Running a little rich, will this help?

[redroost85]

I just had my ride at the dealership to adjust some motor things and the Honda mechanic pulled my plug and it was pretty black, but he said it was not too bad. I replaced it with a new NGK that is the same number as stock, the mechanic said I could even go one number hotter on the plug if I wanted too.

My question is this, I have been toying with the idea of drilling holes in the airbox lid. Will this help offset some of the richness without having to rejet? Will it be too much/not enough? How big/many should the holes be? My whole thing is that I would rather not have to rejet to offset the richness. Any help/ideas would be appreciated. Thanks guys!:)

[RAPTORAZ]

Drilling holes will definately help your richness problem. The best way to do it would be to drill 2 one inch holes at a time until the richness goes away. Alternatively you could also drill 6 one inch holes and then cover them one at a time with duct tape until your air/fuel ratio is in check. Or you could just rejet. Rejetting takes only 2-3 minutes on a 400EX. All you need is a flat screwdriver(to drain the fuel out of the bowl), a 17mm wrench(to remove the carb bowl cap) and a 6mm socket on a 1/4 ratchet(to remove the main jet).

[OutlawEX]

if i was you id just get it properly jetted,unless u want to drill the holes it will ad an increase in power

[redroost85]

Thanks for all of your help guys. I will commence the drilling immediately....maybe I'll wait till tomorrow. I have had a little too much brew to be using power tools tonight!:devil