twin muffler ???

[sirscottf4]

has anyone ever cut down the mufflers on a crf ? if so what did it do for performance? or what will it do?

[Kevin415mx]

I would think it would hurt the performance because the bike is designed to work with the mufflers the way they are. If u were to cut ur mufflers u would have to make other changes.

[motodogg01]

I had an 04 CRF250R with a Yosh system on it that the muffler had been shortened on. It was shortened by the previous owner to gain more bottom-end power, less back pressure I think. Made that bike sooooooo load though. Man, no kidding, it was LOUD!! However, the motor did rip from bottom all the through the top!!

I don't know why it would be any different for a stock system, however, I've never done that mod to a stock system so I couldn't say for certain.

Edited April 5, 2010 by motodogg01

[Charlie C]

Usually it works the opposite. If you increase the back pressure, you'll increase the bottom end (more torque). If you decrease the back pressure, the bottom end will suffer and top end will gain a bit.

[sirscottf4]

so is it not the same for 2stokes? ex.fmf shorty..we always hacked our mufflers on 2strokes.

[Charlie C]

so is it not the same for 2stokes? ex.fmf shorty..we always hacked our mufflers on 2strokes.

Once it hits the midrange, it rev faster, but take the silencer off and the bottom end goes to crap. I remember doing the same thing with the 2 strokes! If it's choked up, everything suffers. Some of the old Honda's had a screen in the silencer probably for woods riding and they would clog up and run like crap.