WR450 exhaust baffle


11 replies to this topic
  • boer

Posted January 19, 2006 - 02:29 AM

#1

will removing the exhaust baffle alone improve performance? If so, will I have to re-jet after removing only baffle? :thumbsup:

  • clark4131

Posted January 19, 2006 - 05:20 AM

#2

Yes. Maybe, depending on your riding environment, i.e. altitude & temp...SC

  • bg10459

Posted January 19, 2006 - 06:03 AM

#3

When I first got my bike I removed the baffle only (grey wire and throttle stop had been done already). without re-jetting I noticed a low through mid improvement, but I also noticed a slight hesitation at WOT. Supposedly it had been jetted before I bought it, but removing the baffle definitely affected WOT, requiring a larger main.
If you're trail riding at lower revs, you can probably get away with just a pilot screw adjustment. But if you'll be hitting the top end, you'll probably need to increase the main, maybe the needle too. Of course, all this depends on whether your jetting is bone stock or optimized for the current setup.

  • smr96

Posted January 19, 2006 - 06:36 AM

#4

I removed mine without re-jetting and it runs fine, much better than w/ baffle. My bike's bone stock except for free mods. I have the GYT insert for when quiet is necessary but mostly ride without baffle.

  • J_DOGG

Posted January 19, 2006 - 09:17 AM

#5

I use the Pro Moto Billet insert in the summer and run with the baffle pulled in the winter..... I ride ice!

My bike requires a jetting change for the two different setups but think it has more due to the air temp....

  • Beejay

Posted January 19, 2006 - 05:44 PM

#6

I removed mine without jetting & it runs fine, I'm at sea level in a fairly warm climate.

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  • boer

Posted January 23, 2006 - 06:38 AM

#7

I hope I got the terminology right. But All I removed was the black 1 1/2 inch long restrictor. Since then the bike starts easier and doesn't back fire after realeasing the throttle on long spurts or short reving at standstill. I assume it has done the bike a world of good then or not?? :thumbsup:

  • TWILES

Posted January 23, 2006 - 11:27 AM

#8

I took the one out of mine. I have the 2005 model. I put it back in till I can get whole muffler. It had alot more power in the mid area but it didn't run as good. I did the same to my wife's TRX450R. I put the HRC end peice on the stock muffler with about the same results. They don't hold the back presure right with the baffle out.

  • bg10459

Posted January 23, 2006 - 06:00 PM

#9

I took the one out of mine. I have the 2005 model. I put it back in till I can get whole muffler. It had alot more power in the mid area but it didn't run as good. I did the same to my wife's TRX450R. I put the HRC end peice on the stock muffler with about the same results. They don't hold the back presure right with the baffle out.


You probably need to re-jet after removing the baffle. Not saying an aftermarket exhaust wont be better, but you should definitely make more power throughout without the baffle if you're jetted properly.

  • TWILES

Posted January 23, 2006 - 06:47 PM

#10

You probably need to re-jet after removing the baffle. Not saying an aftermarket exhaust wont be better, but you should definitely make more power throughout without the baffle if you're jetted properly.


My reasoning for the back pressure statement is from somethings I learned a few years ago. I started out on atv's. We all raced and I was the only one with a 2-stroke. I learned from them that a 4-stroke pipe has to have a certain amount of back pressure for the motor to run right. A couple of my freinds had a major amount of work done. One was a 350X done to 370 with porting, stroker crank, and a bore in a 250X frame. The other was a 250X turned into a 318 with the same stuff. They tried a few different pipes and found out that they had to have the correct amount of pressure for the pipe and the motor to get along. The pipes they ended up with were TC hand built pipes. He used a SuperTrap 4 inch racing muffler and his own headpipe. The way the stock 05 WR muffler is constructed, I don't see taking the quiet tip out as being a good idea. The muffer is supposed to work with it in. It gets more power but not what I would call steady power. What I am refering to is on deceleration. It is too choppy. Jetting has nothing to do with that. Then when you get back on it, it hesitates. That is head pressure. Pulling the tip out just lets more air pass. It does really change the way the muffler works other than taking away needed pressure. A straight through MX type muffler would completely change the exhaust and let the motor run like the YZF. If I'm wrong I have got a lot to learn but that's how the lawn mower type motors( 250X / 350X) were explained to me by an engine builder 8 years ago.

  • bg10459

Posted January 23, 2006 - 07:04 PM

#11

Did you take the whole end cap off or just the baffle? I agree that you need some back pressure, but with just the baffle removed, I'm not sure you're reducing back pressure more than you would with an aftermarket (or YZ) exhaust. I also agree that the WR pipe is not the best option for performance, whether you pull the baffle out or otherwise. I only had mine uncorked for one ride before I switched to a YZ pipe, but it definitely (seat-of-pants test) made more (or better?) power everywhere except WOT (which I feel was due to too small a main jet). Then again, it could be differences between the years. :thumbsup:

  • TWILES

Posted January 23, 2006 - 08:05 PM

#12

I may be way off. I'm trying to learn about these new motors. There not really new but they are new to me. Like I said, I've had 2-stroke MX built atv's for the last 8 years. The WR is my first dirtbike. I bought a TRX450R and was really let down so I decided to give up on the 4 wheels and try something new. Mine is completely stock. I'm trying to learn as much as I can before I tear into it. Mabey I'll understand why I'm doing something instead of taking someones word for it. I've got the twist throttle down and the 2 wheeled part is coming(turning it still tough).. Once I understand how my bike works I can start finding its limits "comfortably". Then I'll know where to go as far as upgrades. I bought the WR to learn to ride a bike. I will probably keep it another year and trade off for whatever they are using in the GNCC's and try hitting a few. I know I'll put a slip-on on it but I doubt I do anything else as far as upgrades.
The information I put out is " as far as I know ". Feel free to correct me if I'm wrong. I'm trying to understand these motors because apperently I'm stuck with them for now on. My old pride and joy is my picture. :thumbsup:




 
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