Topic: Lean the mixture or get hotter plugs...

[gregimotis]

CB750f1


So, my bike carbs were last set up 2000ft lower than I now live which is probably why it runs a little rich and over time (1500miles more or less) fouls plugs.  I can't afford to get the carbs re-balanced just now so...



I could get D7EA's to replace my D8's or I could turn my mixture adjust screws out the same amount on each carb.  All correct so far?

The second question is this:  If I turn all the screws the same amount would my carbs stay balanced, or am I inviting Mr. trouble on the door?

Thirdly, is one quarter turn a good increment to start with?


Thanks in advance, I can read a manual well enough, but I don't really understand this stuff well enough to make good judgment calls

[Hockers Choppers]

What year is your bike? On my 78 f the idle screws are on the bottom of the carb up front of the bowl and you turn the screw OUT to richen. If the screw is in the rear side of the carb is controls air for the idle and you turn In to richen. I'd try raising the clip on the needle ( lower the needle ) to the next notch and lean your idle screws 1/4 turn ( the screws don't do much after 1200+  rpms ). What mains are you running? You might drop them a # or 2 also. What is your altitude now?

[Gordon]

You should be able to get away with only making an adjustment to the idle mixture screws for a 2000 foot change.  And don't worry, the idle mixture screws don't have anything to do with the carb balance, so you won't mess that up. 

[Pinhead]

Look up Hondaman's posts on modding the emulsifier tubes!

[gregimotis]

My screws are to the rear and so I turned them out 1/4.  Will wait a while and check the plugs again.  I'm at seven-thousand feet, but any trip I take drops me to two or three thousand feet right away.

Thanks for the replies.  someday I'll be smart like you guys

[Hockers Choppers]

The air screws are just for the idle. You'll probably have to drop your needle to lean it down. But try what you have first don't do 2 things at once or you won't know which one of the changes helped!