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Secondary Oil Cooler Fabrication

Rather than nickle & dime a post with questions, I thought a few of you might benefit from a lengthy blow-by-blow of how I did it.

Here's the gallery of all the images of the oil cooler projects.

First, I have not measured before & after temps of the oil. I have only increased the oil cooler surface area. I ASSUME the result is cooler oil. I have a Nordskog Performance Products digital oil temperature gauge but I have yet to install it.

Second I'll tell you how I did it, then I'll tell you how I'd do it again.

For the second frontal cooler I used one from a late 90's 1100. It is the same as the one found on the new 1000 and I mounted it in the same area. For fittings at the end of the lines I bought a pair of lines from a Katana. After careful scrutiny I decided to take a MAPP gas torch and "sweat" the fittings from the lines. Suzuki brazes (solders) the banjo and flat fittings on the oil lines. They use a high temperature brass-based filler so the hotter MAPP gas is better than plain propane. If you have access to a proper oxy/acetylene torch AND know how to use it I recommend using it. I wish I still had one. The banjo line fitting is a steel-based material. The flat fittings are made of a brass alloy so BE CAREFUL not to damage it with the flame. The metal portion of the line is steel. the flexible rubber hose has no internal metal and will melt quickly & burn.

I then took a combo fitting that has a 1/4" pipe thread (male) on one end and -6 AN fitting (male) on the other. The 1/4" end fits into the banjo/flat fitting and then is brazed with a silver-based (lead free) solder. The -6 AN is used to attach a -6 AN (female) fitting on the correct length of -6 stainless braided/rubber lined hose (SBL).



For the "top end cooler" I took a while to decide where I wanted to & could mount it. I originally wanted to put it behind the battery but the air flow would be very poor and actual cooling would be hard to accomplish. In 1999 in either Motorcyclist or Cycleworld I saw a short article about a guy in Georgia with a GSX-R motor in a steel-tubed frame he bought in the UK. It had a top-end cooler very similar to mine mounted under the passenger seat area (he had a 916/996 tail).

The part I remembered most was the "Back Check Valve" it mentioned. Without a BCV the oil in the cooler & the lines would drain back into the main galley (bottom end) and on start-up the cams would not be getting needed oil. That would be bad. So I rang Earl's (in Indianapolis) and they had one in a -8 AN size. So I bought it.
Now the fittings on the "Y" shaped line from the main galley are the same on all oil cooled Suzuki motors...GSX-R, Katana, Bandit...they are all interchangable so find a donor for the project rather than using the only one in the room. This act of insurance came in handy when the shop Dyno-tuning my carbs broke one of the fittings when putting the carbs on after changing the jets. I dropped off the stock "Y" line to get the jetting done and repaired the broken fitting on my own time. There are three ends to this line, I will call them "the bottom" and "the valve ends" (two of the valve ends).

For this cooler I used all the left over steel lines from the front cooler and from the "Y" line. Also had one line with two banjos for the TLS cooler. Using a 1/4"-clamping block (go to a bicycle shop and ask for a "Park Tool Axle Vise") & the torch I was able to heat & bend the tubing to the needed shapes. The tubing has to be bent to pass between the carbs and from the bottom end rearward. A bucket of water & patience is needed. Once tubing is bent it is time for the TLS line. The banjos are steel again but are "male" and simply clamped by the rubber line. A little heat on the clamp & the banjo and they separate easily.
A hose clamp & decorative faux AN nut fits on each of the TLS banjos, each of the valve end lines and on the bottom end line. A true -8 AN fitting is needed for the ends that attach to the BCV & the "T" splitter (for each of the valve lines). These are attached to -8 stainless braided/rubber-lined hose.

Things I would do differently.
1= Instead of sweating the lines out of the fittings for the front cooler. I would sweat the rubber crimped ends off the steel line to use the hose-clamp style fittings. This would save hassle, time & money. It really helped save a few $$ on the rear cooler. It would also allow me to have used larger -8 fittings & SBL.

2= Maybe get a 94 750 main cooler, the larger curved type. It could bolt on with less effort, but with my luck I'd have to fabricate something.

I got my braided hose & fittings at my local Aeroquip dealer but you can also get them from Earl's USA or Earl's UK .

I got my lines and coolers on ebay from various auctions. You could just go to the local bone yard and see what you can find.

If someone needs a close-up of something I can take a image & get it posted. If you have a question, and I'm sure someone will, I'll try to get it answered.

56 Posts
Re: Secondary Oil Cooler Fabrication

you answered alot of my questions, and gave me a few ideas to ponder over too...
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