my big red, as decribed in my signature, is running a little rich. im trying to lean it out some because it keeps fouling plugs...especially at lower speeds. i have the lid off the airbox, and a large exhaust leak...both things should make it run leaner correct?? however, its still fouling plugs. it doesent break up or run bad in any way, other than when it blackens the plug out. puts out maybe a little black smoke, but not too excessive. anyway..the jets i pulled from the carb are: main:95 secondary:38. are these the stock jets? it seems to be running rich at idle and all throttle positions. i checked the float valve, and its not leaking, the overflow isnt plugged, and the needle is clean. im running an ngk xx7xx with 93 octane gas
will the idle mix screw affect the mix for low-mid, or only idle??
thanks all..

 

The lid off and exhaust leaks should make it go lean. Idle mixture screw will only effect up to 1/8 to 1/4 throttle.
Could you be burning oil? Hows the compression?

 

here's a few things to try to look into, first..make sure your choke isn't sticking in the closed postion,second..check to make sure the air passage in the frame aren't stopped up with dirt doppers ..yea..i know..sounds funny..but..if the carb isn't getting enough air..it's gonna suck more gas..then air !..lol..last..make sure your float isn't sticking..it it does at times..it's going to pull in more fuel than air...oh..and one more thing..as time goes on..i've run across a prob with the main throat jet needle wearing..call it tappering if you will...when it does..it allows more fuel to be sucked into your carb..causing it to burn rich at a diffrent throttle postion.

 

The needle jet and even the jet needle wore excessively in that vintage carb. Seen it many many times. Try a needle jet set (OEM part). It comes with the needle, needle jet, clip, and retainer. When you get your new one, visually compare the size of the hole new to your old one. You will see how much bigger yours has gotten. They run like a million bucks with the new parts (assuming you don't have other problems).

 

i got one name for ya.. Trikeman. go on over to 3wheelerworldforums.com he will know just about anything you will need to know. mostle hondas-BigRed-110-185 and 250R. I know this cuz he is a good friend of mine. he has had that 250R apart down to the floor and back up so many times. all by hand with no ones help. thats pretty impressive if you ask me.