Have a 2009 Klx 250s that I bought a month ago and it came with a FMF Q4 muffler. I wanted to know how much horsepower is add to the bike with just that mod?

 

approximately 2.2kW, give or take .... :-P

 

That seems like a lot of HP for just a slip on. Also, whats up with the pipe popping during deceleration?

 

I bought a 2009 with a FMF pipe on it. The original owner did not rejet the carb nor remove the air box top which I thought was required. Did you have that done to your bike?

 

how does it ride. Hows the low end torque. High end torque. You like it?

 

No the bike has not been rejetted or airbox removed. I think the bike rides greating for commuting around town and light trail riding. However, the bike does feel like it needs to be rejetted. I have a Honda CRF 230f that I converted to a dual sport and had it uncorked and jetted. It feels alot more responsive then the KLX 250s. I can get the front wheel off the ground on the Honda 230f, but it seems more tricky to do a wheelie on the KlX 250s with out popping the clutch. I will definetly be jetting the Kawasaki because I saw great performance gains from just a few mods for the Honda 230f.

 

I got ***A LOT*** more gain out of rejetting than I did after adding my pipe.

 

What years KDX 200 snorkle will fit the 2009 KLX 250s?

 

FMF Q4 is a good all round exhaust & you will notice a power increase over the stock exhaust! Bonus is it sounds good but NOT that anti-social Two brothers loud!!

I'm at about 3000 miles with it now & it defo needs a muffler repacking job done. Getting louder & has a few little leaks where the muffler bolts onto the connecting pipe........shouldn't take more than an hour to do, biggest pain is ordering the stuff off ebay ($15) & getting delivered to Thailand

 

It rides good compared to stock. I do have two of em; one stock and one with the FMF pipe. Next mod is to go to a 50 tooth on the rear. I saw this below video that convinced me to change the sprockets next.

Bikes:



Video of modded KLX (not mine)
2010 Kawasaki KLX 250s test ride after some mods. - YouTube

Detailed Description of KLX mods (not mine)
2010 KLX 250s with some Mods walkaround. - YouTube