Oil pump pressure HVLP V's HVHP

[GS750]

Hi, reading my manual it says the oil pump on my 1977 GS750 is a high volume, low pressure unit, but it does not give spec of pressure (I've read elsewhere that it is between 2 and 5 PSI)

However it also says that the later TSCC models should be around 43 -78 PSI @ 3000 rpm.


They physically look the same in the manual, I could swear that they are an identical photo.

Some questions:
1. Why is one engine low pressure and the later models are high pressure?

2. Would there be any benefits or likelihood of any engine damage on my 1977 (B) if I was to change the unit to the high pressure unit?

[Steve]

I can't say which one your bike is, but the low-pressure models have roller bearings on the crank, the high-pressure models have automobile-style inserts.

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[focus frenzy]

the pictures in the manual are wrong. totaly differant parts and not interchangable.

[renobruce]

As stated, the 8-valve 750 has a roller bearing crank and is low pressure. The 16-valve 750 has a plain crank and is high pressure. The pumps are different. BUT, the 750s came with oil pump gears that move more volume, which will increase your pressure a bit. So I would say your pressure should be between 3 and 8 psi @3000 rpm's after warm-up. I'm sure someone will chime in with the exact figure.

[Steve]

So I would say your pressure should be between 3 and 8 psi @3000 rpm's after warm-up. I'm sure someone will chime in with the exact figure.

I don't have specs for the 750, but my 650 book calls for 0.1-0.5 kg/cm^2 (1.42-7.11 psi) at 3000 rpm, and my 850 book calls for the same.


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