Heat is BAD! But sometimes good?


I had another article almost done for this issue when I get a phone call. A friend had 6 exhaust systems and wanted to know if I could ceramic coat them ASAP. He was leaving for the 1st National Hare Scramble of the year and several of these exhaust pipes were for some of the top pro bikes. The exhaust routing on these bikes brought them really close to the rear suspension and were causing overheating and seal problems on the shocks. Not only did the suspension start to fade in a race, but the shock had to be rebuilt on a regular basis. He asked how much difference the ceramic coating would make, and I told him I’d test the ceramic coating myself and give him the results on how it would help in this overheating situation.

By now you are probably thinking what does that have to do with my rigid bike! Well more so than a water cooled dirt bike, an air cooled engine is much more affected by the heat surrounding it. This heat comes from your exhaust system. The cylinders, engine cases, fuel tank, oil tank and electrical are all affected from this heat.

As temperature goes up on the engine, your oil and fuel not only affect the performance, but also the life expectancy of your components. Even you as a rider would enjoy a cooler ride…

So let’s get started on the test. I started with 2 tubes cut into equal lengths. One I left in its raw condition and the other I coated with a black ceramic coating. I prefer black due to its higher 2000f operating heat range. I did a full cure of the coating for 1 hour at 750f degrees. I started with the raw pipe and slipped it over my 1000f degree heat gun and slipped in a reducer to help retain the heat since the pipes were short.

After tweaking with the exhaust, I managed to get the temperature up to 1284f, however frying my heat gun in the process.

It was getting a little old anyway and now I can buy that new variable temperature heat gun I have been wanting. For measuring the temperature I used a meter with the thermocouple setup which also gives reliable readings.

The first tube I tested was the one that was left raw. It was slipped over the end of the heat gun for 1 hour and then tested how much heat was radiating from it at 1/8” away.

The temp was 526f with free air around it.

Next tested was the ceramic coated pipe. The ceramic was applied to the inside of the pipe also. This pipe was left on the heat gun for an hour and the temperature of this tube again measured 1/8” away was only 228f degrees. Almost 300f degrees difference between these 2 tubes!

As you can tell from the results this would make a huge difference on the heat affecting your bike and you as a rider. A cooler running engine will last longer, give better performance and also will give you better gas mileage. The coated exhaust also cools down much faster, allowing you to change your plugs or do some maintenance sooner than an uncoated exhaust system.

People: Brew Dude

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