Bike engine temp "?"

[Guest]

With the advent of the warmer weather and experiencing the parking lot that is the Don Valley Parkway yesterday night, the bike was getting a little warm.
The temp guage was up to 100C and I could smell the engine cooking, I did manage to drop off and get moving, but at 50-60km/hr the temp did not come down at all. Once I hit the 401 and could wind it up to 120km/hr the temp gradually began to drop once I hit the colder air down by the lake the temp came down into the range I am more accustomed to seeing.

Now for the question, with an air cooled motor and ambient air temperature, is there a point where the fins will not loose excess heat to the air but maintain a temperature or even keep heat in?

[renobruce]

100 Celsius (212 F) isn't bad at all. My bikes with coolers will run about 190 F in the summer. Most oil thermostats are set at 190.

[Griffin]

I have the American (700cc) post '83 version of your GS750E, bone stock. I've owned it since new, and put over 70,000 miles on it. The engine temp (indicated by the little gauge in the corner, I've no way to know how accurate it is) has always read as follows once the engine is fully warmed up:

ambient temps under 50 F (10 C) - engine temp 160 F (71 C)

ambient temps 50 F - 70 F (10C - 21 C) - engine temp 180 F (82 C)

ambient temps 70 F - 90 F (21 C - 32 C) - engine temp 200 F (93 C)

ambient temps over 100 F (38 C) - engine temp 220 F (105 C)

The highest I've ever seen the engine temps for an extended period of time was an all day ride in 95-110 F temps. The gauge read right around 260 F (127 C) for several hours with no ill effects.

It appears that the thermostat is set to fully open at about 180 F (82 c), and maintain an approach temperature of about 110 - 120F (43 - 49 C). Once temps get near or exceed 100F, the cooler is on the very edge of capacity, but will do ok.


Hope this helps.

[zathros]

My 1983 GS750E got terribly hot one day. I realized that I had put the petcock on prime and got gas in the engine. Thank God I was only on the bike for 15 minutes. I pulled into a garage and had the oil changed. When I got home I changed the oil again and filter ( the gas station of course wouldn't carry a Suzuki oil filter) to make sure all the gas was out.

[Nessism]

Synthethic oil is a good hedge against high heat in an air cooled engine. It does not thin out as much as dino oil and clings to the metal better thus providing better lubrication at high temps.