Delkevic or other header suggestions?

[sleddog]

I have a 07 WR450 with stock header and FMF powercore slip-on. I saw this Delkevic titanium header (powerbomb look-a-like) on Ebay and thought it might be worth a try. Looks like the stock heat-shield fits on - definite plus. Anyone try one? It says it fits a 06 YZF which I think should fit the 07WR?

If I decide to go with a stock YZF header, is there a preferred year that works best?

And last, do I need to change the exhaust cam to see any difference. I'm planning on changing to YZ cams eventually, but plan on riding a while before I do it.

Thanks for any input!

[sledhead999]

I've wondered the same thing. Does the YZ450 use a lead donut between the head pipe and the muffler. I think the YZ has a bigger head pipe to start with. My brothers 03 YZ450 has a Yoshi full exhaust, no lead donut, just a flared slip fit.

[Just_a_trail_rider]

I bought the FMF titanium powerbomb header for my 450. I could not tell the difference in power at all. The FMF Factory 4 pipe made a big difference though. I raced my 450 for two years and couldn't tell the difference. I am now back to the stock header because the titanium header dents really, really easily.

What are you hoping to gain with the header? I tried the header approach and got nothing but a dented piece of metal sitting in my garage.

Maybe you know something I don't.

[SJMC_DON]

I have a FMF Power Bomb header and FMF Q2 on my 07. Both pieces were manufactured for an 06' YZF.

The header will fit to the cylinder on your WR just fine... what will be different is the diameter of the pipe to header fitment... the 06' YZF was a larger diameter than other years.... it was not easy cause I got a "good deal" on the Q2 pipe and then I found out I was limited to headers for the 06' YZF and finding a power bomb for an 06' YZF was not easy:banghead:

Another note... I don't what kind of riding you do but I am totally done with Ti headers... Stainless steel all the way for me, Ti dents way to easy!

You don't have to change cams to benefit from an exhaust upgrade, although it will boost performance. I would search the threads in this forum on YZ cams... I found that the 06' YZF cams did not work well with my 07' WR as it relates to e-start, it has a lot to do with the de-comp pin on the YZ exh cam... performance gains are awesome but you are sacrificing the e-start in most cases. I would suggest hotcams specifically designed for the WR...

[SJMC_DON]

What are you hoping to gain with the header? I tried the header approach and got nothing but a dented piece of metal sitting in my garage.

Maybe you know something I don't.

You can gain power anywhere you want with a header and proper jetting... did you get the MX or SX? A powerbomb header can also decrease noise levels by 2 db:thumbsup:

I hear on the Ti thing... luckily FMF makes the Powerbomb in stainless:ride:

[sleddog]

I like the powerbomb design (esp. if I can still use the heat-shield) and if it can cut sound and give a little more bottom end, but the Ti factor is something to consider... If I can find a cheap YZ header maybe I'll give that a try first.

I thought the 08/09 YZ headers were larger diameter (due to restrictive endpipe/muffler)? I'm not sure I want to go too large and lose bottom end. Are YZ 06/07 same diameter? I've been digging around and can't find definitive answers - I wish someone could give measurements for each pipe.

Thanks for the cam advice. Would it be possible to modify the stock YZ decompression pin (anyway to re-use the WR pin?), or maybe use the hotcams exhaust and stock YZ intake? I thought WR's only had a different ex cam compared to the YZ, but I'm hearing both intake/exhaust are now different. Would just the exhaust or intake give them most improvement? I'll probably do both at once since I don't want to pull it apart 2x's.

Also, is a higher compression piston worthwhile (I don't want to run racegas). I mostly ride trails, but occasionally go to the dunes and desert so a little extra power would be nice.

I recently purchased this bike used, and it does ok, but I'm a little disappointed with the power, but I love the e-start and lights (I might try dual-sport someday). I have a friend with an 03 YZ450 - he says it's the most powerful YZ and they've been de-tuning them since, and after a short ride on a KTM 525, the WR feels like it's struggling. The previous owner had someone do all the mods (AIS, airbox, slip-on pipe, jetting, accel pump) and he said the gray wire was left in, but I just checked and it's been disconnected so I'm looking for other mods to try. Back when the 03 WR450 first appeared, a friend did the YZ mods to it and it easily outran a 03 CRF450, so I know there's some potential...

[SJMC_DON]

I used the TT parts store and searched the FMF p/n's for YZ 's and WR's to find compatability... from what I saw, the 06' YZ stands alone in the sizing and you can try to call FMF but they were not much help when I called them... I also tried to find a stock YZ header cheap but there were none to be found... it was easier to order the powerbomb stainless.. FMF sells a heat shield for the powerbomb but after having them on two WR's now, I have not seen the need for a heat shield.

I am no mechanical genius but I think it's a safe assumption that modifying the de-comp pin on the YZ cam might not be possible.

I did speak with one of our local engine builders a while ago and he said the hot ticket was a hi-comp piston and YZ INTAKE cam only, (leave the WR exh cam in)... I can only assume race fuel would be req'd with the piston.

[klossWR450]

this DELKEVIC looks exactly as genuine Yamaha header off '06 YZ450, I have one fitted on '07 WR with FMF Ti Powercore, I have not noticed any power gains really but I think it made the offensively loud bike slightly quieter, while still not quite as a lullaby it is bearable to the neighbours now

[SJMC_DON]

this DELKEVIC looks exactly as genuine Yamaha header off '06 YZ450, I have one fitted on '07 WR with FMF Ti Powercore, I have not noticed any power gains really but I think it made the offensively loud bike slightly quieter, while still not quite as a lullaby it is bearable to the neighbours now

Yes the OEM 06' YZF header in Europe, Australia, NZ was that type, I would have liked to get my hands on one of those... In the US, the 06' YZ header was your standard constant diameter Ti header.

You guys get all the good stuff!

[Just_a_trail_rider]

You can gain power anywhere you want with a header and proper jetting... did you get the MX or SX? A powerbomb header can also decrease noise levels by 2 db:thumbsup:

I hear on the Ti thing... luckily FMF makes the Powerbomb in stainless:ride:

Well, I don't know that I ride well enough to tell too much difference. I added the factory 4 pipe and I got more power everywhere, although I rarely if ever rev that bike really high. (i have a 2 stroke for that). I'm just not that good.

Regarding the noise level, the factory 4 pipe is just friggin obnoxious, no matter what you do. I couldnt determine a 2db drop.

[450_02]

i got a 2002 450 an i cracked my header so im wondering will the 2003 header fit what years will fit that will bolt up right the bends are different and the stock header is longer so if i go after market will i have to get a mid pip an what full exhaust systems will fit what years also are the 2003 the same bend and bolts line up?thanks i wanna get a full exhaust system but i dont know what years will bolt up:foul: