Standing still

**MikeL** · 22nd October 2003, 14:09

Reading Big Dog's post about lane filtering in order to avoid standing still and overheating (coz of his air/oil cooled Suzuki) has made me wonder about overheating with these bikes. My Honda is water cooled and has a temp guage so I know when it gets hot, but what about the Suzuki? My GSX1200 is also air/oil cooled with a small radiator but no fan or temp guage. How do I know if it's getting too hot? Smell? Strange cracking noises? Molten metal dripping onto the tarmac? Since I've only had it for 2 months I don't know how it behaves in summer heat, crawling along the motorway in 1st gear. Anything to be concerned about?

**Motoracer** · 22nd October 2003, 14:14

Being a naked bike, you should feel the extra heat radiating on your legs/upper body etc... The most obvious symptom I reckon is when the engine just gets so hot that it wants to stall at idle.

**jrandom** · 22nd October 2003, 15:20

Hmmm. Looks like the GSX1200's cooling is similar to the FXR's (a bit bigger, of course

)

Adding a temperature gauge should be pretty straightforward. You'd want to have the probe in the oil flow as it enters the wee radiator up front. I imagine there's a stainless pipe at that point? Is it welded to the radiator or does it have a swaged flow-direction push-together kinda link? Never actually looked at that bit closely so I'm guessing wildly here. There must be an obvious way to do it.

(fx: heads out to carpark to look at FXR's radiator)

**jrandom** · 22nd October 2003, 15:28

Actually, bugger the oil temperature, you really want the cylinder head temperature. I think you can get thermocoupling probes that screw in under the spark plugs.

Time for a googlesession...

**Yarg** · 22nd October 2003, 15:56

I had an Yamaha XJR 1200 (Similar to 1200 Suzuki) and had not heating problems at all. Oil cooler worked ok and big head fins semmed to work fine.

**georgedubyabush** · 22nd October 2003, 20:00

Would over heating trigger the red oil warning light? It used to on our last farm quad (yam 600).

**merv** · 22nd October 2003, 20:21

Air cooled bike engines have been around for years and usually they dissipate enough heat straight off the fins to avoid any hassles with overheating. Watercooleds need the fan when stopped because there is little surface area to dissipate the heat without the air flow through the radiator. The engines aren't working hard when you are in neutral but the watercooled has the heat build up because of that lack of direct dissipation i.e. no fins on the block or head to speak of. They need good water flow and air flow across the radiator.

The air cooled and/or oil cooleds are designed to run with a wider range of temperature and hence you hear that watercooleds are more efficient because they run tighter engine clearance tolerances etc. The old air cooleds just cope with the extremes and aren't as highly tuned as the watercooleds and run sloppier tolerances so they won't seize.

I would say a GSX1200 could sit idling all day with no ill effect.

The oil light usually is checking oil pressure and most engines even at idle should be generating enough pressure to keep the light off. At higher revs they have pressure relief valves to stop the pressure from the pump being too great i.e. they keep the pressure in a fairly narrow range. Heat does thin the oil a bit and might reduce pressure but unless that quad was idling too slow, had a faulty pressure relief valve or had a faulty sender unit I would not expect the light to come on just because the motor got a bit hot.

Besides being able to ring more power out of watercooled engines the other plus is damping of noise making them meet decibel standards easier and better control of emissions.

**Marmoot** · 22nd October 2003, 20:28

A good indication: if it starts to knock when you pull the throttle (if it doesn't do this normally), then it is starting to overheat.

**PZR** · 22nd October 2003, 20:36

Originally posted by MikeL
[ My GSX1200 is also air/oil cooled with a small radiator but no fan or temp guage. How do I know if it's getting too hot? Smell? Strange cracking noises? Molten metal dripping onto the tarmac? Since I've only had it for 2 months I don't know how it behaves in summer heat, crawling along the motorway in 1st gear. Anything to be concerned about?

I did the Salvation Army Fundraiser up thru Queen St last year and my (air/oil cooled ) GPZ got so hot at less than walking speed all the oil on the outside started to burn off. Talk about smoke! Did I start to panic? Damn right I did but it seemed to survive ok.

The manufacturers put millions of dollars into making these things so Joe Public can ride them reasonably successfully and they test them in places that get a lot hotter than NZ ever gets so theoretically you should be fine
But what the hell do I know??

**PZR** · 22nd October 2003, 20:39

Originally posted by Marmoot
if it starts to knock when you pull the throttle

Can you elaborate please Marmoot I do not understand?

**Jackrat** · 22nd October 2003, 20:52

I had a 1340 shovel head Harley that could get a bit hot at the lights in OZ,I could see the heat haze coming off the engine,It would knock a bit,pinking and rattling sound coming from the head.If that old thing could get away with it yours sure can,I wouldn,t worry about it mate.With a tight jap bike like yours you
have nothing to worry about.

**Dave** · 23rd October 2003, 07:25

GSXR's were oil cooled for years and years and could be thrashed to death and then left idling for ages without causing any trouble.
Don't even worry about it.
If there was any risk, the manufacturer would have put warnings, and, or a fan.

**georgedubyabush** · 23rd October 2003, 09:16

Originally posted by merv

Heat does thin the oil a bit and might reduce pressure but unless that quad was idling too slow, had a faulty pressure relief valve or had a faulty sender unit I would not expect the light to come on just because the motor got a bit hot.

That quad was just a bastard. Grunty, but a bastard. Needed a new piston/rebuild within 6 months, and the light would come on under load on really hot days even with the fan hard-wired on. Pulling heavy trailers etc. Didnt like pulling a set of harrows much. Apparantly they had a reputation for overheating but maybe we just got a dud. New 660 is watercooled and seems to be doing the trick though it hasnt got too hot up here yet.

**Coldkiwi** · 23rd October 2003, 11:34

Originally posted by Dave
GSXR's were oil cooled for years and years and could be thrashed to death and then left idling for ages without causing any trouble.
Don't even worry about it.
If there was any risk, the manufacturer would have put warnings, and, or a fan.

Maybe true for japanese manufacturers but thats a bit generous as a blanket statement. By that reasoning, ducatis and MV's would have sidestands that actually worked and didn't tend to tip the bike over in a breath of win! As I'm sure BB wil testify, the presence of an item doesn't mean it'll work or is/isn't needed! (like those silly tubes on ZXR's that aren't ram air at all)