Bonneville America Forums Forums Technical Forums General Tech How hot is too hot?

I was riding home today and ran into a big traffic jam behind an accident. A lot of idle and slow roll forwards. Outside temps were only about 65 so not hot out but the bike heated up above 100 degrees Celsius. Is that normal? How hot is too hot and what should be done to keep the temps down - outside of staying out of traffic jams.

My ba reaches 225 deg f regularly with a 65 deg ambient air temp if Im riding hard or if Im sitting in traffic a good bit.I think your fine.

Put a helmet on it.

Don't forget that a water cooled engine regularly runs at just under 200F. Air cooled engines should be able to handle this. They should be able to handle 212F or 100C easily. Just make sure you use a good quality synthetic oil with the right viscosity. The oil will thin at high temps. I would use a 20W50 over the 10W40 oil for that very reason.

I run 20W50 Amsoil but at 65º F my bike never breaks 200º now when it is really hot out I have had mine up to almost 250ºF on my trip to Fl this summer for instance. It was well over 100ºF out and even at highway speeds it was running about 225º.

When the engine gets too hot it will let you know.



Generally they seize.!!!!

when I run flat out highway in the summer heat mine gets up around 220-230º, when it's 65º out it won't break 200

I gotta get one o' those oil temperature gauges.

Why.....it's winter......yah won't need it......

You might want to invest in some studs for those tires though

I think it's important Keith. I have been on the verge of pulling over to let my bike cool several times and glad I was aware of the heat unless it got any hotter.

makes me wonder what temp I was running when I went to Sturgis in '08... running 2-up at 85-90 mph for some stretches down I-90, didn't have a gauge on then, just used an infrared thermometer on the oil line fittings when I wanted to know, and that wasn't often

a gauge is a small investment when weighed against an over heated motor that's for sure.

Yes, the gauge is a good guide. I do run 20w50 and it sounds like 100/212 is okay. So aside from her seizing up, is 120 the pull over point? That is the red zone on my gauge.

What gauge have you used?

I have had my bike at sustained temps of about 240ºF on very hot days on very long multi-state rides. Bike never showed any signs of distress not pinging or anything. So in my opinion you are probably safe up to at least 250º but I would pull over if my bike ever hit that and let it cool. That being said 99% of the time I run below 120ºF.

If you over heat it will start to missfire abit and run really rough. thats to hot and on the verge of over heating.
either kill it or take off and let the air cool action work. If you kill it setr till you can touch bare handed the exhaust pipe near the head. before you take off again.

slightly before the red zone on the temp gauge.

120 Degrees F? that's almost cold fusion

I did mean 220º and most of the time under 200º

I have seen mine get up to 220F on very hot days (very rare here) while sitting in traffic. Drops back down to 200F when moving.

the only time I got worried about burning it up was stuck on Lazzele Ave in Sturgis (08) and it got up to 240F. I was roasting too. Didn't hurt the bike a bit, I recovered with a cold beer.

Interesting to note that before the BB the engine ran consistantly 20 F cooler across the board.