Smallest SAFE main jet size (50cc)

[50cc]

Hi, in winter my MPG decreases with up to 10 miles. In summer I get 96 MPG, in snow and ice I get 86-88. Running a #75 mj now and I want to decrease it even more. So what do you recommend as the smallest yet SAFE size for a stock 50cc with a free flow filter? I don't want to run it too lean.

[tdawg92]

In my opinion I would keep #75 in summer since u get 96 mpg. In the winter I'd say try a #70.. Since engine will b at cooler temps in winter u can run it a lol hotter.. Try puttin in a #70 take a long ride with it, then pull plug to see if too lean or not, then go from there.. Just make sure when summer comes around u put the #75 back in so u dont burn up engine... Personally I would never go lower then #70

[tdawg92]

A little hotter*

[millsc]

you need a bigger jet or adust to more rich on the a/f screw in the winter the cold air is more dense.

[prodigit]

that would negate what he is trying to accomplish, namely the same fuel economy.
What you say is true, however, if he likes to go on the edge with his bike, in getting the best fuel economy possible, then enlarging the jet would do the opposite he's trying to achieve,.

[50cc]

Thanks guys, I will just stick to #75 then. I guess higher fuel consumption in winter is a normal thing.