1981 GSX1100 Katana Based Project

[Shin-Ken 1074]

In Summer where I am the temps get up to 40 C and above with humidity in the high 90's so air cooled engines need all the help they can get. Although an oil cooler has now been installed on the DW and that will help the oil, I think a little mod to the oil cooler can help a bit more on those hot humid days. Using a sad and skanky old cooler as a template, have made an aluminium deflector for the lower edge of the cooler as well as leaving a gap between the cooler and deflector to ensure the deflector doesn't rub against the cooler cores. Haven't attached the deflector yet, needs painting first.

Oil cooler 64 by Max Mutarn, on Flickr


Oil cooler 65 by Max Mutarn, on Flickr


Oil cooler 66 by Max Mutarn, on Flickr


Oil cooler 67 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Yes, the heavy OEM steel brace under the front guard has been removed and replaced with a much lighter aluminium fork brace that you can see installed above the guard. The OEM plastic front guard has also been replaced with a lighter carbon guard (with Titanium bolts) and painted to look like an OEM Katana guard as well as lowering the guard position on the forks to allow it to blend in with the 18" front wheel.

Thanks for the tip about the CB1100F front guard and how its design may help direct air flow to the cooler, the GSX1135 EF OEM front guard has a similar design and although I have one of those guards I could use, for the Kat look I have stayed with an OEM copy guard for now.

[Rijko]

Is that the original front fender (with *heavy* u-shaped inside bracket) ?

I know you want to keep the OEM Katana look, but have you considered something like the CB1100F front fender ?
Much lighter, and the scoop should help cooling.

CB1100F front fender.jpg

Larry nvr2old used that on his S, imho looks super.

[Shin-Ken 1074]

But have you test ridden it without any 'deflectors'? As visually blocked as the OEM 1150 cooler appears to be, you may find it still does a completely adequate job of lowering temps. On my 11EZ, the temps went from near 300f to barely over 200, even when I have my winter 'thermostat' (cardboard cover) installed over the OEM 1150 Suzuki cooler.

And I never even considered 'airflow' until 2 minutes ago, when I got on my knees in front of the bike and saw that visually, at least, the fender on the 19" wheel completely blocks the cooler. On my bike at least, I think just getting the oil on a detour out of the crankcase cooled it more than the wind blowing through the cooler.

Just my 2 cents. Or 2 grams?

No, the first test ride with the 1150 cooler was with the deflector fitted. After installing the cooler it looked low and just as you have done, got down and looked at the cooler from the front and got the same result, couldn't see the cooler! I had some concern about the cooler not having direct airflow which is why I made the deflector before heading out on the 120 km test ride.

You could be correct about not needing the deflector, I'll do a test in Summer with and without the deflector to see if there is any difference.

Oil cooler 61 by Max Mutarn, on Flickr


Oil cooler 62 by Max Mutarn, on Flickr

Oil cooler 63 by Max Mutarn, on Flickr

[Rob S.]

As an experiment I have made a deflector from 1mm aluminum sheet and installed it under the cowl to deflect the air flow between the guard and cowl downwards towards the cooler. Did a 120km test ride yesterday and with the deflector angle set at 45 degrees the oil temp was stable at 93.9 Celsius. So far so good.

I'll do a few more test rides and check which angle works best for temperature management and once that is sorted the deflector can be painted.

But have you test ridden it without any 'deflectors'? As visually blocked as the OEM 1150 cooler appears to be, you may find it still does a completely adequate job of lowering temps. On my 11EZ, the temps went from near 300f to barely over 200, even when I have my winter 'thermostat' (cardboard cover) installed over the OEM 1150 Suzuki cooler.

And I never even considered 'airflow' until 2 minutes ago, when I got on my knees in front of the bike and saw that visually, at least, the fender on the 19" wheel completely blocks the cooler. On my bike at least, I think just getting the oil on a detour out of the crankcase cooled it more than the wind blowing through the cooler.

Just my 2 cents. Or 2 grams?

