Cold Weather Carb Adjustment Recommendations?

After running all summer, and covering many thousands of miles without issue, my bike seems to be running somewhat rough. It did sit unused for a couple weeks at one stage, but I wouldn't think that would be enough time make it run wonky. At least it hasn't been before, though i guess some bad gas could have gummed things up.

Anyway, to my nose it's running rich and it definitely isn't pulling strong. It runs, but solid acceleration yields sluggish pull and a throaty/sick sounding note. And nothing changed w/ a new tank of gas and 75 miles.

I'm up in Maine, any possible cold weather Carb adjustments that I should make to try to remedy?

1075 4-1 Pods
125 mains and
20 pilots
Slide clip to #4 down
Screws 2 1/4 out

Any help appreciated as I'm a dunce w/ carbs.

Assuming it's jetted right, I don't think you need special adjustments for cold weather, except you may have to run with the choke on longer when you first start it up. Sounds more like something got plugged up with gunk. You might try running seafoam in the gas for a while. Also: do you have inline fuel filters? If yes, change them. If not, install them or you will have endless misery with carburetor problems.

Strizzzo wrote:

Anyway, to my nose it's running rich and it definitely isn't pulling strong. It runs, but solid acceleration yields sluggish pull and a throaty/sick sounding note.

Probably should check coils/plugs to make sure it isn't electric. Not as likely, but possible.

If it was weather related the bike would exhibit symptoms of being too lean. Colder air is more dense, more molecules of oxygen per cubic foot, and thus more fuel is required. Within reason however, a carburetor will self adjust to this effect. The denser air flow creates a higher pressure differential at the jet and draws more fuel.

Check your air filter and air box, see if a mouse didn't build a nest in there somewhere while the bike sat. It sometimes doesn't take the little @#%@)(s long to set up shop.

Edit: does anyone know what the effect of the winter-blend gasoline is on a carbureted engine? I know they change the formula as the weather gets cold, and the fuel injection on cars can adjust for it, but maybe this is an issue on our carb'ed bikes.

arthur can you come up and teach my course on carb's i couldn't have said it better myself

ArthurGoVroom wrote:

Edit: does anyone know what the effect of the winter-blend gasoline is on a carbureted engine? I know they change the formula as the weather gets cold, and the fuel injection on cars can adjust for it, but maybe this is an issue on our carb'ed bikes.

It basically has less energy in it so gas mileage drops a bit (like 3%) and power drops the same. I think octane is the same (?) but the gas is just a little worse for energy content.

my truck is carburetted, and I noticed that even when the truck is warm in the winter it doesn't run so good until I add some gas line antifreeze to it. I run a little bottle of the alcohol in there all winter, but when I forget to add one I find it runs bad, and doesnt want to start either.

maybe you could try a half a bottle of iso-propyl alcool (for the frenchies out there!) gas line antifreeze with your next tank

I dont know how cold you plan to ride in but I can tell you at 26 degrees, once it starts & warms up its pretty much the same as normal. If you dont have electric gloves & a heated vest you will be miserable in short order too, I know because I didnt. I just did it to say I rode on Christmas eve in Billings Montana {no snow}