Engine Cooling in Hot Climes

[Guest]

Recently back from a biz trip to Tucson and Phoenix and noted some older in-line 4 bikes like Suzuki's and Yamaha's riding on city streets with daytime temps of 110 degrees. None had auxillary oil coolers. My bikes get hot in lesser temps and exhibit sluggish running.

How is it possible that these bikes don't overheat in stop and go traffic and what would be the signs if they were?

[salty_monk]

Idle RPMS would increase 200-300rpms & it would be increasingly difficult to shift.

Use decent oil (synthetic is most stable at ultra high temps but I use Rotella 15-40 for what it's worth....). I've had no probs with mine in those sort of temps, stop & go or running decent speed on the freeway.

Dan

[Steve]

My bikes get hot in lesser temps ...

Well, of course they get hot.
Combustion temperatures are about 1700 degrees Fahrenheit.

The aluminum engine parts do a decent job of dissapating that heat to the air around the engine.
Do you have a thermometer on the bike?
What does it read?
Any idea what the recommended max temp is?
No? That's OK, I don't either.

Everybody has a preference and/or opinion as to what the 'ideal' operating temp is. Also, where should that temperature be measured? Should you rely on cylinder head temps or can you go with oil temps? Should the oil be 180 degrees or over 212 to boil off the water? How many (air-cooled) bikes have any kind of temp gauge anyway?

See what I mean? Also, how many bikes are running so close to the 'ragged edge' that another 10 degrees of air temp is going to cause problems? Unless you are running super-lean, you should not have any problems running in any temperatures that are likely to happen.

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[DanTheMan]

Increase speed to the maximum allowable limits........

[chuckycheese]

Hot town, summer in the city!

I've thought about that issue as recently as this afternoon (it's almost 100 degrees today) while I was sitting at one of those intersections where there's about 6 different settings on the lights.

I've never had a problem but I know my bikes get hot....especially the 1100. It's noticeably hotter than the 750 and I notice that even in the winter.

[Nessism]

The topic about the necessity of an oil cooler comes up all the time. Just about every air cooled bike built starting in the mid 80’s has one but our GS’s don’t. Basically, an air cooled engine is a compromise of some sort; too much cooling doesn’t let the oil come up to temperature and too much heat can lead to oil breakdown. My personal opinion is that an oil cooler is a good idea if the air temp is 90F and above. Synthetic oil is also a good idea since it protects better in extreme heat.

[chuckycheese]

The topic about the necessity of an oil cooler comes up all the time. Just about every air cooled bike built starting in the mid 80’s has one but our GS’s don’t. Basically, an air cooled engine is a compromise of some sort; too much cooling doesn’t let the oil come up to temperature and too much heat can lead to oil breakdown. My personal opinion is that an oil cooler is a good idea if the air temp is 90F and above. Synthetic oil is also a good idea since it protects better in extreme heat.

Yeah, the difference in oil performance in hot weather is noticeable. I change mine several times each summer and am going to switch to your Rotella recommendation next time I change it.

[salty_monk]

Rotella was my recommendation... that's a 15-40 dino but it's truck oil so holds up much better than others i've used.

Nessism is Synthetic all the way.

Horses for courses & all that

[Nessism]

Rotella was my recommendation... that's a 15-40 dino but it's truck oil so holds up much better than others i've used.

Nessism is Synthetic all the way.

Horses for courses & all that

Rotella synthetic is 5W-40; it flows well when cold so start up wear should be minimized. Yea, I like synthetic but mostly because I like to waste money on my bike. The regular dino flavor diesel oil is just fine, in fact, I've got a jug waiting for my next oil change.

[Grandpa]

Guys, I had 23 years and a quarter million miles on GS shafties. Four 850's and an 1100GK -- the latter for 9 years and 107,000 miles. The head has never been off that bike, which I sold to TheCafeKid, with 132,000 total miles.

No failures whatsoever due to heat. I don't live in Phoenix, but no one can say the mid Atlantic States are cool in June, July, or August.

No oil cooler on any of my GS shafties. No need for one.

When weather was hot, I changed the oil more often; instead of 2,000-mile interval, I changed it at 1,000 or 1,500 miles. Filter too. I used Rotella Synthetic 5W-40 on the GK the last 2 seasons. Before that, I used Yamalube 20W-40 most of the time.

