Hey guys, I just added an AAEN pipe and jetted it with a dial-a-jet, I have a clutch kit, not sure which one it was on when I bought it, K&N filter. I went to lake Murray to ride it for the first time after adding the pipe and the bottom end was great but at top speed it would start sputtering like it was rapped out and needing to shift gears but didn't have anywhere to go. I was racing my buddy with a 2002 scrambler 500 and I was a little faster off the gun but then he pulled away top end. His is totally stock which torqued me off. lol. Is something not adjusted right or is that all I should expect? (oh yeah, I had just added a new gates belt that day). It felt like it wasn't hitting top gear, but I could be wrong. Before I added the pipe and dial -a- jet I had raced some 500's at little sahara and ran with them stock. This last race was on dirt. Any suggestions? Thanks!

 

First thing is to make sure your air filter is clean.Then you need to do some plug checks,as soon as your bike starts sputtering kill it then check your plug,this will tell you whats happening.Another thing to check is your choke make sure it is set right.Later.

 

When you start sputtering like that, flip on the choke. If it gets worse you are running too rich, better too lean. Jet appropriately.

 

try another setting on the dial-a-jet,the smaller hole is the richest,
also,dial-a-jet work on all jetting circuits so be sure the needle and pilot jet are not to lean when lean it out for a bigger hole setting.

 

Also another mod for the top end (first adjust jetting like the others said) but get yourself a non-resistor plug-wire end. Chainsaw shop, or HPD sells them.

 

How do I know if it is running too lean? I ran it for about 5 min. to warm it up and put in a new plug then ran it for about 5 min to top speed and checked the plug and it was a tan color for about half the electrode. I can't flip the choke because every since I bought it it is stuck in the horizontal position. It has always started first tap on the starter and never flooded out or even acted like it was a problem until I added the pipe and the new belt. How would I get the choke un frozen?

Thanks for the responses I'm going try it all. I'm new to 4 wheelers, grew up on dirt bikes. These have alot more maintenance!

 

That is definately the problem then. Your plunger may be stuck in the carb or the spring may be broke. If the choke flipper (LOL) is messed up you would have to get a new cable. The choke plunger can get rusted in the carb sometimes. I would suggest figuring out why it is sticking and fix that before you do anything else.

 

I would check the choke. The plunger is plastic not metal! So it wont rust but the cable should be free to move. It sounds like you need a bigger main jet. Since you put the pipe on it is being starved of fuel. You should allways go to a bigger main jet when changing to a high performance pipe.

 

Hey 2Many, on my 98 400 the plunger is actually brass. Your right about the spring though, it can rust and stick.

 

Hey thanks alot guys. The choke cable is frozen. I did everything I could to free it up and its not moving. I'll get a new one and start from there. It never occured to me that could be a problem since it has never fouled a plug or acted like it was getting choked out until now. Come to think of it my buddies have always told me that it smoked alot and they hated being behind me on the trails, I just figured that it was a two stroke compared to their four strokes. I never worried about it since I was smokin them, hopefully I'll find power that I didn't know I had and stay far enough ahead that the exhaust won't bother them!