82 GS750E ?s I am now scared

[posplayr]

The pressure is actually built by the clearance between the rotating assemblies and the bearings. True the pump provides pressure, but really it is flow. To tight a clearance and you will have a higher pressure and lack of lubrication. To large a clearance and you will have a lower pressure, then the oil film will be too large and knock knock, not good.

Volume of oil passages are also part of the formula, but they have nothing to do with building the pressure in the engine. The passages ensure an adequate volume for lubrication, as part of the overall system design.

The manufacturer provides the specific clearances between the rotating assemblies, maintain those and provide a larger VOLUME pump and all will be good, engine will be happy and last long time.

I do not disagree with any of that ; you have can't get any pressure at the bearings if there is to much resistance restricting the flow. The question really is , "If I change my oil and the pressure increases or equally as well when my oil is cold and the pressure is high, do I have more lubrication as when the pressure was lower? In this context lubrication is "hydrostatic pressure" at the bearing.

The answer is, for a given engine, the pressure at the bearing will always be higher if the gauge pressure is higher. We are not designing an engine, only trying to determine what is happening when there is a viscosity change.

[Super]

Hey gs650mann. Where in East TN are you?

Me and my son both have an 82 750E. Really fun bike. We've had them like 3 years now and no issues. Follow what others have said and go with the Rotella oil. I have somewhere on my computer saved the oil pressure mod. Just a matter of adding some more washers but you have to drop the oil pan. I plan on doing mine this upcoming winter since I'm rotating riding this bike with another one I have. You should be fine with this bike and maybe see about doing the mod, either now or in the future some time.

Enjoy riding it. And yes, that guy at bike night didn't know what he was talking about.

[posplayr]

http://turbo-lab.tamu.edu/proc/turboproc/T1/T1pg39-55.pdf

It is turning out that this topic of oil viscosity v.s. pressure is too complicated to come up with a simple set of conclusion. It is clear that pressure is not the only determinant, and that when switching to a multi grade oil, you can have a pressure drop that is beneficial. That benefit is probably due primarily to increase flow. However to suggest that lubrication is wholly to do with flow and not pressure is a bit of an overstatement as initiated Abramovitz paper.
The statement is describing what happens at the bearing not at at the other parts of the system that must be designed to make sure that the appropriate pressure and flow ranges are attained.

This is a balancing act that much be balanced and I would recommend doing what other people have done that is know to work. If nothing else follow the manufacturer's recommendation

https://books.google.com/books?id=ZWj4eqyS6boC&pg=PA94&lpg=PA94&dq=oil+pressure+change+with+oil+viscosity&source=bl&ots=wqbAkFJj-H&sig=oLPz748HwmKkz9mebV6O5EBLirc&hl=en&sa=X&ei=gYhjVe1jiaiiBNb0gOgK&ved=0CFMQ6AEwCA#v=onepage&q=oil%20pressure%20change%20with%20oil%20viscosity&f=false

Pretty good overview of the basics; don't stray to far from the manufactures recommendations

http://www.motorcyclecruiser.com/tips-tech/beginners-guide-to-oil-how-it-works

[GSXR7ED]

16V Engine Flaw

Hmmmm, I remember during my oil pan removal/replacement it was recommended I do a fix (I'm guessing this pressure fix). I didn't do the fix.

I didn't push my bike too hard but I did however make long trips from Alamogordo to Las Cruses/Roswell hitting 6K+ RPMs for several miles and my "T" handled it well. I have to R2 the valve cover gasket, cam-chain tensioner, and fork seals but other than that...all was well with my bike.

Lots of good info here about the 16v engine with flawed design.

Ed

[Crank]

And here I thought one of the only good things on my bike was the roller bearing crank

If you could see the state of the 750 I was given you would understand.