YZ250F muffler on!

[red2003]

Got the muffler on the DB07A today. I pulled the whole exhaust off and it was apparent that the header pipe of the YZ250F was NOT going to happen. The exhaust port in the head was too small to even accept it, and if it had, the bend was not even close. Judging by the size of the exhaust port, I don't believe it would gain anything anyway. Note, my stock header pipe was also buggered up with extra weld as has been mentioned here already. 5 minutes with the die grinder took care of that. OK, so next best thing was replacing the muffler at least. I cut the stock pipe off right above the tool box where it flanges out to the size of the stock muffler. The pipe at that point matches right up to the pipe on the YZ250F muffler, about 1 7/8". I ground everything to match and welded it up. Note, the YZ pipe is some kind of stainless steel alloy, VERY difficult to weld and paper thin. If you aren't an experienced welder, don't attempt this mod! The muffler sounds great. Much lower note, and no louder then stock. Might be a littler quieter actually. I have not road tested it as there is a foot of snow on the ground here. It definately sounds snappier, but I wont really know if I helped anything besides the sound until I get it out on the road. I am pleased with the mod and if nothing else, it looks and sounds better IMO. I still have to grind off a few brackets that aren't needed and then polish it up, but that's next weekends project!

http://www.chinariders.net/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2454&g2_serialNumber=1

Tacked in place:
http://www.chinariders.net/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2506&g2_serialNumber=2

Finished and back together.
http://www.chinariders.net/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2509&g2_serialNumber=2

[FMYStreetRacer]

go to imageshack.us and host your picture there. then post them up.

[red2003]

go to imageshack.us and host your picture there. then post them up.

I have them HERE in the gallery. I have the URL links, I just don't know how to actually "link" them in the post. I have tried the img button, and followed the format, but it doesn't seem to work :(

[Roketarider]

I looked at them...looks good! If you know how to weld and get a deal on one, simple cheap mod.

I am going to smooth out the weld on the front of the pipe inside.

[frostbite]

If you're using Firefox/Mozilla:

To link images from the gallery simply right click on the image you want to link to and click on 'Copy Image Location'.

In your forum post type the following to embed the image:



Now place the cursor in the middle of the quotes and right-click and select 'Paste'. You should now see something like this:

http://www.chinariders.net/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2454&g2_serialNumber=1

If you're using Internet Explorer:

Right click on the image and click on 'Properties'. A small window will open. Highlight with the mouse the line marked 'Address (URL)'. Right-click and select 'Copy'

In your forum post type the following to embed the image:



Now place the cursor in the middle of the quotes and right-click and select 'Paste'. You should now see something like this:

http://www.chinariders.net/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2454&g2_serialNumber=1

If you have any issues/questions just send me a PM. I'll be adding the above to an FAQ sometime soon.

[red2003]

Got the pics figured out. Thanks for the info, definately would be benificial in the FAQ section. :D

[FMYStreetRacer]

i saw them before and it looks good. you have inspired me to get a muffler now as well.

[red2003]

FYI, I picked up that complete exhaust on eBay for $22 total including shipping. The auction went for $5.50! It's off an 01 YZ250F, but any YZ250F, CRF250, etc would work since you gotta hack into it anyway. Cheap / easy mod if you got a good welder handy. Took about an hour total to do. All I have left is to grind off the brackets on the side that held the rubber stoppers against the YZ plastic. Not needed for this application and looks kinda sloppy IMO. You'll LOVE the new sound! Only thing I goofed up was not getting the bike inspected by the DMV first. I have to sand off the back of the muffler where it clearly states "This exhaust system is not intended for on road use. Closed course only. Not EPA approved, yadda, yadda, yadda". A few minutes with the DA and it'll be long gone :D .

[red2003]

Well, I couldn't wait until this weekend so I pulled the bike in the shop and prettied up the new muffler. I ground off the unused brackets and polished it all up. Can't tell it wasn't made to go on there, ya know!

http://chinariders.net/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2536&g2_serialNumber=2

[fatboy250]

As far as performance, have you noticed an increase?

[red2003]

Wont know 'till Spring. We got a foot of snow on the ground and ice covered roads. It definately sounds snappier, but I haven't got to test it out on my "seat of the pants dyno" yet. First warm (above freezing) day we get, I'll check it out. It saves about 4 or 5 lbs of weight also, so that can't hurt. It definately sounds better and looks MUCH better. Heck for $20 and an hour of work, I'd do it again in a heart beat.

[fatboy250]

Yeah, right on with the looks. Are you planning any air filter mods. Dad and I tweaked ours this past weekend with a pod filter and air box removed. We adjusted the brass air mixture screw out 2 1/2 turns, dropped the c-clip to last position, and they are running great. Even start cold with very little choke and idle near perfect in seconds. Transition from pilot jet to main jet during slow roll-on acceleration is seamless. The only other prior mod for ours was drilling out the baffles in the stock muffler.

[red2003]

Yeah, I think I'll do the filter too. The only concern I have is how cold mornings might be kinda fussy. I plan on riding this thing any day it's above freezing. Maybe I could make a pre-heater out of heat resistant tubing to plumb some of the exhaust heat onto the filter. Nice to hear yours is running well. With the filter and exhaust mod, that's gotta give us a few more horses I would think. What size pod filter do we need? The carb intake is like 1 7/8 right? I'll get one coming. BTW, after you remove the filter box, is there any more room under the seat for storage? I gotta figure a place to keep gloves, registration papers, etc.

[fatboy250]

I believe it would be a 39mm K&N type cone filter. I used a 42mm and it wasn't snug until I really tightened the band clamp. If your's has PZ27 on the side of the carb then it would be the same.

Under the seat would be a great place for storage, but you have to take side panels off to get to the seat bolts. However, the battery would fit I believe. This would have been a much cleaner design, but I guess they did what they had to do.

I keep mine in the garage, never really gets below 40-50 I guess. Haven't had any problems with the new carb settings. Before, I just had to make sure the choke was pulled all the way up (closed) and it would start on the first try. I rarely have to choke it now.

[Savage]

I'm wanting to mod my exhaust someday down the road but the achilles heal I see with the exhaust is the 180 degree bend that's not mandrel bent.

You guys have a clue what make/model pipe would come close to fitting and matching up? Or is that the million dollar question? :D

[red2003]

Dont worry about the bend in the header pipe. The exhaust port of these engines is so restricted, the stock pipe flows plenty. Get a good muffler, or drill out the stocker, and that's about as good as it gets, unless you want to pull the head and port it.

[Savage]

Boooo :cry:
Time to get out the dremel I guess. lol