Running Lean/Rich?

[MasterM3]

Hey guys,

How can I tell if my bike is running lean or rich? I plan on installing a slip on and then deciding if i need to jet the carbs. How can i tell if the bike is running too lean?

[gsxr400 racer]

ride it for a while with the slip on , then check your plugs , they should have color to them . more than likely you will have to just shim the jet needles up

[MasterM3]

hmm, any instructions on how to check the plugs? sorry for such noob questions

[Krautwagen]

Thats a cold - hot scale, but the same applies for mixture.  If they are darker and look like the 'too cold' range above, you're too rich, drop the needles one notch (raise the clip one notch).  If the look like the 'too hot' range above, do the opposite.

[duane]

The above chart seems very handy, but it's resolution is relatively poor (360x147) Does any one have a similar picture but easier to read?

IMHO, The bible.

Another one that helped me immensely.

When you are evaluating your carbs, remember to think in terms of throttle position, not road speed.

This may help:

Place a piece of tape on the throttle housing. Place another piece of tape on the throttle grip and draw a line (while the throttle is at idle) straight across from one piece of tape to the other. When these two lines are lined up, the engine will be idling. Now open the throttle to full throttle and draw another line directly across from it on the throttle housing. At this point, there should be two lines on the throttle housing, and one on the throttle grip. Now find the half-way point between both of the lines on the throttle housing. Make a mark and this will show when the throttle is at half throttle. Divide the spaces up even again until idle, 1/4, 1/2, 3/4, and full throttle positions are known. These lines will be used to quickly find the exact throttle opening while jetting.