i have found a 1994 klx 250r muffler, will it fit on a 2007 klx250s without any mods to the bike. if it does fit how much louder will it be?

 

You will need a head pipe from the 250r or the 300r(they are the same, but different form the 250s) to fit a muffler from that bike. Other than that, no mods should have to be made.

 

it will be about the same loudness as stock, but if it has a buttplug, you can remove that and it will be louder. and the claim on this muffler making as much power as any other slip-on is based on the removal of the buttplug. that's a pretty old muffler, chances are the insides are rotten or rusted. but as stated, you'll need the ever increasingly hard to find 300 header pipe. but if you can round both up, you'll have the most economical mod anyone can do to the 250S based on power increases.

 

i have also found a header pipe off of a 93 250r so it looks like im in luck. and you are sure no new holes need drilled or mods need made. sorry for being hesitant but i just want to be sure.

 

Should be all good. Front end is really the only thing they have changed in 14 years.
250R is what we get here in AUS. You guys in the USA get the 250S. (some differences)