I'm saving up for a new slip on for my 2002 325 trail boss. Money is real tight these days though, so while I save is there a way I can mod the stock pipe for a little more power? Has anyone modded there stock exhaust, and how was it done? Did you notice an improvement of more than noise?

I was thinking of drilling a 1 inch hole into the center of the very back of the pipe this with the stock exit should be plenty. What are your thoughts on the matter?

 

You can open the end cap up a bit. Be sure to keep the spark arrestor in place. For the power gain, it would be hard to really notice it. Not like you're picking up 3-4 hp. It will sound a little less anemic though.

Other than the slip, you could get a K&N or similar filter, rejet the carb and do a little clutch work. Maybe a sprocket change. That's about it for those. You can make it a little more respectable, but it's never gonna be a sport quad.

 

Already put a spring in clutch with a razor belt, put a Uni filter on and did the air box mod, but can only open 1 to 2 of the holes right now as I have not installed my 145 jet yet. Maybe today I will get to that. It now lifts the front tires off the ground when I open it up, and I weigh close to 250. If I slide back a little I can ride a wheelie. Thinking if the mod on the exhaust adds anything combined with jetting and opening up more holes. This thing should ride a wheelie from take off with out me sliding back on the seat. Yes, it won't be a sports quad but to be a little respectable would be nice. Like a little higher top speed. So is their anyone who has modded stock trail boss muffler?

 

I didn't mess with the stock muffler. After I put the stage 1 RCR kit, I did change the front sprocket. Was spinning the tires too much in the soft sand and dirt.

 

I get that also just keeps spinning even at high speeds slides all around. Kinda fun though. Well until I find someone that has done it. I decided to open that plug to clean out the carbon. I ended up leaving it open for now with the new jet installed and it open it seem to pull quite a bit harder and for longer also, but that may just be because of jet. Was also able to open all six vents on air box. Wheelies no problem.

So anyone mod the stock exhaust?

 

Ok, I modded it today here is what I did. First I took it off. then took a long half inch drill bit and drilled the cone looking thing in the middle of the fin shaped I put four close holes in this popping what was left to the cone off. Then I took a long chisel and bent the fins all the way in. I'm sure someone with more tools and a welder could just take the inlet cap off and remove the baffle and weld it back together. I didn't have a welder and just had nothing to do so I started itching and used what was easy to grab. lol
The results not really notictable at idle. It's a little louder at wot and in between but not much. It has a noticeable low end to mid increase in power but top end seems the same or no real noticeable difference.

Now looking at the inside of this I bet someone with a welder could do as stated before. Then remove the original out let and weld it up. Then drill a 3/4 inch to a inch hole in center of the end cap. It would have a straight through design. You would have to add a screen, and I'm sure it would be quite loud. I wonder if any gains would be had like this. Someone with a welder and a trail boss want to try it?