i have a 2000 Honda Foreman es 450 and i just put a uni filter in it and im gonna put a hmf utility exhaust. would i have to rejet it?
If you jet them correctly, they will run fine, but sometimes they are hard to get just right. You just have to keep trying until you get it right. It is true that if you don't jet them correctly, they will run worse than stock. If you don't rejet when you put aftermarket pipes and aftermarket air filters on, you will be running too lean and that can damage your engine. If you decide not to rejet, I wouldn't put the aftermarket pipe and filter on the ATV. Most mechanics don't like to rejet because of the fact that it can be time consuming and a big hassle to get it right.well i heard from a mechanic that specializes in street bikes, dirt bikes, and atvs and he said tht they all run worse when u mess with the jets on them. some people put jet kits on their stuff he he takes the jet kit out and puts the stock one back in. is this true?