What Is A "Normal" Cylinder Head Temperature Range?

[J6G1Z]

Does anyone know what cylinder head temperatures that I need to be aware of?

The Trail Tech Vapor gauge that I'm using has two high temperature warning lights. The first one is yellow, to alert you that the bike is running hot. The second is red, to alert you of approaching the melt down range. Right now these LED warning lights are not set to anything & I need to program the warning temperature set points into the unit.

What is considered to be a safe, normal operating, cylinder head temperature range for an air cooled 500cc 4-stroke single?

What temperatures should I input as my alarm points?


Thank you
J.

[WTF304]

That's a very good question I'd like answers to aswell ... i have a vapor trail tech gauge set aswell ... where did you end up putting the temp sensor ? Mine is on one of the bigger head bolts .... wasn't really enough room to use it on the spark plug

[scottly]

That is a good question. I looked at the factory head temp gauge in my '65 Covair Corsa, and it had a range of 200-600 degrees. Can the Vapor display the head temp while riding the bike, or does it only display the warning lights? If it only shows the warnings, I would try setting the first threshold at some low value, like 250, and the 2nd 275 or 300, and see if the warnings come on during normal riding.

[upperb]

I believe the better thing to do would be to buy the sensor and drain plug adapter and monitor the oil temperature, not that of the cylinder head.  Ideal oil temp would be between 215-230 Fahrenheit degrees.

[upperb]

Realized that I didn't really answer the question.  Mea culpa.

Absolute max for many air-cooled aircraft engines is 425 F.  IMO, measuring cylinder head temp is more useful in making jetting/ignition advance adjustments than for monitoring engine operation during day-to-day driving.  Having an oil temperature guage will, IMO, provide much more usable data in monitoring the overall engine operating temperature than stressing over momentary cylinder head temperature spikes which will occur in stop-and-go traffic. 

Use a good motorcycle-specific oil (Motul, Redline, Brad Penn ) with lots of zinc and phosphorus. Keep the oil at the right temp and no worries or need for distraction.  As regards the use of a cylinder head temp guage in making jetting changes, I believe that an air/fuel ratio guage and a wide-band o2 sensor is far more precise.

[WTF304]

Sorry but i fail to see how an air cooled AIRCRAFT engine relates to a motorcycle engine. Air craft's go up in 10's of thousands of feet, and higher up in elevation air quality goes down. Motorcycle engine's maybe a couple hundred feet if that..... alot more air on the ground. I just fail to see the connection is all .... but your probably right, only thing i can think of is what is the melting point for the materials used to make the head. And stay plenty far away from that point lol.

[upperb]

I specified aircraft because that is what I know.  Perhaps that info is of no use.  Sorry.

[WTF304]

It's not useless info ... just hard for me to find the relation to apply that to a motorcycle. ... with all the variables given. Those airplane engines ... are they cast or aluminum?  ... if they are aluminum then i can see that being if not spot on damn close.

[WTF304]

I took a run last night and payed attention to the temp, it didn't go beyond 280 while running the highway. Once she starts getting to 300 and it will at a stand still she runs like she's getting too hot but that could all be from my jetting. Curious to try a colder plug if i could cross it to one and see what temp i get and how it runs. A good combo of sprockets for highway use for me and my area is a 16t front and a 40 rear.