A buddy of mine has a 1983 Honda Shadow VT750 that gets horrible gas mileage. It's about a 3-4 gallon tank and he can't even get to 100 miles on it.
This can't be normal... And I know he's not heavy on the throttle. So what other factors will cause the gas mileage to be so bad? We just cleaned/rebuilt the carbs and put in new spark plugs. The air filter looks pretty clean.
There's also white smoke coming out of his exhaust, even after he has warmed up.
Any thoughts? I know we need to sync the carbs, but I don't think that could cause it to only get 20 miles to the gallon. And the white smoke makes me think he might have a blown head gasket.