Exhaust temps

[Peteortiz11]

Hey all! if I aim an infrared thermometer at my exhaust pipes, what would be considered a normal temp range? Right now Im getting anywhere from 450 to 570 degress.

[Suzukian]

WHen you first start it up, it should be hot, and after a while, with some revs, really really hot.

[eil]

I advise not putting too much stock in exhaust header readings, for two reasons.

Infrared thermometers do poorly on certain surfaces, especially shiny ones. I've also found them to be wildly inaccurate anyway. Whether it's because the laser doesn't point to the same place as the infrared doohickey or because they are hard to aim, or because they are just inherently "loose," I dunno but I basically have never managed to get a stable reading out of them. (Infrared _cameras_ are more generally accurate because you can see what's what, but are way more expensive and suffer the same emissivity issues.)

Maybe unless you are tuning a race engine, exhaust header temperature isn't really a useful thing to know in general. If one header was totally cold while the others warmed up then that might tell you that you have an issue with that one cylinder, but that's a narrow use case and you would likely hear/feel that anyway. A far more _useful_ measurement of whether you have one cylinder "weaker" than the others is how well the carbs are balanced. If the carbs are clean, there are no air leaks, and the valves are properly adjusted, then if the balancing gauge shows that the carbs are balanced, then theoretically each cylinder is doing the same amount of "work" in the engine.

[Peteortiz11]

Suzukian, you're bored I take it.. Thanks

[Suzukian]

I think the only time exhaust temps matter is if you are landing a VTOL Jet (if the surface can take it), or your exhaust is blowing out stuff, like a die grinder does, which usually means you've blown a valve.

[bitzz]

Exhaust gas temp is as good an indication of engine tune as a O2 sensor.
Aiming a Harbour freight infra red gun at the outside of your pipes isn't giving you exhaust gas temps

[joequesmith]

I've never tried what you are doing with an IR gun. I have wet my finger and touched them at idle when first starting and also held a thermocouple to them just for a quick sanity check.

Under load, high enough I was concerned about the coating. Maybe 1200 - 1400F near the engine's exhaust port. Looking at some of the data I have, typically seems to run about 400-450C or 750-850F.

[Grand Rouge]

My IR reader indicates "room temperature" with motorcycle in garage sitting couple of days. Aiming for header pipe at top bend because easy to 'sight". 30 seconds and more after start up choke off, idle and reving to 4,000 or so.....with my freshly totally rebuilt and vac synced and mixture screws properly adjusted carbs, the max temperature difference between hottest to coolest header is less than 10%.

Original black chrome exhaust..