YZ 125 Aftermarket Exhaust

[bulldog57]

This has probably been discussed somewhere, but I can't find it. 2011 YZ125, what is the best aftermarket exhaust setup for MX. Which would give gains or improvements in the overall bands/performance. Procircuit, FMF???? Do I have to rejet for the pipe?

Edited May 24, 2011 by bulldog57

[125 racer 981]

I have a 06 Yz 125. I have both the Procircuit works with R-304 shorty and the FMF fatty with the shorty. Both pipes will make a change compared to stock. For me the Pro Circuit setup made the power go up into the higher RPMS which i liked. Then I got the FMF set up and that made the power really good. To me, it feels like the FMF set up gives good bottom and top end so it revs out well. Also the FMF shorty is shorter then the Procircuit so its going to be a little louder but it sounds great! The expansion chamber on the FMF is much fatter and has different bends compared to the Pc. If I were you, I would go with the FMF set up. I got my FMF brand new on ebay and saved about $30 from retail price with free shipping on both items!

I believe the 11s have updated jetting with a 430 main and a 40 pilot. I made my 06 the same jetting

Main 430

Pilot 40

Needle 6BFY42-74 at Position 4

And I run 1 gal of 76 91 oct to 2 gallons of VP 100. 2:1 ratio

You may be fine with your jetting but make sure if you get the Pro Circuit or FMF that you check your plug alot so you dont cause damage for any reason.

Hope this helps and hope that 125 sounds good!

[Holy Smoke]

I think you will find that the OEM yamaha exhaust is pretty good and better than most aftermarket pipes. A lot of bikes can benefit from aftermarket exhaust and reeds the

yz125 is just not one of them.

[motojase316]

Either or of those two will liven up your yz125... I ran fmf Rev pipes in my 125 days and Pro circuit works on my 250s and boyesen reeds.

[racerjon777]

Ive got a PC Platinum/R304 shorty combo. I like the sound, and the top end speed is ridiculous, but I hate having the powerband so 'lightswitch' like. I feel like Im going nowhere, then all of a sudden Im looking at the sky. I dont like this feeling, which is why I am going back to stock pipe on my YZ.

Ive read the best setup is an OEM pipe with a shorty silencer, so this is what I am going to try next. When I began riding this bike, I threw the PC Platinum on there from the get-go, so ive gotten used to how it rides, however the increased bottom should be a welcome change for me.