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-   -   1995 R80GS MPG and points to look for (http://www.horizonsunlimited.com/hubb/bmw-tech/1995-r80gs-mpg-points-look-58137)

Dicky 10 Jul 2011 11:07

1995 R80GS MPG and points to look for
 
Hi Beemer folk,

I'm currently looking at a 1995 R80GS in very tidy nick. Petrol here in Turkey is very expensive therefore MPG is a consideration. Ridden steadily what MPG could I hope to achieve? Also, are there any known weak points I should be looking out for?

Thank you very much.

Cheers,

Dicky

robinhelen 10 Jul 2011 13:38

I have a 94 which returns 45-60 mpg depending on how it is ridden. High revs really sucks the fuel.

Crossing Africa rarely exceeding 50 mph 2 up we regularly got 60+ on good fuel:scooter:


75-80mph and it's down to 50:mchappy:

Cane it and start doing 6k revs a lot and it drops dramatically:funmeteryes:

Donmanolo 10 Jul 2011 14:58

We don't know much about imperial measures down here, but my 1983 R 80 G/S (same engine) gets nearly 20 km/Litre, if I take it very easy (meaning by puttering around the countryside at 80km/h max)

Anywhere near a town that drops quite a lot. in any kind of stop start traffic it can easily go down to around 16.5 km/L.

My average is actually somewhere between both figures, usually 2 up, on long journeys and not going too slowly. Usually this means hitting reserve after around 280 km, with my 19L tank

dc lindberg 11 Jul 2011 09:10

The 800cc version is the most thirsty of all the air-cooled beemer models...

There are claims that their 800cc engine use about 0.45-0.5L/10km, but to faire... I still have to see an 800cc use that little gas...

My R80 1984 used more than 0.8L/10km when I bought it from the police. The best mileage that I have managed to get out of it is 0.57L/10km. When I did get this mileage I had 44/40 highflow valves, lowered the heads by about 0.8mm (=> about 10.3:1 compression ratio), dual ignition.

What did make a significant change was the installation of the HPN 5th gear sprocket. It resulted in about 0.02-0.03L/10km less consumption.

Here is the thing.
1000cc will use less fuel in most instances - since it revs less, and need less energy thanks to the far higher torque. The newer like the one you look at have 8.2:1 compression ratio, which allows for less good fuel. The down-side is that lower compression ration will result in higher fuel consumption...

You should anticipate that the 800cc will use anything between 0.5L/10km to 0.7L/10km at 90km/h constant speed on a "autobahn". You should not accept higher milage than 0.6L/10km, but if the bike uses more... it will most likely take a lot of work to find the causes and correct them. I 've spent over one decade (>10 years) trying to figure out why my 800 is so darn thirsty. Bought it in 1991 - I've still searching for the reason/causes...

Remeber that the petrol cools the valves and seats, so should you get the bright idea to install smaller jets... it will be best to carry a spare engine...

Looking at your question and that you do point-out that the petrol cost is an issue, I will have to recommend that you look at water-cooled engines since these usually runs at a far better mileage than the air-cooled.

Changing the bing-carbs to throttle carbs like Dell'Ortos 34, Mikuni 34 or Keihan 34 for the 750-800cc series will result in far better milage. You can expect 0.1L/10km improvement. With tuning it is reasonable to achive up to about 0.15L/10km improvement over the bing-carbs. Side-effect is much better gas-respons, enginebraking and idle. Down-side - quite a bit of work to install... there is a wire-split under the tank... the throttle lift is not large enough (I modified my system and still I get only about 80% lift of the throttle).
K&N air-filter will give about 0.01L/10km improvement over the stock paper airfilter; but,... if you drive in dusty/sandy areas... you ought to only use the paper air-filters(!)...

Dicky 11 Jul 2011 16:25

Thank you for your very much for your replies and Albert for a particularly useful analysis.

I currently have a couple of old Yamaha 600's and one of the newer XT660R's with fuel injection. In light of what has been said I will be staying with the XT660R for distance touring.

Thanks again for taking the time.

Cheers,

Dicky

TurkeyRider 12 Jul 2011 06:32

Quote:

Originally Posted by Dicky (Post 342077)
Hi Beemer folk,

I'm currently looking at a 1995 R80GS in very tidy nick. Petrol here in Turkey is very expensive therefore MPG is a consideration. Ridden steadily what MPG could I hope to achieve? Also, are there any known weak points I should be looking out for?

Thank you very much.

Cheers,

Dicky

Hello David,

I jointly own and run Bike Turkey in Gocek Bike Turkey Home, if you need a good mechanic for the BM, there is a great guy in Fethiye - he does all our BM's - even the new one's.

Robert
robert@bike-turkey.com

dc lindberg 12 Jul 2011 13:39

Hi Dicky,

I really like the old Yamaha XT600. Quite fuel efficient. Good engine power. Does well on longer trips.

The newer XT660 is said to have some irritating down-sides, and to be more thirsty. That could be just bad talk, but I've heard it from all continents and all ages of drivers...

I would choose to stick to the old XT600 and to do the appropriate tune-ups like an oil-cooler, wind-defectors/collectors (for cooling the engine and keeping the driver from too much draught.

However... this is a BMW side, so... I'm way off topic! :D

The beemers are very good bikes. Some modifications and they are excellent. The costs vary from moderate to less comfortable costs... If I recall correctly the XT600 weighs in at around 170kg wereas the all stripped down beemers starts at 220kg - those 50kg is a lot of load once the bike tips over (which bikes do have a nasty tendency of doing...).
My R80 tips the scale at around 270-280kg...


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