Stock muffler mods on the cheap?

After buying a 95 XR250L I find myself financially unable to ad R headers and buy an aftermarket muffler. I have removed the snorkle, adjusted valves, & rejetted the stock carb with pretty good results but, I would like to de-restrict the exhaust. Is there anything I can do with a stock exhaust with an A1 muffler to open this bike up some? I pulled out the baffle and found there were no visable plates. Just a screen with baffling material wrapped around it. Advice anyone?

The "Gordon Mods" included grinding down a weld bead at the header junction to the cylinder head, which will help with exhaust flow. Pulling the baffle out also helps a bunch but does increase noise.

I drilled a few holes in the endcap of a stock 400 exhaust that I have on my 350. The drilling really made a big difference and the sound is dead on perfect, just a bit snarling and mean when on the throttle, but not as loud as most aftermarket.

I love it.

As far as opening up the muffler, I dont think so unless you are a welder. You can find R pipes on ebay. I just got an R pipe and header for $50 plus shipping. You just got to look around and be patient. I just found this link EBAY:

You still need a pipe though, the L wont fit the R header.

forgot info
The "Gordon Mods" included grinding down a weld bead at the header junction to the cylinder head, which will help with exhaust flow. Pulling the baffle out also helps a bunch but does increase noise.

I ground the exhaust headers today. I was amazed at how closed off the header was from the factory weld. I gained almost a 1/4" in diameter by doing that.

I drilled a few holes in the endcap of a stock 400 exhaust that I have on my 350. The drilling really made a big difference and the sound is dead on perfect, just a bit snarling and mean when on the throttle, but not as loud as most aftermarket.

I love it.

I would be interested in seeing some pics of your drilling mod. I assume it was the end cap you drilled? If so, how many holes and how big?

Now that I ground the header, re-jetted, and did a valve adjustment it is running much better. The bike ran MUCH better after the header mod.

I also found and subsequently cannot re-find a carb spring and tab mod designed to help with throttle lag. Does anyone know where I can find it? using the search feature hasn't netted me what I am looking for.

I took the spring off and wired the 2 together. Takes a little work to smooth the rotation but easy mod. Also closed the gap on the tab that actuates the pumper. Way better throttle response, eliminated hesitation and stalling for me.

Did you remove the push cable from the throttle as well? Also, I see you have the carb removed to work on it. How tough is it to get off the bike?

Gotta remove the carb to do any work IMO. too tight, how did you re jet with the cab on? Kept both cables. I dont think there is enough tension not to have the push cable also helps set your idle. As far as removing the carb... PITA! gotta loosen the air box and push to the side. But I recommend doing the AB mods as well. Remove the snorkel, the resinator (?) chamber and plug the hole in the boot. I drilled out the metal support bracket filled pop rivet holes with epoxy. I can PM you pics, let me know

Took me six hours and two pairs of hands to re-jet. I just loosen it from the front and back and twisted to where I could work on it. It was really hard.

So, the box has to be taken out? How did you keep track of what hoses and cables went where? I would be very interested in seeing pictures too. I can pm you my email if that would help? In fact I will do it anyway.

Thanks in advance

Mine was the Cali version so I had all the ECO NAZI crap on it, but really you only need the 3 vent hoses and obviously the fuel line. I will email you the rest of the mods I did.

I have pics of my XR400R muffler drilled, but I don't think its same as your XR250L muffler... also I don't know how to attach them?

Sorry I'm up on this photo attaching thing. I guess I'll have to get my kids to show me how?

Anyway I'm sure the 250's muffler is different from a 400's, but the pic should show you how we keep all the drilled holes inside the area of the spark arresting screen.

Anyway I'm sure the 250's muffler is different from a 400's, but the pic should show you how we keep all the drilled holes inside the area of the spark arresting screen.

I figured out where to drill on the A1 muffler cap. It did make a difference. So, other than my carb I think I am just about done tweaking for the moment. Thanks for the information.

OK tried setting up a photobucket account to see if I could post these pics



Thanks a lot for the pictures. I drilled mine out but may have to add a few more for good measure :bonk:

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