Im new to this whole bike modding thing and i have a few questions. I just purchased a Big gun evo slip on for my klx250sf. now i know that my carb is going to need some attention. Is it really necessary to buy a 60 dollar dyno jet kit, or should i just buy a new main jet? Also, if only the main jet needs replaced, what size should i get and where is the best place to purchase them?

 

I don't know about the Evo slip-on, but with my FMF they said you don't need to rejet if that's your only mod. So if that's all your doing I'd try it first and then decide if you need to rejet.

I'll let others advise you on a new kit or not. I will say the kits also include the needle, spring and spacers.

 

thanks for your input. How did you bike run with the fmf slip on and no rejet? and the only reason on why im jumping to conclusions on re-jetting is because the stock pipe had a catalytic converter in it i believe....so once you remove all of that it should open the engine up....so how did yours run after you put the fmf on it?

 

Mine ran fine with just the slip on. But once I put the K&N air filer in I had to rejet.

 

I got the powercore 4 right now and jsut ordered the dyno jet kit, if i get the k and n and take the snorkel off should I run stage 1 or 2?

 

I did the stage 2 based on my mods.

 

So bike runs fine with just the fmf pipe even with no rejet? Any increase in torque?

 

I didn't really notice a difference until I did everything. The rejet made the biggest difference.

 

thanks for your input brien

 

theres definitely more top end, but I almost want to say I had a decrease on bottom end..