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eracer

2008 YZ450F Exhaust on a '08 WR 450?

23 posts in this topic

Hi,

I'm looking to change my stock exhaust on my '08 WR 450 (ist too restricted!:ride:). I've heard that installing the stock exhaust of the yz450f would be a good option.

Does anybody know if the stock '08 yz450f's exhaust system fit the '08 wr450f? Would you recommend it for enduro racing? I know the'07 fits, but I've heard some good things about the '08.

Thanks!

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Yes a 2008 YZ exhaust will fit. You can remove the pea shooter insert from the WR exhaust and jet it accordingly. That will make a huge difference and is quick and easy to do. You might try that before shelling out some $$ for a different exhaust.

Swapping out the header will give you the least gain. Concentrate on the muffler.

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Yes it fits. I have a 08 wr450 and got a new 08 yz450 pipe and header on this site for $150 delivered. I rejetted the carb at the same time I put the pipe on and what a difference. It pulls much harder and climbs to the top end very quickly compared to the stock system. Also the front wheel will come up now where it never did before. It is slightly louder but not too much louder. My son's 08 yz250f stock system is much louder than my wr450 with the yz pipe and header.

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As Im sure you know, there is no spark arrester on the yz silencer. You would want to see if that is required to race. The wr silencer has the spark arrester already and like stated above you can remove the pea shooter out of it which does make a big difference.

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Yes a 2008 YZ exhaust will fit. You can remove the pea shooter insert from the WR exhaust and jet it accordingly. That will make a huge difference and is quick and easy to do. You might try that before shelling out some $$ for a different exhaust.

Swapping out the header will give you the least gain. Concentrate on the muffler.

By the "pea shooter" you mean the spark arrestor or removing the whole piece? I've heard people that change them but never removing.

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By the "pea shooter" you mean the spark arrestor or removing the whole piece? I've heard people that change them but never removing.

I know there are pictures here that show you, but I cannot remember which thread it was. It shouldnt be too hard to find it.

The pea shooter is the inner baffel (about 5/8" diameter) that is enclosed in the outer baffel (about 1") on the tailpipe. You can take the end cap off to reveal the 5 or 6 bolts that hold the baffel onto the silencer. Then you can simply drill out the rivet on each side that holds the inner baffel to the outer. After you drill out the rivets you must remove the inner baffel. It will take a little carefull effert to remove it as it is pressed in I believe. Be careful to not bend or damage the mounting plate of the baffel as it is thin. It does open up the pipe a little and let it flow better.

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I'm running a full 09 yzf system on my 07 with the PMB sparky end cap and tapered quiet cone inside. It's just under 98db. To pass sound at a race I have to use the turned down quiet buttplug with a slight noticeable power loss.

The best advantage is the weight savings. The stocker is at least 3lbs heavier, and it just clears the side #plate.

I got lucky and got the whole system with the end cap for 2hun from a gracious TT member.

CCworkparty0072.jpg

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I have the 08 shorty on my 08 WR. Works well. Not loud like some aftermarket exhausts, well protected by sidecover and allows you to use mudguard easily to lift bike when needed. I tried 5 different exhaust combos and liked this the best. The FMF factory 4.1 gave the most power but was loud and easily damaged. It was also too snappy for tight single track. The YZ shorty is smooth and easy to use, similar to the FMF Q4. I use the standard header which requires the WR sleave to fit which is a little loose in the YZ pipe. I put some muffler bandage around it to fill the gap and all is good. Some others have just tightened the clamp up further to make it work.

I think that the sleave from a YZ250F 07 model may fit perfect as it has the same header diameter as the WR450 and the silencer should have the same inner diameter as the YZ450 but I havnt tried to confirm. If you get the YZ header you wont have a problem.

Cheers

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Thanks for all your replies guys. I think I'll try the yz '08 muffler with the stock wr header, I'll let you know how it goes!

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Thanks for all your replies guys. I think I'll try the yz '08 muffler with the stock wr header, I'll let you know how it goes!

You'll need a YZ header to go with the YZ silencer. Larger than the WR.

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You'll need a YZ header to go with the YZ silencer. Larger than the WR.

I agree that he should just try and find the complete yz system, But with a new WR pipe gasket the stock header pipe fits the yz silencer. They aren't cheep but you cant re-use them once heated up. At least I destroyed one trying to get it out.

Bigger diameter = more flow, get a yz head pipe too.

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Yep, Header before muffler if you go that way.

The WR muffler is too small to work with the YZ Header, as stated.

Best mod is a complete YZ exhaust setup. Truley one of the easiest mod's labor wise.

Night and day power on my 09 WR450!

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.

.... and if you want to remain in "Stealth mode" with the extra power......

Use the YZ450F header and open your stock muffler right up!

Click here: http://www.thumpertalk.com/forum/showthread.php?t=349760&highlight=Modified+Muffler+saves+big+%24%24%24%24

Stock muffler dimensions:

layout2.jpg

40mm diameter all the way through, yet quieter than most aftermarket mufflers:

wr450f_oem_exhaust_mods_oct_2008_4.jpg

Greg

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Does anyone know if an '09 yz250f pipe will work on an '08 wr450? My son wants an aftermarket pipe for his yz250 and if his pipe would work on my wr450 I might be more apt to buy him a pipe...Thanks

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We have a 08 wr450f and 08 yz250f and planning to do a little work this weekend on them. I will see if it bolts up for you.

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You can use a 2006+ YZ exhaust system on your 2007+ WR.

It tried the YZ system for a while, and ended up switching back to my stock WR exhaust.

I found that the YZ system was too loud for trail & dual sport riding compared to the stock WR system.

When I compared weights, the YZ full system was 2 pounds lighter than the stock WR system.

My WR seemed to make more midrange and top rpm power, but lost a little power off idle and in the lower rpms.

I removed the stock pea shooter from my WR system, and added the PMB tip.

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We have a 08 wr450f and 08 yz250f and planning to do a little work this weekend on them. I will see if it bolts up for you.

Thanks, I just bought both bikes (New left overs)and I wont get the 450 for another week or two... or I would just try it myself.

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