Bike Seems Thirsty!

I am a big guy at 6ft 2 and not light. Been riding the T-80 a lot lately, some runs up to 14 miles plus around town. I have rode it gently, not much over 35mph most of the time but the machine seems to be a bit thirstier than I expected. Has only done 13,000 miles.

I changed air filter to a small K&N style high flow filter, not too long otherwise it would foul the front mudguard. No apparent fuel leaks and I ride it gently through the gears.

What sort of mileages do you get from a tankful? Anything I can check to see that may cause excess fuel consumption (tyres correctly inflated).

Thanks

fender wrote:I am a big guy at 6ft 2 and not light. Been riding the T-80 a lot lately, some runs up to 14 miles plus around town. I have rode it gently, not much over 35mph most of the time but the machine seems to be a bit thirstier than I expected. Has only done 13,000 miles.

I changed air filter to a small K&N style high flow filter, not too long otherwise it would foul the front mudguard. No apparent fuel leaks and I ride it gently through the gears.

What sort of mileages do you get from a tankful? Anything I can check to see that may cause excess fuel consumption (tyres correctly inflated).

Thanks

Around 120 mpg seems about average (or 130 miles to a tank full, tank holds 5 litres)

I tried my t80s fuel range last week it ran dry at 139 miles from full tank..looks to me that the k&n is the cause of your bikes thirst had one on myself for a time .. made mine over fuel(ran rich) dont think the weight would make that much difference ,i ride two up quite a lot an dont see much change in consumption..hope this helps  

I usually fill mine up approximately every 120 miles - when it gets near the bottom of the red part of the guage.

Most of my riding is either on dual carrriageways (full throttle - approximately 50mph) or 40ish on rural B/C roads.

A worn or partially blocked carb can also cause high fuel consumption. Tiny air holes in the needle guide can become blocked due to corrosion or contamination and cause rich mixture at 1/4 to 3/4 throttle. Or if at some point somebody has poked the main jet with wire to clear a blockage the jet can become enlarged and cause rich mixture.

Suitable replacement main jets can be found here if needed:
http://www.ebay.co.uk/itm/CARB-MAIN-JET-6mm-M6-DELLORTO-PIAGGIO-VESPA-SIZE-85-/161311101525?pt=UK_Motorcycle_Parts&hash=item258ee41255

Ι fill with gasoline at 180 kilometers when has left a few in fuel tank.
But I drive more in town and usually with two people.

Do a check at the vacuum petrol switch, if it has punctured the inner membrane sucks fuel from there straight to the intake.
The exhaust smells of unburned gasoline;
You have correctly set the mixture;
Have you  check the condition of the spark plug ?
http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

Plug condition tells me combustion is as good as you can get.
When you just get into the red on the fuel gauge, how many miles do you normally have left?

That could depend on the calibration of the fuel gauge sender unit, There not all exactly the same, some one will have a better idea than me ,

Admin drgaz wrote:That could depend on the calibration of the fuel gauge sender unit, There not all exactly the same, some one will  have a better idea than me ,

As you say Gaz, gauges vary. best idea is to run down to red & then top up & see how much you can get in. Tank holds 5 litres so if you can get in 4 litres you have 1 litre reserve.
You can calibrate the gauge by putting 2.5 litres into tank when gauge should read 1/2 full, if its higher or lower you can remove the sender unit & bend the float arm so as to get the gauge to read right. Of course you have to replace sender unit each time & wait for gauge to settle.