Powerbomb w/ stock silencer on WR426?


3 replies to this topic
  • NuckingFuts

Posted February 18, 2005 - 06:08 PM

#1

I just picked this bike up (2002 WR426) and it already has a powerbomb header (dont know if is an MX or SX....maybe you guys can help me ID it) with the stock silencer (which has a GYT-R insert).

Do you think this is a sufficient set-up for power gain......so much that it would be a waist of money to get some other silencer? In other words, would my money be best spent elsewhere?

So far I know it has:
YZ timed
Re-jetted (feels spot on)
Not sure if it has the Power now (or James Now) but Im going to pull the carb this weekend and find out.



As a side question: Have you noticed odd chain wear on this bike? My links are worn on the top and bottom sides so much that its flat instead of "figure-8" shaped (bike only has 400 miles)......hope you can visualize that. :)

  • yamaha-er

Posted February 18, 2005 - 08:12 PM

#2

I have the same bike with a Powerbomb header and YZ exhaust with a PMB insert. A little power increase with header but not much over stock. The biggest increase was from rejetting using a 2003 YZ250F needle. I would get an adjustable fuel screw and either try a 250F needle on the fourth clip or James Dean needle kit. The carb will need to be cleaned out ever so often, I was shocked the first time I took the carb apart, all kinds of sludge in there. It gets real expensive trying to add more power after those mods, like 450 kits.

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  • unkle_george

Posted February 18, 2005 - 09:21 PM

#3

As a side question: Have you noticed odd chain wear on this bike? My links are worn on the top and bottom sides so much that its flat instead of "figure-8" shaped (bike only has 400 miles)......hope you can visualize that.



If it rubs alot of gritty diry or sand on the chain guide I can see it wearing down. Mine is at least nice and shiney.
Check that your sliders aren't worn where the chain is rubbing on metal. (UFO chain sliders are junk BTW)

- Ryan

  • NuckingFuts

Posted February 18, 2005 - 09:37 PM

#4

Yeah, Im going to try and find out more info on what carb components were used. So far I know that there's a #170 main and the clip is on 4th down but I have yet to pull the carb to see what other size jets the last guy ran......and what needle for that matter. I do know that the jetting is great right now, may not be giving all the ponies possible but at least its smooth.

BTW, do you know were to dig up a pic of the WR needle and the YZ needle?
Im told the YZ needle is quite different (multi-taper) so it would at least help me I.D. what I have so far.


Other than that I just need to rig up a heat shield to the powerbomb.




 
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