do i have to rejet my 425 magnum after installing a AAEN megaphone muffler, UNI airfilter, and a polaris white clutch spring. after puttin on the pipe it feels like it has even less low range and acceleration but i think that mid range and top end might have improved just a bit its hard to tell. is it hard to rejet it?

 

Call Aaen and ask, they will tell you. I have called and asked many jetting questions and they were more than happy to answer all of my questions and gave good recommendations.

 

i called them they said to bring the main jet up from a 140- 145 if i needed too. How can i tell if i need to bring it up a size. It is hard to get the spark plug out so is there any other way to tell? Was there a noticeable difference when anyone else put their pipe on? is it hard to rejet?

 

You really shouldnt have to rejet the topend.Try lowering the needle by raising the clip a notch.I know how hard it is to get to the plug but thats really the only sure way to jet.

 

The easiest way to know if you need to re-jet is when you are running at full throttle, flip the choke on, if it almost dies blubbers, etc. you are too rich, if it runs better, you are too lean. You would probably be ok with the jet you have becuase 1 size doesn't make alot of difference. It will make a slight difference in fuel economy and a little power, but if that is all they told you to go, then you are probably ok. If you do the choke trick and it doesn't affect it, change the jet because you are too lean. Reading a plug is the best method. The jet is easy to change. You have to remove the airbox, take the carb loose from the intake if only enough to turn it enough to get the carb bowl off. Make sure the gas petcock is off and the engine is cool. Ok after you get the bowl off, you will see a hex looking brass thing in the middle of the carb. (looking upside down into the carb) that is the main jet, just unscrew it, put the new one in, put everything back together and see how it does. You may also have to adjust the air screw a little, if it is idling and taking off ok, don't worry about that.

 

so if it almost stalls i don't need to put the jet up a size. If it runs better i can go up one size?

 

The 425 is a lot more complicated to get to the carb.You have to pull the tank,side cover and air box and the jet is the new style round flat type.I went to a K&N 142 jet to be on the safe side and still need to lower my needle but its a pain to get to.But hey its a good excuse to adjust the valves and they set at .006. Hey NC pm me some time and see if we can find a place to get together for a weekend ride.

 

Yeh that is an easy way to tell, not necessarily the best, but it works. If you flip the choke on and it cuts out, runs worse you are ok. If it runs better (picks up speed) then change the jet. Yes ftwflh is right, if the bottom end 1/4 throttle to 3/4 throttle is acting up, you may have to move the clip on the needle, but if it is ok, leave it alone.

 

My fault, I keep thinking they are all as easy to get to as mine.[img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img] Same place round jet. Sorry about the confusion.

 

hey i went wide open down the road and flipped the choke on half nothing happened and full and nothing happened. wjhat does this mean?