Well, I picked up an 05 GS500F which had apparently been dropped and the fairings had been removed. I got it cheap, so expected a few problems, and sure enough I found the oil cooler leaked!
I tried the usual fix of new O rings, but that didn't work. I then searched eBay for a used one, but again no luck. The price of a new oil cooler was too prohibitive, so I tried to find out if there is a safe way to remove the oil cooler and pipework once and for all. After all, the fairing had already been removed and the perceived wisdom is that the oil cooler was only needed due to the reduced cooling because of the fairing.
I have searched the web and this website for sources of oil flow diagrams and advice on removing the oil cooler, but to be honest there is a definite lack of information. So, I am putting my experiences on here, in the hope it may be of some help to anyone considering doing likewise.

**The big problem with removing the oil cooler system is that down in the sump area there is a direct oil duct that links an oil path coming down from the rear of the engine and joining an outlet leading to the oil cooler. I initially tried fitting an oil pan / sump from the GS500e and hoped I could dispense with this oil duct - which is built-in to the GS500F oil pan. Unfortunately, after fitting I realised that this duct is pressurised, and the red oil light comes on straight away. Engine off and remove GS500e oil pan!

My solution was to bypass part of the oil  path on the original GS500F oil pan. For this you will have to remove the oil pan ( I had already done this in the course of trying to fit a GS500e one). You may not have to remove your exhaust to remove the sump, but I warn you now it is a devil of a job with the exhaust in place!

Diagram 1 (hopefully) helps to explain the route the oil takes underneath the oil pan en route to the oil cooler. It is necessary to link the oil 'exit' at the rear of the oil pan with the front two oil ports (which originally went straight to the oil cooler).

My solution is this: put two M14 x 1.5 oil drain plugs (15mm long) into the two front oil ports. (note these look similar to the GS500 oil drain plugs but are a larger pitch, you need the 1.5 pitch not the 1.25 pitch of the GS's drain plug!). (Diagram 4) Then, I had to drill a hole from within the oil pan down into the oil duct that runs underneath the oil pan. This hole is drilled near the front of the pan and links the rear oil exit and the front oil passage from the oil filter.
I started with a small 2mm drill bit to make sure I got the position right and then went up to an 8mm bit. You must not drill right through the underside oil duct or you will need a need oil pan!

Diagrams 2 and 3 shows the hole and you can now see that the oil from the front of the engine can now flow to the rear oil exit.

One other thing. And I got this from looking at Hayabusa sites. There is a restrictor located behind the oil filter of the GS500F. It narrows the oil passage and presumably creates more oil pressure for the oil cooler. The Hayabusa sites all say remove this restrictor if you remove the oil cooler. It needs an 8mm hex bit, and it can be a pain to remove. I bought a 1/2inch hex bit to remove mine and it came out no problem. I tried with normal Allen Keys but you cannot get enough leverage.

That's it. Oil cooler gone. Bike starts and runs fine and oil light goes out normally just after you start engine. The 8mm drill bit I used to make a hole down to the underneath oil duct is just right. There are other areas of the oil passageways that look as though they are about 8mm internal diameters, so my guess seems about right.

As I said earlier, I could find no oil flow diagrams anywhere, so I am guessing parts of the oil flow system. Inlets may actually be outlets, but they link up and allow good oil pressure through, as if the oil cooler was still there. No, I have not tested the oil pressure with a gauge, and perhaps some might say I should, but I just offer my experiences as a starting point for anyone else to explore the removal of their oil cooler.

[attachment deleted by admin]

well, 2 choices come to mind...fit up an aftermarket oil/transmission cooler or loop a bypass. meaning using the old oil cooler fittings and lines, trim down the lines to the point you can clamp a splice from one line to another. i dont know if the fittings are steel or what. If yes, trim down the fittings to where they just butt up to eachother while mounted (so it looks like a Dogbone) and braze/gas weld them together. could make it real nice and tig weld the joint.

Nice write up but, i think you over looked one thing, oil coolers on ebay are $60 or less

Hi Tomgus, thanks for your info on removing the oil cooler - very helpful. I am looking at doing the same. Are you able to offer any more advice on the oil pressure restrictor? I can see how drilling the oil duct in the original oil pan off the oil cooled engine would work to allow passage of oil around the sump. And why the oil pressure restrictor might need to be removed following the removal of the oil cooler. But I wonder why transferring the oil pan from the naked bike didn't work. Did you try removing the oil pressure restrictor in combination with the swapped oil pan from naked bike, or did you only try this with the original oil cooled oil pan? I would like to avoid drilling the oil passage if I can avoid it, and would prefer to use a naked oil pan if I can. Any advice greatly appreciated. Apologies if this has been answered, but I'm having trouble finding any answers. Cheers

Quote from: tomgus on April 28, 2014, 11:52:27 AMthe perceived wisdom is that the oil cooler was only needed due to the reduced cooling because of the fairing

I know this doesn't help your situation in any way but the above statement is more wives tale than wisdom, forward motion is what cools an air cooled bike..fairing or no fairing. The oil cooler just showed up at the same time as the fairing, one is not required to have the other.

Quote from: florider on August 02, 2014, 08:15:30 AM
Hi Tomgus, thanks for your info on removing the oil cooler - very helpful. I am looking at doing the same. Are you able to offer any more advice on the oil pressure restrictor? I can see how drilling the oil duct in the original oil pan off the oil cooled engine would work to allow passage of oil around the sump. And why the oil pressure restrictor might need to be removed following the removal of the oil cooler. But I wonder why transferring the oil pan from the naked bike didn't work. Did you try removing the oil pressure restrictor in combination with the swapped oil pan from naked bike, or did you only try this with the original oil cooled oil pan? I would like to avoid drilling the oil passage if I can avoid it, and would prefer to use a naked oil pan if I can. Any advice greatly appreciated. Apologies if this has been answered, but I'm having trouble finding any answers. Cheers

Oil ducts inside the engine are re-designed in the F model, hence the need for an F oil pan on an F bike.