Been getting rely poor gas milage from my, new to me, 97 skandic 500, about 8mpg to be exact or around 95 miles to a tank of fuel. This seems rely poor for a 500 fan cooled. Anyone else with a 503 and can comment on their milage. What are some potential causes/fixes.

I am running factory jets 180/170, but most of my riding is in mid-range, so I tried leaning the needle but I get a hestaion, signalling the engine is too lean, so I returned to factory settings and engine feels perfect now but still poor mileage.

My friend has a 380 and gets way better milage, sure I have a little more pep and about 4 mph on top end, but to me it is not worth the extra gas.

Can anyone help?