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2008 WR 250F Exhaust System

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Hi guys Iv got a 2008 WR 250F and were looking at fitting a performance exhaust system to it to gain more grunt particualy in the low to mid range power because I ride tight trails down here in Aus. What other mods should I be looking into? I would appreciate some suggestions.

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Hey BADVH, I have the 07 and have a Dr.D full system on, works very well, I hear the GYTR is also good on the Wr's. Have you done all the free mods posted here on TT?

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FMF Factory 4.1, FMF power bomb or if you got more money mega bomb header, Hotcams Stage 1 cams, Hi compresion 13.5 to 1 YZ 2008 piston, 290 bigbore kit are all popular choices for more bottom end. Choose 1 option at a time as if you ad all at once you wont know what works best and you might end up with too much bottom and not enough top end. Ive just ordered a FMF Factory 4.1. Ill let you know how it performs. I have a PMB exhaust insert and have drillled the rear internal baffle and its much improved from stock. Ive had 2 other WR250Fs which on the 04 I had a staintune exhaust and a Hotcam exhaust cam and a 05 which also had a Hotcam exhaust and a PMB insert. The 07 and 08 have different standard cams from the earlier models and produce more midrange therefore I dont think the Hotcams would make as big a difference.

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hi.i have just got a wr250f put a fmf 4.1 system on and it works really well it pulls hard on the bottom to mid talked with fmf and they suggested 1 turn on the fuel screw out and it seems to be fine riding in about 800 ft above sea level.

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Thanks guys for the feed back. Has anyone used a pro curcit system?

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you will loose your grunt if you go with a free flow exhaust. more grunt, keep stock can, get a megabomb header and you will gain some top end, lower sound, gain a ton of bottom end.

also, hotcams stage 1 give you more low end.

you can also gear it lower, get a big bore kit, or a stroker crank

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you will loose your grunt if you go with a free flow exhaust. more grunt, keep stock can, get a megabomb header and you will gain some top end, lower sound, gain a ton of bottom end.

also, hotcams stage 1 give you more low end.

you can also gear it lower, get a big bore kit, or a stroker crank

Free flow exhausts normally improve bottom end power more than topend. Just ask anyone who has made the change what was the biggest imrpovement.

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For the price of an exhaust nothing will be the hp increase that a big bore kit will give you. Dollar for dollar it's the best money spent.

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Free flow exhausts normally improve bottom end power more than topend. Just ask anyone who has made the change what was the biggest imrpovement.

no that is not true. I have the ability to go from a WRF 82db muffler to a free flow exhaust.

you can feel the tractor power go to ferrari power. lol. try it yourself, look at dirtriders dyno's.

pipes magnify certain parts of your powerband, and takes away from others, like cams, it tunes them. thats why the megabomb is awesome, adds everywhere, or atleast retains and doesn't lose(my topend seemed unchanged but bottomend was awesome)

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I've been riden a newer 250 before and after a slip on and I noticed a big difference in low end punch. Then again, it could have just been me. I'm a poor judge of power/speed. I took this off of FMF's website. I don't know how true it is.

"Factory 4.1 SL – Stainless Steel (S/S) Midpipe

Titanium slip-on muffler with stainless steel midpipe. Available in natural titanium or blue anodized finish. Fits stock or FMF header. - Boosts low-mid torque, broader powerband, more over-rev."

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i just bought my 08 wr250f ,i had a full (BILLS) made in USA header pipe and muffler put on and re-jetted to suit.

and is bloody great in perfermace,sound,look's and detail.

great bike too arrrr! no more kick starting.

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here is a dyno, be dirtrider, showing that all the pipes, including FMF's, lose power in the bottom end, and gain in the top

http://www.dirtrider.com/tech/141_0303_2003_yamaha_yz450f_exhaust_test/index.html

That's funny. The old butt meter tells me it feels a little stronger down low. Again, I'm a poor judge of speed. To me, the slip on woke my bike up. How much has slip on's changed sine that write up? A few of the slip on seemed t give a 1-2hp increase and some loss power.

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if you could have more power everywhere. factory would already do it. its a compromise. you tune the engine to breathe great at a certain rpm.

also look at the time it takes to rev on the dynos. pipes don't ad much power. but if they can shift the torque curve higher. you will gain more power. hp=torqueXrpm/5252

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WR250F Captain makes a good point. Torque and HP are not the same thing. The charts may show that you lose HP down low but it doesn't show the torque that was gained by the pipe.

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WR250F Captain makes a good point. Torque and HP are not the same thing. The charts may show that you lose HP down low but it doesn't show the torque that was gained by the pipe.

Good point. I know with cars, you will always get a gain of power (HP/ TQ) by switching to a freeer flowing exhaust.

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The dyno graphs shown relate to a 2003 YZ450F. They are fitted with a free flowing exhaust from standard, so the results aren't comparable to a restricted WR exhaust. The diffrence between the FMF Q and the others is of more revelance if comparing to a WR exhaust. At 4500rpm their is 7.6 HP between the FMF Q and the FMF Titainium 4 slip on. Showing that a free flowing exhaust improves bottom end. Then you can see in the mid to topend the results are similar with only 1/2 a HP difference in peak power.

Ive never tried a FMF Q, but most reports ive read say they improve bottom end over a standard WR exhaust therefore the difference between the Titainium 4 and the WR should be even larger.

The FMF Titainium slip on also is stronger than the standard YZ450F exhaust everwhere except between 5000 and 5500rpm and also 11500rpm. The dyno only shows from 4500rpm where the FMF is stronger in the bottom end.

Again this is not relevant to a 08 WR250F as it is a different bike, and all the exhausts in this comparison would now be superseeded by new models.

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blatchy, i tested this one out on the street. with my stock can, my front end wheelies very easily and low rpms, with a free flow exhaust, all the torque is gone. the q which i have ridden a wr450f with, doesn't give it more bottom end compared to stock, just better overall power, better low end compared to other a/m parts. the q is a nice piece for peace and quiet

The dyno graphs shown relate to a 2003 YZ450F. They are fitted with a free flowing exhaust from standard, so the results aren't comparable to a restricted WR exhaust. The diffrence between the FMF Q and the others is of more revelance if comparing to a WR exhaust. At 4500rpm their is 7.6 HP between the FMF Q and the FMF Titainium 4 slip on. Showing that a free flowing exhaust improves bottom end. Then you can see in the mid to topend the results are similar with only 1/2 a HP difference in peak power.

Ive never tried a FMF Q, but most reports ive read say they improve bottom end over a standard WR exhaust therefore the difference between the Titainium 4 and the WR should be even larger.

The FMF Titainium slip on also is stronger than the standard YZ450F exhaust everwhere except between 5000 and 5500rpm and also 11500rpm. The dyno only shows from 4500rpm where the FMF is stronger in the bottom end.

Again this is not relevant to a 08 WR250F as it is a different bike, and all the exhausts in this comparison would now be superseeded by new models.

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What you have found with the exhaust may be a result of the stage 2 hotcams that are set for topend gains.

Im afraid that otherwise we will have to agree to dissagree.

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What you have found with the exhaust may be a result of the stage 2 hotcams that are set for topend gains.

Im afraid that otherwise we will have to agree to dissagree.

this was done before my cams, with all 3 of my mufflers. and a uphill speed test.

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