AT Fuel Consumption

[proxima1304]

This is my second @ 98.

The bike is 28,000 km or so claims the former owner.

The bike's original exhaust tube was a FUBAR so he had a local exhaust manufacturer built one mymicking the originals outline.

So I fixed the new one on it.

A few days back and I ran out of gas and filled exactly 22,3 liters. With it I made smth like 304 Istanbul kms yielding an average of 7,23 liters for 100 kms.

Another Turkish AT user here writing in the local AT forum says he has a max consumption of 5,6 liters/100 km. Both observations were made for city -traffic rides.

Could it be the exhaust pipe to blame? What should be the regular benchmark consumption for 100 kms? Explosions in the tube when I release the throttle after 120kmh indicating rich mixture...


Thanks

Kerem Cesmebasi

[1gear1brake]

My first Twin seemed to be a bit thirsty like yours. The problem was a sticky choke cable where the cable goes into the carburetors. Check the condition of the spark plugs and you will probably find that they are black and sooty. If so, clean them with a wire brush (or replace them) and clean the choke cables. Be careful with the plastic screw that holds the cables in the carbs as these are easy to damage and VERY expensive to replace. This should stop the back-firing too.

[BobA]

..Explosions in the tube when I release the throttle after 120kmh indicating rich mixture...


Thanks

Kerem Cesmebasi

This can also be caused by air leaking into the exhaust between the cylinder and silencer, so check all joints are good.

Bike economy is so hard to guage, as there are so many variables in bike and rider. I have always obtained 50mpg or better on all my AT's



Bob

[1gear1brake]

I've just worked out the conversion and 50 miles per gallon (uk gallon rather than us gallon which is smaller) is equivalent to 5.6 litres per 100 km.

[proxima1304]

thanks a lot. Will follow thru ur prescription.

It is EUR 10 per tank of difference mine is guzzling than yours!



Kerem Cesmebasi

[simon c]

I have an average of 6l/100km (more or less).
When riding fully loaded at 140km/h (on the clocks) I get around 7 litres.
It could be less but I'm happy with it.

[proxima1304]

My first Twin seemed to be a bit thirsty like yours. The problem was a sticky choke cable where the cable goes into the carburetors. Check the condition of the spark plugs and you will probably find that they are black and sooty. If so, clean them with a wire brush (or replace them) and clean the choke cables. Be careful with the plastic screw that holds the cables in the carbs as these are easy to damage and VERY expensive to replace. This should stop the back-firing too.

---------------

Ok suppose choke cable is the culprit...shouldnt I be able to tell it from the high idling rounds of the engine...

I mean if by accident I left my choke on for more than it takes to warm up...I always can tell listening to the engine that I left it on. Now I realize with sticky choke you imply smth relativelly less than a full choke rotation on the engine but still shouldnt I be able to identify from the sound????

Will check the plugs
Will seal off tube joint for O2 entry

[aikidimi]

...using K&N air filter, or another similar one, makes the fuel consumption go down, (about half liter pr 100 km) since the bike is "breathing" better, instead of gasping after more fuel...
Maybe some will disagree, but i came to this conclusion after several measurements on my two twins!

Regards
Aikidimi

[proxima1304]

makes sense although mine is already a replaced K&N but the previous owner says it may have to be looked into for cleaning and or replacement...

so the list piles up

plugs
air filter
choke cables
seal off exh. tube connection

[Radio-active]

makes sense although mine is already a replaced K&N but the previous owner says it may have to be looked into for cleaning and or replacement...

so the list piles up

plugs
air filter
choke cables
seal off exh. tube connection

Also.....if its been tampered with!...the Throttle Position Sensor on the R/H side of the (Front Cylinder) Carb can cause poor fuel consumption / backfiring as it alters the timing....just in case you rule out the other 4 on the list....