Help!!!!!400ex stock
#2
Always do a plug chop and see what color the plug is. Get it warmed up and kill it at speed and stop as soon as you can. When it cools down a little check the plug color.Should be a tan to medium brown color. If it's whitish in color,then it's lean. All depends on whether you're running stock or aftermarket filters along with aftermarket exhausts also.This place has jet kits along with individual jets if needed.HONDA TRX400EX 400EX TRX400X main pilot slow jets kit
#4
Links probably worn out and sticking causing the popping noise if you have it adjusted properly. Sounds like posssibly time for a new chain plus check the sprockets.Plenty of kits available or just replace the chain itself.2003 KFX chain and sprocket kit | eBay