Header choice: MB vs. PB


5 replies to this topic
  • oldmanx

Posted December 25, 2008 - 02:08 PM

#1

For Christmas, my son surprised me with a FMF Q4 for my 04 WR450. :busted: That has me thinking about also changing out the header. I ride mostly woods and trails. From what I see, it looks like the FMF Megabomb is a better low to mid-range power producer than the Powerbomb. Is that correct?

I've also been thinking of swapping in a Stage1 exhaust cam for improved bottom end. Will this upgrade affect my header choice?

I did search the forum first...saw a lot of YZ vs. PB header info/debates. That's not what I asking here...just MB vs. PB comparisons.

  • qwik12beat

Posted December 25, 2008 - 06:41 PM

#2

The megabomb is a very good pipe to run with the Q4.It will work better than the powerbomb. I think you would be very happy with that combo. The cam would just be the icing on the cake. The low and mid from the megabomb is awesome,better than the powerbomb.:busted:

  • KJ790

Posted December 25, 2008 - 06:52 PM

#3

I've run the SX powerbomb, MX powerbomb, factory forward powerbomb, and a megabomb on my 450 to see how each one felt (I'm not even sure it all three powerbombs are still sold, I think the MX powerbomb was discontinued). The FF powerbomb and SX powerbomb are the same performance, just one centralizes mass better. The MX powerbomb adds up top, and doesn't really touch the bottom. The SX powerbomb did the opposite, adding to the bottom with little to no change at wide open. The megabomb felt like the SX powerbomb except with a tad more on the bottom, hardly even noticeable for me. Best bang for the buck is a stainless SX powerbomb since it feels close to a megabomb but is $150 less.

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  • oldmanx

Posted December 26, 2008 - 07:25 AM

#4

I've run the SX powerbomb, MX powerbomb, factory forward powerbomb, and a megabomb on my 450 to see how each one felt (I'm not even sure it all three powerbombs are still sold, I think the MX powerbomb was discontinued). The FF powerbomb and SX powerbomb are the same performance, just one centralizes mass better. The MX powerbomb adds up top, and doesn't really touch the bottom. The SX powerbomb did the opposite, adding to the bottom with little to no change at wide open. The megabomb felt like the SX powerbomb except with a tad more on the bottom, hardly even noticeable for me. Best bang for the buck is a stainless SX powerbomb since it feels close to a megabomb but is $150 less.


Thanks for the info!! I work p/t at a local bike shop that happens to be a PU dealer. I checked inventory and there is a very limited # of all 3 styles of PB's and the MB still available. Based on you info, I'll be ordering the SX PB when I go to work tomorrow.

Might you have any input on my cam question?

  • KJ790

Posted December 26, 2008 - 08:13 AM

#5

Thanks for the info!! I work p/t at a local bike shop that happens to be a PU dealer. I checked inventory and there is a very limited # of all 3 styles of PB's and the MB still available. Based on you info, I'll be ordering the SX PB when I go to work tomorrow.

Might you have any input on my cam question?


I haven't run any hotcams on my 450 yet, though I would like to some day. I do run them in my 250F. The problem is, stage 1 hotcams for the 250F add low end power, and stage 2 add top end, but this isn't true for the 450. Up until about a month ago all that you could get for the 450 was a stage 1, and looking at the dyno graphs, it doesn't affect the bottom end at all vs. stock YZcams. Puting them in a WR will help the bottom end due to the hotcams having the YZ timing. They now introdced the stage 2 cams, but the exhaust cam will not work in the WR because they do not offer it with the correct length decompression pin for electric start. Here is the dyno of stock YZ cams to stage 1 hotcams:

Posted Image

  • oldmanx

Posted December 26, 2008 - 08:55 AM

#6

Thanks KJ. It looks like I should save the cam money for the 450. I sure do not want to lose my e-start ability. Or maybe use it for S1 cams for my son's yz250f...like he's been bugging me for.




 
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