Heat Shielding Experiment

[atomsplitter]

I wanted to see if it was possible to reduce the ferocious heat coming off the back cylinder header hitting my right thigh at stop lights so I decided on an experiment to see if it was possible. I purchased a 1 foot by 6 foot piece of Nomex cloth from Amazon and cut a small piece to wrap the back header pipe outlet above the heat shield. I tucked the excess cloth behind the heat shield and held this scrap on with a SS exhaust wrap tie. I wasn't concerned with the look, just heat dissipation. Took the bike for about 60 miles through urban roads with some highway thrown in to make sure it wouldn't blow off. It stayed put all the way and back to home. Roast levels on the right inner thigh were much much lower, so I'm going to double-up the thickness (plenty of room behind the heat shield) and see if I can get it down to being a nonfactor for foot placement at stops during idle. After I determine total effectiveness (and how many layers it takes) I'll look at high temp adhesives as a method of permanently affixing the material. If I can get the heat down to tolerable on the back pipe then I'll treat all three pipes.

 

[sandcritter]

Funny, been pondering having a seamstress do the same to my pants, maybe sandwich some thin woven glass or somesuch. If make it bilateral, might even look fine (if technical). “Rocket pants.” Small market, but may be on to something!

 

[A1A Rider]

Nomex cloth is fire retardant, not necessarily heat proof.

The fibre starts to decompose somewhere around 370‑430 °C. Above that it chars and loses strength; it doesn’t give you magical insulation. The fabric will still conduct radiant or contact heat straight through to your skin, which is why racing and firefighting gear stacks multiple Nomex layers and air gaps to buy a few extra seconds, not minutes.

So the blunt truth: Nomex keeps a flash fire from turning you into a human torch, but it can’t stop you from getting cooked if you hang around the heat source. Treat it as a delay mechanism, not a heat shield.

 

[Kiwicol]

Wouldn't standard exhaust wrap do the same or a better job? You could easily double (or more) layer it if necessary. To me wrapped exhausts look ugly as, but each to their own as they say.

 

[EskimoPie]

I'm continuously surprised to see how much this bothers people. I've ridden my '21 GT in southern Arizona heat nearly daily and all summer long. I've never felt anything that I'd call uncomfortable or worrying heat on my leg. Don't get me wrong, I'm aware the headers are over there but it's never really bothered me. I ride almost exclusively in blue jeans. I imagine that the GT is better positioning than the R in this regard, but I've read about folks with GT's saying they hate it too.

 

[A1A Rider]

I have a GT and it gets hot in S. Florida. My other bike I can mostly tolerate the heat output, generally. But Rocket is too hot.

PS: I mostly cruise at like 35mph or less (due to traffic) 95% of the time. If you are a highway rider, you might feel totally differently.

PPS: My most specific heat complaint is the hot air blowing from a radiator, I see people in this thread having more problems with the exhaust radiation of heat. For me, it is the radiator hot air cooking my leg. Very similar to my other bike.

 

[Tal]

.....i took the heat shield nearest to me off and cemented exhaust wrap on the inside...just cut it to shape and cemented it in there with exhaust cement...it seems to work cos ive never been bothered with heat on my leg..my bike is a GT.

 

[Pump_Guy]

Well,

I had the same issue when using standard jeans. The heat coming from the engine was unbearable at stop and iddling. That changed when I started using Aramid lined pants. Last year coming to Sturgis and riding in between bikes and people, you have to go very slowly, those pants made a big difference for me.

 

[sandcritter]

.....i took the heat shield nearest to me off and cemented exhaust wrap on the inside...just cut it to shape and cemented it in there with exhaust cement...it seems to work cos ive never been bothered with heat on my leg..my bike is a GT.

What kind of cement worked for you, Tal? Kicked this idea around, too.

 

[Tripps]

I never noticed the heat when it was stock, but wow, with the carpenter package and exhaust, it will really cook you now, even with the wrap. Doesn't get ridden a lot in July and August here in Florida, there's better bikes to take when it's hot. I bought a little heat shield thingy for your calf, I was skeptical, it's only about 6" long, but it actually works really well, I was impressed.