Hi all. Just bought a 2011 KLX250 and have ordered a new slip on exhaust. It says on the site where I bought the new exhaust that rejetting is not required. Should I take this as correct or would I need to re jet? I havent done any other mods yet ie airbox mod. Thanks in advance

 

if it offers the same back pressure as stock, then no you wouldnt need to rejet (but you wouldnt be upgrading if that were the case).

If its more freely flowing than stock i would assume some amount of adjustment would be in order.

 

Thanks for that. Will fit it and see how bike runs after. If it has any problems then I may need to up rate the jets

 

May I ask what kind you purchased?

 

This one:

Stainless Steel SS70 Oval 225mm Silencer Exhaust Slip-on Kawasaki KLX250S 09-16 | eBay

 

I say without knowing your asl you will need a rejet. These klx' s are very lean from the factory.

 

I bought a brand new 2014 S, it came way lean, took a good five minutes to warm up and be able to rev freely. I worry about water in creek crossings so I replaced the air box snorkel with one from a KDX 200/220 which flows about twice as much air but is a perfect slip in fit for the stock hole in lid. If not worried about water, lidless gives most hp. Anyhoo, with the KDX snorkel flowing more air my bike was even leaner and ran crappier. I put on a four stroke works exhaust and installed the dynojet 2208 kit which richened it up nicely. Now she runs great with a nice linear spread of power, no surges or stumbles.