Oil Coolers, Radiators, and Fins.

Cooling... Uber Important!
Having already struggled to clean out the engine cooling fins, today I decided to take a look at the oil cooler. Cosmetically rough, but no leaks, it has a lot of damage to the tiny fins between the oil tubes. Can we fix it? (Bob the Builder could.)

So how does it work?

In the picture above you can see four horizontal flat tubes, which allow oil to flow in one union and out through the other. These tubes are surrounded by the five rows of zig-zagging fins which carry heat away from the tubes.
These tiny fins are warmed up by the hot oil flowing in the cooler's tubes and then cooled by the air flow of the bike moving forwards. Because the fins are so thin, a massive surface area is achieved within a small space, but they are also very fragile! You can see how bent up they are in the picture. 
They should be straight and perfect V-shapes, but over the years they've taken a beating. A jet wash or garden hose can do this if used too close - so be careful with them.

Can it be fixed?
There are specialists who will open them up and re-core radiators/oil coolers but, being as this isn't leaking, I'll clean it up and try to straighten the fins with a tiny screwdriver and tweezers. 
Motocross and enduro bike radiators often need this treatment because of the amount of abuse they take on the track.

GSX750 Oil Cooler Repair

The fins are aluminium so very soft! It doesn't take much to wreck them. Just work along and open them up gently and eventually you should have a view straight through to the other side. They can be finished off with a tweezers, but you'll never get them back to the perfect "new' look. The metal is stretched from damage and you'll just have to settle for the fact that you now have air flow. Besides, who's going to be getting down to look at your radiator or oil cooler?

A slight improvement, I can now see straight through. I'll keep going until they start to look a little more even.

This is the back. Here you can see the uniform V-pattern. Still need to remove the rest of the dirt and paint. It'll be finished in heatproof satin black.

After a bit more cleaning, it's starting to look a little better. I poured petrol into the cooler and flushed it several times to remove the old dirty oil. After a good going over with the airline, she looked somewhere near ready for paint. 

Don't paint in the damp!
Strewth, chucking it down here this weekend and the paint has started to bloom! Never mind, I'll give it another coat when it's warmer if it looks horrendous. Overall, the old thing came up pretty good. 

Roger, and out. I'm off to clean up the cooler pipes. More soon...