01 426 White Bros. Exhaust Plates

I have an 01 426.(Have had bike for 3 weeks). It has the White Bros. E-Series exhaust. It has the thin plates between body of exhaust and tip. It had 10 plates installed. last night I removed all but 4 plates. Is it just me or did this reduce exhaust sound? And if so , and I remove the other 4 plates will this hurt my bike in any way. A better rider maybe could tell a difference in performance but I sure couldn't.

I will be repacking the exhaust this weekend and hopefully that will help lower exhaust sound some more.

Any thoughts, ideas, instruction would be greatly appreciated.

I have an 01 426.(Have had bike for 3 weeks). It has the White Bros. E-Series exhaust. It has the thin plates between body of exhaust and tip. It had 10 plates installed. last night I removed all but 4 plates. Is it just me or did this reduce exhaust sound? And if so , and I remove the other 4 plates will this hurt my bike in any way. A better rider maybe could tell a difference in performance but I sure couldn't.

I will be repacking the exhaust this weekend and hopefully that will help lower exhaust sound some more.

Any thoughts, ideas, instruction would be greatly appreciated.

according to the instuction sheet i had on mine, gave it to the guy who bought the bike, 4 is the min. wb recommends running on the E. And yes less plates, less sound, but those "silencers" were way loud. I own a db meter and mine with 4 plates would idle between 94 and 95 dbs..

At 10 I bet your ears would ring after riding it..

Yes sir, it was pretty loud. Actually it's still pretty loud. Hopefully the repacking will help. Should there be any difference in performance? Or would it be so small that you couldn't tell? I'm not going to need to rejet or anything am I?

Thanks for help.

P.S. What part of Texas you in? I'm in Longview. (Northeast)

amarillo.....

and mine ran a little worse with 4 plates, but not enough to cause me any problems and no rejet for me.

jay

I had the same exhaust on my 2000 426. Do you have the spark arrestor plate on it? If not, then the plates don't seem to make much difference either way since it's a straight shot through the middle of them. The plates DO make a difference when you have the solid spark arrestor plate on (goes on last over the outside plate). If you have that on, you MUST have at least four silencer plates on or you will be virtually sealing off the opening with the spark arrestor. I accidentally did this and, somehow, don't ask me how, it still ran.

After all was said and done, even with only four plates, it was still too loud for me so I went back to the stock pipe, repacked it, and added a DB Dawg silencer and spark arrestor...kind of a poor man's Pro Moto Billet silencer. I had it tested at Carnegie and it registered 94 decibels at 4500 RPM, well within limits. Unfortunately the DB Dawg spark arrestor is not USFS approved even though it easily meets their standards. According to DB DAWG the approval process is prohibitively expensive.

Good to know about not having to rejet.

I work for a chemical co. and come to amarillo a couple of times a year. Or actually I just stay in amarillo. I go to Borger and the Fine refinery to work. I like the drive from amarillo to borger. I have never seen a tornado and I feel I've got a pretty good chance on that stretch of road. My wife and the guy I work with think I've lost my mind. But you know there are just some things you want to see. For me that is a tornado. I don't want to get too close though.

divebobber,

I don't have a spark arrestor on my exhaust. It just ends with an oval cap/hold plate thing. I know it's not a spark arrestor because last night I fired it up and saw a few sparks fly out. Guess this is packing???

Anyway I don't have the money right now for new exhaust. I need new sprockets and chain first. maybe someday I'll upgrade to a quality exhaust. But right now guess me and the neighbors will have to deal with it.

yep, you have a good chance of seeing one in that area. you probably drive right past our main riding area going there. There is a bridge that crosses a river and we ride about 30 miles west and about 10 miles east of that.

the E should have a plate under the end cap . Mine actually said spark arrestor right on it. Without that plate, the exhaust does not deflect out thru the plates like it is supposed to. that may be why it is so loud. You should not be able to see into the silencer from the back.

I ended up putting a stock one back on mine. got it used pretty cheap..

