Question: Two Stroke Operating Temperature | Spark Plugs

[Street Ryderz]

I changed from the 72 jet to the 70 jet. It seems to be working fine, but on my last ride after awhile I did get a temp as high as 330 using the laser on the outside. Perhaps I'll go back to the 72 jet and change the needle clip if needed. But the thing is, there are several people telling me that 330 is nothing to worry about. That's the downside to this hobby. There is very little incontrovertible evidence as to what is good and what is bad. Everything seems to be opinions and there are very knowledgeable people who will say completely different things.

This is where comparative research is needed, the part you read from Dragonfly/Jaguar stating 450f comes from the 2 stroke tuners handbook and is correct but he omits the fact that this is the combustion temp not an external reading, when high performance builders do an engine they use egt sensor's and do their first runs on a dyno to fine tune it.
Most of us do not have that at our disposal nor is it easy or cheap to do, so were left to tune by plug reading, ear, and the seat of our pants. Using the knowledge gained by decades of manufacture r and d, dyno time and practical experience we can draw our own conclusions using this data base of fact's. Now if you look at any decent 2 stroke that uses sensors you will never see running temps that high, check it out! An air cooled engine does run a tad hotter than liquid cooled but not that much since lc engines also have to consider the boiling point of the coolant, coolant temps are outside the cylinder/combustion area and are absorbing the heat soak from within, this give a good indicator of what outside/external temps should be seen, a lc engine regardless of being 2 or 4 stroke never see's much over 220f as again that's where power loses start and the risk of boil over is present.
Water boils at 212°F at sea level atmospheric pressure. When mixed 50-50 with glycol, the boiling point increases to around 226°F. So with this in mind temp readings taken externally that exceed this are generally considered not good!

 

[DieselTech]

Another factor to consider is emissivity of the particular object you are taking temp of, also does your temperature gun have adjustable emissivity, aluminum has a emissivity of .1 to .2, polished aluminum has a emissivity of .1 or less. Now dirty aluminum has a emissivity of .4 or greater. These are factors that can greatly throw off temperature readings of a particular said object.

 

[Wrench]

Air cooled engine, so take the temp riding it at 30 mph in the wind and see whatcha got.
The temp will always be higher sitting at idle after a ride, But this will give ya an Idea of temps while your sitting at a typical red light
Red lights usually are no longer than 1 min. 99% of the time the bike is in the wind staying at normal temps

Worse case ya gotta sit a red light for 3 mins.

In the wind simulation - Use a floor fan to simulate going 30 mph but ya can't simulate the load the engine would be under as if you were riding it

 

[Wrench]

These are factors that can greatly throw off temperature readings of a particular said object.

Yes, also the distance ya hold a temp gun away can affect the readout.

 

[yuckfoo]

Air cooled engine, so take the temp riding it at 30 mph in the wind and see whatcha got.
The temp will always be higher sitting at idle after a ride, But this will give ya an Idea of temps while your sitting at a typical red light
Red lights usually are no longer than 1 min. 99% of the time the bike is in the wind staying at normal temps

Worse case ya gotta sit a red light for 3 mins.

In the wind simulation - Use a floor fan to simulate going 30 mph but ya can't simulate the load the engine would be under as if you were riding it

I'm generally hopping off the bike and taking the temp as quickly as I can.

 

[Wrench]

I'm generally hopping of the bike and taking the temp as quickly as I can.

Yeh, your bike seems to have normal temps