Ok I need some advice. I am running a 2003 Scrambler 500 with a white bros e-saeries pipe, clutch mod, k&n air filter and it has had a jet kit put in it(I bought the machine all this way) but I am more of a trail rider and it is sooting up the plug very quickly, heck you can gun the engine and see black exhaust. I am goign to pull the carb apart but was wanting some advice on what i should set the needle at and what jet i should have in there for my type of riding, which is on trails and I am not going all too fast. Thanks for the help and be safe

 

I ran a 160 main jet with the air/fuel screw 2 turns out and the neddle jet in the stock position with just my HPD exhaust.

 

Hey Jason, what is the stock position. I pulled the plastic and tank off, found that the plug was as back as can be, replaced it. I thin pulled the diaphragm cover off to adjust the needle and it was at the second from the top setting so I put it to the top and tried it. I also noticed that my manual said to put the washer in before the needle, but there was no washer in there, only the needle, e-clip, spring with little plastic end and the diaphragm. It has been modified before though as the diaphragm cover screws were stripped really bad. I didn't take the time to see which jet I had though, how do you pull the jet out, can it be done on the machine or should I pull the carb off. Thanks for the help though.

 

There should be a spacer washer too. It is called a "ring" on the partsland diagram #6. I believe that it goes on the needle itself. If this is missing, it is possible that it could be causung it to run rich. The manual mentions that a faulty needle and seat causes a rich condition. But, to be honest with you, I can't recall the stock position of the needle. I want to say that it is on the second clip down (?) The main jet is easy to change. The best way to get to it is to unbolt the carb and rotate it over. You need to remove the float bowl drain plug. Then right through that hole you will see the main jet. Stock is a 155. I don't know what you have in there, but most that do need to rejet go with a 160. That is what came with my HPD exhaust. Also try adjusting your air/fuel screw to 1 1/2 turns out from lightly seated