If you want an oil cooler, fine. Get one and install one. Don't tell me, however, that it's a necessary thing. Nonsense!

[chuckycheese]

Rotella was my recommendation... that's a 15-40 dino but it's truck oil so holds up much better than others i've used.

Nessism is Synthetic all the way.

Horses for courses & all that

Sorry...... based on what you guys said the last time I got 'beat up', I figured I'd better switch to something else!

I was planning on the regular Rotella 15-40 and looked at it today at Walmart. The only reason I didn't buy any is because I was on the big bike (no saddle bags).

[chef1366]

Guys, I had 23 years and a quarter million miles on GS shafties. Four 850's and an 1100GK -- the latter for 9 years and 107,000 miles. The head has never been off that bike, which I sold to TheCafeKid, with 132,000 total miles.

No failures whatsoever due to heat. I don't live in Phoenix, but no one can say the mid Atlantic States are cool in June, July, or August.

No oil cooler on any of my GS shafties. No need for one.

When weather was hot, I changed the oil more often; instead of 2,000-mile interval, I changed it at 1,000 or 1,500 miles. Filter too. I used Rotella Synthetic 5W-40 on the GK the last 2 seasons. Before that, I used Yamalube 20W-40 most of the time.

If you want an oil cooler, fine. Get one and install one. Don't tell me, however, that it's a necessary thing. Nonsense!

Nick, I use an oil cooler. I don't run lean and the bike is tuned well.
I live in an area where daytime temps can reach 115F. The bike gets hot and breaks down the oil. I get more miles out of my oil now that I have one. "Sometimes" they are needed. If I lived in your neck of the woods (which is where I'm from) I would not run one.

[Grandpa]

Nick, I use an oil cooler. I don't run lean and the bike is tuned well.
I live in an area where daytime temps can reach 115F. The bike gets hot and breaks down the oil. I get more miles out of my oil now that I have one. "Sometimes" they are needed. If I lived in your neck of the woods (which is where I'm from) I would not run one.

Understood.

[Steve]

Just some further obsrvations, based on responses:

Increase speed to the maximum allowable limits........

Up to a point, of course. As you go faster, it requires much more fuel to overcome aerodynamic resistance. You will add more heat than the increase in air will remove. A practical limit for this theory might be around 60-65 mph, but that is just a guess.

The topic about the necessity of an oil cooler comes up all the time. Just about every air cooled bike built starting in the mid 80’s has one but our GS’s don’t.

Part of the reason for that is that many of the bikes use air/oil cooling. The oiling system is designed to spray oil directly on the bottom of the piston crown to help cool the piston. This puts more heat into the oil than our bikes, making a cooler more than just a 'nice thing to have'.

Yea, I like synthetic but mostly because I like to waste money on my bike. The regular dino flavor diesel oil is just fine, in fact, I've got a jug waiting for my next oil change.

I use Rotella synthetic on virtually everything I have, too. I was just walking through Wal-Mart tonight, here in Alabama, and was noticing that the price has gone up to $20 for that blue jug that only recently cost about $18.

... When weather was hot, I changed the oil more often; instead of 2,000-mile interval, I changed it at 1,000 or 1,500 miles. ...

I wish I had the money to be able to do that.
My oil-change schedule would make many of you cringe, but it has served me well, even though I don't have quite the mileage history of our esteemed 'elder' (former GS owner), Grandpa. My riding history has a hole in the middle of it. I rode from 1976 to 1983, then from 2000 to the present, so my odometer totals are a bit lacking.
'76 KZ400 - 22,000 miles
'77 KZ650 - 38,000 miles
'79 KZ1300 - 76,000 miles
'84 ZN1300 Voyager - 55,000 miles
'00 GL1500 Wing - 44,000 miles

This does not even count the 18,000 or so that my wife has put on her bikes over the years or the 20,000+ that my older son has put on his bikes.

I get more miles out of my oil now that I have one.

How do you know?
Do you just feel better about it, or do you actually submit your oil for analysis?
Mind you, I'm not criticizing, just curious.


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[chef1366]

I send it to Ed.
My bike shifts hard when the oil is spent.