Crimped head pipe!

9 replies to this topic
  • tnl

Posted March 12, 2005 - 06:33 PM


My 05 450 has a significant crimp in the bend of the head pipe. It's crimped at the center of the bend and also at the frame. Looks as though they crimped/bent the pipe more than they needed to fit it by the frame? The head pipe is bent in about 35% of the diameter. I looked at some new WR's (because no 450's were in stock) and there not bent at all at the head pipe radius??? Any comments?

  • mxracer452

Posted March 12, 2005 - 10:17 PM


my 03 never had a crimp in the head pipe anywhere....and from the pics i've seen it doesn't look like there should be on the 05's either....i would check into getting a new's the link to the pics i looked at...take a look for urself... http://www.yamaha-mo...aha_yz450f.aspx

  • grayracer513

Posted March 12, 2005 - 10:22 PM


If you mean that the cross section of the pipe is more oval than round, I would say that was a defect. Getting someone at the dealer to agree with you may be more difficult.

  • 35yz450F

Posted March 13, 2005 - 08:32 AM


Mine bent exactly as you described from a low side crash in soft dirt. It took me a couple of weeks to notice. The pipe bent upward crimping it in to and oval at the bend putting the pipe about a 10mm from the radiator. I bent it back while the bike was running, but its not round anymore. While it was kinked the bike wouldn't rev very well. I have a new header on the way.

  • tnl

Posted March 13, 2005 - 02:01 PM


Coming out of the cylinder the pipe is bent on the interior of the radius section. Cant be from a crash because of the location of the bend? I'll take a picture and post it for more help!

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  • mxracer452

Posted March 14, 2005 - 12:47 PM


if its crimped where your arrow is in the pic then it could be from a crash....but i would think there would be some kind of dent in the pipe where it may be a defect in the pipe.

  • MotoGoalie

Posted March 14, 2005 - 01:08 PM


Hmmmm. I bought my 450 used but I have notice there are two decent sized dents in my header. One that 1rst curve about the size of a quarter and probably a .25 inch or less indented and the other about 3 inches from there, similar size.

Do you guys think that would affect performance? I just got the bike so I dont know what to expect....I was planning on putting a powerbomb at some point....should I do that sooner rather than later?

  • tnl

Posted March 14, 2005 - 03:13 PM


The irregular shape of the pipe (not a dent) that exists in the head pipe is at the side closest to the cylinder head and has no impact marks that you would see if it were from a crash. I think it is impossible to blame a crash (which i have done) on that mark on the pipe because it is on the side closest to the cylinder of the pipe. If you were to bend a straight piece of garden hose to to match the head pipe shape it would bend or kink just as my pipe is and in the same location? It definitely will reduce engine performance. Wasn't sure if that's what you get with a stock set up? Check out this site. The dented head pipe looks kinda like mine...Maybe it is from a crash :)

  • 35yz450F

Posted March 14, 2005 - 03:55 PM


You crashed and bent the header up.

  • smokin529

Posted March 14, 2005 - 08:48 PM


I bent mine the same way just by laying it over in soft dirt too...didn't even leave a mark on the outside of the pipe. Titanium does weird things when it gets hot. I race mine in the woods and switched to a stainless steel FMF powerbomb header and haven't had a problem since. The stainless weighs more but doesn't get nearly as soft when it gets hot. FMF's header also tucks in a little better.

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