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D
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Discussion Starter · #1 ·
Hi Guys

I found that my bike overheats when stuck in traffic on a hot summer day. I know thats what oil boilers like mine do, but if theres a way to reduce it, I'd like to do something about it.

I already bought a HEL cooler (Setrab 19 row), but I was thinking, if it would be even better if I added another small oil cooler in the back somewhere? Or is is a bad idea?

Cheers
 

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stick a a fan on it.

And when you say overheats, does it feel too hot, or does the bike shut down?
I never had a problem with mine, even in a hot sydney summer. Mine had 38mm carbs and an 1196 cc big bore.
 

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jamal avatar #1
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any chance you are running lean?

I'm not so sure slapping a fan on there will solve the issue.

If not lean, I'd check the oil pump
 

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Not sure why I see posts from the US about bikes running hot,
Seen quite a few on a US Busa forum too.

I run several Suzuki's, one air, two oil, and two water cooled.
Even in Australia's Summer I can't over heat them.
Did 22 runs at the drags, when no one else wanted to race in the heat,
never got hot enough to be a drama.

Earlier this year it was 110 degrees F and I had no drama in city traffic.


Serious question....
Are US bikes fuelled any different, carbs or ECU to get them past emission tests?
Are they run leaner than AU / EU bikes to make them clean enough for the US ?

Overheating of bikes isn't common in Australia.

How hot is it over there that your overheating?

44.6 C is 112.2 F

 

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jamal avatar #1
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the poster isn't american. hell i don't even know where that tag is from.
 

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0.o i didn't do it
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Tony I think US models are leaned out more for emissions. Seems that way when I have looked up carb settings for my 94 Kat and the lady's gs550. Not sure if that applies to all US models but it does seem to be the pattern.

Sent from Motorcycle.com App
 

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ShamanFighter
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22,340 Posts
turn the air fuel screws to 2 1/4 to 2 1/2
 
G

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US models are set up lean as stock & the ignition is retarded when compared to UK models, if you bike still runs the imissions control crap, bin it & that will help a little

I believe some US models ran a fan as stock but i think that may have been the gsx1100f (katana)
 

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D
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Discussion Starter · #10 ·
Thanks for all your replies. Sorry I havent got back to you before now.
I just bought a thermometer to check how hot it is running, but havent had a chance to try it out. I havent had it shut down on me, only felt it, and also the idle rpms will rise a little.

I live in Copenhagen, Denmark so it is not a US model.

I should probably mention that it is a '92. I run K&N pod filters / aftermarket exhaust system and Mikuni BST 40 with a dyna jet kit (stage 3).

The air fuel screws are set to what the jet kit instruction recomended - dont remember exactly. So I havent considered that to be a possible solution, even though it might.
 

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I havent had it shut down on me, only felt it, and also the idle rpms will rise a little.
This is probably the biggest misconception about any air or air/oil cooled motor. "When I sit in traffic it feels hot, therefore I assume it is overheating".

It is NOT like a liquid cooled radiator that requires airflow to be effective...why radiators always have fans. People assume that if their air cooled bike is not moving, it is not cooling. This is not true. The fact that you feel a lot of heat means that heat is no longer in the engine.

And if you were to measure it, your engine is at a much higher temperature cruising on the highway than it is in traffic, you just don't subjectively feel it since the wind blows all the hot air away. Often the symptom of "overheating" on air cooled (carbureted) motors people report isn't from the engine being too hot, it's radiant heat soaking the carbs and causing the fuel to percolate, resulting in it going lean. What happens when idle goes lean? It speeds up, if really hot enough it can cause a rough/unsteady idle or stalling when you touch the gas. This is an issue on some bikes that subject the carbs to a lot of engine heat, or for extended periods idling. It can easily be cured by slightly fattening up the idle mixture. Try a half turn out on your fuel screws.

Example...a head temp gauge on my little Grom hangs out at about 300*F at an easy cruise. A prolonged WOT pull will push it up to 360-370. Stop and idle in traffic? It rapidly falls down to about 260, even though it feels hotter.

Unless you have modified the engine for considerably more power with higher compression or forced induction, additional cooling measures are unnecessary.
 

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D
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Discussion Starter · #12 ·
This is probably the biggest misconception about any air or air/oil cooled motor. "When I sit in traffic it feels hot, therefore I assume it is overheating".

It is NOT like a liquid cooled radiator that requires airflow to be effective...why radiators always have fans. People assume that if their air cooled bike is not moving, it is not cooling. This is not true. The fact that you feel a lot of heat means that heat is no longer in the engine.

And if you were to measure it, your engine is at a much higher temperature cruising on the highway than it is in traffic, you just don't subjectively feel it since the wind blows all the hot air away. Often the symptom of "overheating" on air cooled (carbureted) motors people report isn't from the engine being too hot, it's radiant heat soaking the carbs and causing the fuel to percolate, resulting in it going lean. What happens when idle goes lean? It speeds up, if really hot enough it can cause a rough/unsteady idle or stalling when you touch the gas. This is an issue on some bikes that subject the carbs to a lot of engine heat, or for extended periods idling. It can easily be cured by slightly fattening up the idle mixture. Try a half turn out on your fuel screws.

Example...a head temp gauge on my little Grom hangs out at about 300*F at an easy cruise. A prolonged WOT pull will push it up to 360-370. Stop and idle in traffic? It rapidly falls down to about 260, even though it feels hotter.

Unless you have modified the engine for considerably more power with higher compression or forced induction, additional cooling measures are unnecessary.
Wow thanks! It makes good sense. No, I havent done any drastic modification to the engine (Besides some yoshi camshaft), its stock - So you are probably right. Thanks again! :D
 
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