Mine is just as Jhendr3702 described. The oval end plate, if it keeps you from being able to look down into the muffler, SHOULD have "spark arrestor" stamped on it. And I could see how you might still see sparks with it, since it isn't a screen type arrestor.

The gaps between the plates are suposed to arrest any spark that may try to come through.

I removed all my spacers and the plate and installed the Quiet insert (actually a straight through pipe that bends down just a bit) - I don't think white bros. ever looked up the meaning of quiet.....:excuseme:

I don't think white bros. ever looked up the meaning of quiet.....:excuseme:
The R4 should have been called an amplifier, not a muffler.

I had this pipe on my 426. Yes, removing plates will reduce sound output, but also restricts airflow / performance. I went from 8 to 4 plates (the minimum recommendation) and it was quieter but I lost some power. I think the quiet insert would be the answer. I couldn't find one so I went back to stock and put on a spark arrestor.

Matt4x4, what brand quiet insert did you use? I was looking for one for my White Bros pipe and couldn't find one.

Thanks for help guys. I don't think I have a spark arrestor. I can look in the end of my pipe and see the cylinder head,,,I know, but the hole is so big it looks like I should be able to. Also I can see strands of fiberglass or packing sticking thru the holes of the insert. So I guess that means time to repack.

I also took out all but 3 of the plates. My god it's still freakin loud. But, It didn't seem to affect the running of it.

I ordered a set of sprockets and a chain today from RockyMountain. I got the 14 front and 52 rear PD. And PD o-ring chain. My rear sprocket is in bad shape. The front one seems to be holding up better but I figured I would replace both then I'll know what I have.

I would be interested in that insert Matt if you happen to know where you got it.

Thanks again for help

I had this pipe on my 426. Yes, removing plates will reduce sound output, but also restricts airflow / performance. I went from 8 to 4 plates (the minimum recommendation) and it was quieter but I lost some power. I think the quiet insert would be the answer. I couldn't find one so I went back to stock and put on a spark arrestor.

Any word on how much quieter it gets with new packing?

Diverbob - the quiet insert is made by White brothers for the e series - you won't be able to get one - I got the last one available.

If you want to make one - take one of your spacers and use it as a template for a plate - into which you can drill a hole for a 1.5" diam. pipe - the pipe on mine is about 2 inches long and has a 30 degree angle in it - basically a straight 2" pipe was cut at a 15 degree angle - one piece was turned half way around and the cut was welded back together - the downward bend is on the inside of the pipe. To be honest - it's really far from quiet but the flow from the pipe certaily increased.

I have the E-Series on my 426. I run 6 plates. But if you do not have the end plate it doesn't matter if you have 1 or 10 of the spacers in. The whole concept of this pipe is having the end block off plate and being able to "tune" performance by removing or adding spacers to control back pressure and airflow. With out the end plate in you actually will lose horsepower over the stock system.

When you say "end plate", is this the one that is about 1.5 inhes deep and has a curved crown? Or is there actually a plate that covers the end of the silencer?

I went out to the garage and snapped a couple pictures of mine. Its easier to see so you know what I am talking about. Here are pictures of the side and back of mine.

whitebros2.jpg

WhiteBros1.jpg

Here is another pic. I put some arrows on to show the concept of the exhaust. Where the arrows are is where all of your exhaust gasses should be coming out of. None come out of the end because of the plate pictured in my previous post. You can see it is supposed to exit between the gap between each spacer. This is why adding or removing spacers changes the exhausts performance and tone because it allows more or less airflow when the plate is installed on the end.

wbexhaust.jpg

First, thanks for reply and pics. Now I know exactly what I'm dealing with.

Looks like I've got some work to do. Everything on mine is the same, except what I would guess is the most important part of the exhaust - the block off plate. Mine has 6 of the rings and the end cap, but no solid plate.

If I find this plate, I should expect it to be a little quieter and have better performance? Don't get me wrong, it runs pretty good now. But I rode a buddy's 2004 YZ 250 and couldn't really tell the difference in power.

Thanks again for reply, Scotty

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