R80 GS running hot
 

I installed one of the thermometer dip sticks before a 3500 mile trip. I noticed that doing 70mph for more than 20mins would lead to a temp of 125°. I cross checked with a friend's thermometer (different manufacturer) and I get similar readings. The pipes are blue to the first bend. I tried changing the fuel mix in the carbs but with no success. It's back at the manual recommended 3/4 turn out. The only other unusual thing about the bike is the exhaust is loud. It's a Keihan stainless which was added less than 3 years ago. I suspect the previous owner ran a rod through it. :thumbdown:

It get good compression from both cylinders. The bike pulls fine. It needed roughly 1L of oil in the 3500 miles.

Anyone had a similar problem? Ideas appreciated.

I had a R100GS, no oil cooler but a deeper sump, and only saw the temperature off scale after going up the Timmelsjoch and Jaufen passes two up with luggage in June. Nothing like that two up with luggage cruising on the motorway. It had a Laser Produro exhaust and y-piece, which weren't excessively loud. Mine used a little oil, but not quite as much as yours. So I can't suggest a solution, but it does sound like it's running hot

Which year?

I am not sure that you have a problem, the pipes blue on all airheads and the temperature does not sound excessive.

My R80 GS Basic (with oil cooler) heats up to 140 C in normal riding condition in summer. I too like you thought something wrong with it. asked to friends and found out it is normal working temp.

Picture of my oil temperature gauge showing that oil emulsification wouldn't be a problem in this thread from another site:

Cortina 2009

1989.

They are notoriously rubbish...

Not if your bike has a header tank :p

The thermometer dip sticks will probably not show the real oil temperature because they only dip inside the engine oil for a very short distance. The most lenght of the stick inside the engine is in contact with the internal engine air, which is hotter than the oil in the oilsump. So I assume, that the dip stick shows a higher temperature.

Normaly oil temperature above 120°C may become critical (depends on the used oil). The air-cooled engines reach often very high oil temperature - so I use an engine oil with 10W-60 or at least 20W-50 specification, to have some reserve.

I have a similar thermometer dip stick - and I only get nervous when it shows a temperature above 130°C - then I just stop and let it cool down. But I have also reached 140°C without a damage.

An oil-cooler may also be a good investment.

Sounds normal.

I tried a thermometer, and got rid of it. The reading was nonsense. Hot pipes, high oil consumption? Not unusual. Is the oil condition good? 20w50 should stay in good condition without going black and thin. That's the important thing. I've got a cooler and a thermostat. I found that without the thermostat the engine was slow to warm up.

Another entirely normal airhead feature is that after a long ride i can switch the ignition off, leave it for 30 seconds, switch the key on, and it restarts the engine all on its own. The bike has now done almost 100,000 and the engine is still excellent, and almost run in.

A friend and I rode 2 GS's ('94 & '95) through parts of the Taklamakan desert on packed and not so packed sand roads where temperatures got to over 46c.
We had changed the oil to full Castrol synthetic 10w-60 in Urumqi and never had any problems. We were not pushing the engined hard though. They were both fitted with the standard oil cooler.
7 years later and the engines have still not had a re-build and mine is now over 100,000.

Years ago an American said to me, "Oils cheap, engines aint" Never a truer word.... :thumbup1:

Thanks guys, I've fitted an oil cooler and it's dropped 15degrees. That plus the comment about the dip stick thermometer not reading true oil temperature makes me think I'll leave it at that and cope with a little carbon the plugs. Better to ride it than worry about it.

125 deg at 70MPH is fine.
The dipstick thermometer senses temperature only at the end, which is quite a bit lower then the oil-level. You can try to heat it with a lighter...

I have compared a dipstick thermometer with a VDO-thermometer placed at the drain plug and found them to be very equal. The dipstick thermometer is a bit faster.
IMHO a thermometer is a nice thing, and I back off when it reaches 140 deg.

Edit: make sure that the oiltemp is above 100 deg at most trips to remove water (condensation).