump gears onto the 1100  comes in. I guess though that restricting the oil flow to the roller bearings would have a greater effect in upping the oil pressure in order to achieve better camshaft lubrication.

Nice pic to offset the long text

 

[Nick_C_Hotrods]

On 8/23/2017 at 8:11 PM, Cobby said:

Do you still have the bodywork for the ES? 

I got some if your still looking