[Shin-Ken 1074]

A few more test rides and things are looking good, the minor oil leaks are now fixed and the engine oil temps are much lower now that a cooler has been fitted. Test riding has shown the oil cooler position and stone guard are crushing the speedo cable on left lock and the cooler looks over sized and a bit industrial. I decided to swap the cooler for the OEM 1150 cooler and delete the stone guard.

Using the OEM 1150 cooler has created an issue regarding the oil cooler position and air flow. The stock 1150 cooler was designed to operate behind a 16" front wheel and the DW is fitted with an 18" front wheel and that 2" variation has reduced the air gap between the front guard and the cowl. The result of this is the lower section of the cooler is now behind the front guard and not in an ideal position for clear air flow as it would be if fitted to a stock 1150.

The 1150 cooler is in a good position to allow full steering lock and clear the brake lines and speedo cable so I'd rather not raise the cooler using longer oil lines and create problems with steering and cable clearance. As an experiment I have made a deflector from 1mm aluminum sheet and installed it under the cowl to deflect the air flow between the guard and cowl downwards towards the cooler. Did a 120km test ride yesterday and with the deflector angle set at 45 degrees the oil temp was stable at 93.9 Celsius. So far so good.

I'll do a few more test rides and check which angle works best for temperature management and once that is sorted the deflector can be painted.

The deflector is attached using the bolts holding the cowl fins so I only need to add the defector weight to the running tally.
Oil cooler 60 by Max Mutarn, on Flickr

Subtract the DIY cooler and screen weight, add the OEM cooler and deflector weight.

Running tally = 183,058 grams.

[Lorenzo]

Me too thinks it's the better option

[Shin-Ken 1074]

What oil viscosity are you using?

10W - 40 mineral oil.

[Lorenzo]

What oil viscosity are you using?

[Shin-Ken 1074]

The test ride on the highway today with the new oil cooler went well and the oil temp gauge stayed steady on 98 Celsius, a bit lower than the 139 Celsius it was showing without the cooler riding on the same road. The next test ride will be around town to see how it goes with stop start traffic and slower speeds.

[Shin-Ken 1074]

Oil cooler and screen installed, test ride tomorrow.


Oil cooler 56 by Max Mutarn, on Flickr


Oilcooler 58 by Max Mutarn, on Flickr


Oil cooler 57 by Max Mutarn, on Flickr

[Shin-Ken 1074]

I put the DIY oil cooler on the scales today and it weighed 689 g compared to the OEM oil cooler at 1,273 g. With the end result being almost half the weight of the OEM cooler it was worth the effort.

Now that the cooler vs cooler weigh in is done, it's time for the rock screen and what that adds to the build. An extra 275 g for the screen bringing the total weight of the DIY cooler and rock screen to 964 grams.

Running tally = 183,020 grams.


Oil cooler 53 by Max Mutarn, on Flickr


Oilcooler 54 by Max Mutarn, on Flickr


Oil cooler 54 by Max Mutarn, on Flickr


oil cooler 55 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Weight, or the lack of is the game plan for the build and it's the numbers that count. Have weighed a stock 1985 GSX1135 EF oil cooler, banjos bolts, lines and mounting bracket for a total of 1,273 grams. It will be interesting to compare the stock cooler weight to the DIY oil cooler for the DW and of course to keep it apples to apples, will weigh it minus the rock screen for the first weigh in.

So much steel in the OEM cooler.
Oil cooler 50 by Max Mutarn, on Flickr


Oil cooler 52 by Max Mutarn, on Flickr

[Shin-Ken 1074]

Got the mounting spacers finished and had a dry run to fit the oil cooler and screen today before the screen is painted. It all fits with a few mm to spare but a win is a win.

Oil cooler 47 by Max Mutarn, on Flickr


Oil cooler 48 by Max Mutarn, on Flickr


Oil cooler 49 by Max Mutarn, on Flickr

[Shin-Ken 1074]

With the frame sanded and the aluminium mesh fitted the next job is prime and paint. The aluminium spacers for the frame and new oil cooler lower bracket have been painted and are now waiting for the screen to be done.


Oil cooler 46 by Max Mutarn, on Flickr