Big Gun QUIET exaust...big power loss

Just finally got to ride my 02 426 with my new Big Gun Quiet exaust....

Yes its alot quieter, it also lost tons of power. Seriously it just killed my bike! I think an xr400 could walk away now!

I just wonder if I could have done anything wrong. Ive installed several 4 stroke exausts on bikes so Im not a beginner or anything.

I left the jetting stock but I cant imagine jetting being responsible for 15+ hp., maby more.


Call Big Gun directly and someone will be able to give you some advise/input. 909-948-7029

I got the Big Gun for my 250F just the race series not the quiet and I had great performance gains. I went with the jetting specs. suggested by Big Gun. When I asked about the quiet core he said that you will lose some power on top.

All I know is it's better to talk to the guys who made the pipe to get the best input on what to do.

Good Luck!

although i ride red (2001 XR400) - i just did the same thing - was running the BG race version and then decided to help the eco-cause and "do the right thing". so i did a quiet core insert and their silent sport packing. the thing is a turd now, i'm not impressed in the least and kinda disgusted and i'm pulling the core when i have a free hour.... let me know what big gun says - i wrote them for jetting spec's, they sent me initial (BG Race) spec's for supposedly my bike. i'm wondering though what they gave me, my keihin stock main = 162 - they told me to go to a 155, i did, the plug read ok, i just thought free-flowing meant sliding more air thru, hence needing more fuel. anyways - i spent $50 on that Q core that, then after i saw it, I could have brazed in the baffles myself for .10 cents in metal, i wrote them agin to get spec's for the QC and they said they didn't have a suggestion.... bottom line - that core stinks... let me know how you make out,, best of luck....

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now