Spark plugs and 30+ y/o inline 4s

[WarMullet]

I'm on the fence on this one. Sometimes I run higher octane and sometimes I don't. My CB750 is my daily driver so I'm never letting it sit. If I'm going on a long trip I'll usually just throw in 87 since it's going to get used up anyways. Also that's the gas that most people buy so it's the "freshest" if you can call it that hahahaha. The effects of ethanol aren't big enough to really throw into a tuning debate in my opinion unless you really had a solid source to get ethanol free gas all the time which I'm guessing you don't.

You are correct... I'm in an ass rape dont fart for fear of the EPA emissions zone. I suppose just riching up the mixture is the best bet for a happy bike since they were tuned so damn lean from the factory.

[ContractKiller]

I would recommend not running ethanol if you can get away with it. If you have to run it, provided the carbs still have a factory tune, then yeah, you'll probably want to fatten the mix a little. You could get lucky, though. It's entirely possible the carb settings have been changed and it'll run just fine. I know my bike tolerated it just fine when I stopped at a gad station akd all they had was ethanol, but that was the only time I ran it. Best way to find out if you neednto adjust the mix is drain your tank and throw a gallon of ethanol in it, and take her for a spin. If you don't hear any knocking or pinging you're probably fine. If you happen to have fresh spark plugs in there you can check them, too. Like I said before though, these carbs are not made to run ethanol and it can eventually ruin the rubber components. Just keep that in mind.