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NorthernMNSurf

05 YZ450F exhaust help please!

8 posts in this topic

I recently purchased the bike as a project, and am close to getting it tuned properly. But I first noticed smoke at the clamp, then on another occasion the header actually shot off the bike when It was on the "stand". I ordered akrapovic springs, installed them and right after noticed a considerable amount of smoke (there was some black shiny oil residue on the fitting - is that something I should be more concerned about? Most likely cause of white smoke?)

ImageUploadedByThumper Talk1460508551.676623.jpg

I shut the bike off immediately and removed the exhaust. I knew the clamp was no good, bc the plastic in the locking threads had melted. I also figured there should be a gasket somewhere, and the absence of a flange on the header pipe was concerning. Maybe the pipe was cut to fit and not flanged?

I came up with the following: (but could use some direction!)

-no gaskets

-improper mounting screw(s) to top end (pic w rag is of threaded rod inserted on starboard side)

-old/bad packing

-improper clamp

-mix/match incompatibility (black pipe)

I have new packing, will get new screws for header mounting (stainless ok?), and will order the gaskets but am not sure if they will fit this piece meal system. The cap reads: MZ-0023 SCREEN-TYPE, anyone know if the oval shape is generic and if a quiet core would fit something like this?

The header looks ti to me, and possibly the muffler due to the blued welds, but obviously not the black mid? The black pipe has spring loops on the muffler side, but not on the clamp side...stock? I assume the muffler is from MUZZY due to the faint sticker on the exhaust, but no other identification. Anyone recognize the header or mid? Any thoughts on how to proceed?

Pics below:

ImageUploadedByThumper Talk1460506854.133653.jpgImageUploadedByThumper Talk1460506887.066668.jpgImageUploadedByThumper Talk1460506953.873969.jpg

ImageUploadedByThumper Talk1460507708.505123.jpg

ImageUploadedByThumper Talk1460507756.742038.jpgImageUploadedByThumper Talk1460507788.843859.jpgImageUploadedByThumper Talk1460507885.684284.jpgImageUploadedByThumper Talk1460507953.993811.jpg

Thank you!

Edited by NorthernMNSurf

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The header flange came off. 

It's not supposed to do that.

It should be permanently attached (welded)

 

Inside the head there should be a copper crush washer for the flange to push against.

 

 

Looks like some form of and aftermarket pipe, but it is thrashed......

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The flange did not break off the pipe.  It was never attached.  The flange bolts into the head, then the header slides into it and is retained by springs that pull between the tabs on the header pipe and the small holes in the flange.  That's an aftermarket setup used by only a few aftermarket pipes.  There should be a crush gasket under the flange in the head. 

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Thank you both for your replies. I figured it was never welded (which is why I was confused), but shouldn't it stay snug with springs? I installed ps1 (80mm) akrapovic springs. (The header shot off the bike with no springs, but had that white smoke issue with springs installed)

Found the crush ring, it was very compressed but otherwise seemed to be in good shape; I will replace it. Any thoughts on if the header/mid pipe connection might accept an oem gasket? Silencing/usfs spark arrestor options on the muffler? Are most oval shaped mufflers a common size/diameter? Any knowledge of Muzzy pipes? I'm having a hard time finding anything online.

Thanks again!

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The flange did not break off the pipe.  It was never attached.  The flange bolts into the head, then the header slides into it and is retained by springs that pull between the tabs on the header pipe and the small holes in the flange.  That's an aftermarket setup used by only a few aftermarket pipes.  There should be a crush gasket under the flange in the head. 

 

 

:facepalm:  missedit

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No, header/muffler joints come in several diameters and configurations. No telling what size yours is.

Most slip jointed aftermarket pipes don't use a gasket.

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Thanks gray,

I ended up using a pipe expander on the mid pipe and swapped the old no-name header for a powerbomb. I was able to make a decent joint and also repacked the muffler for good measure. The bike sounds great, but I'm running into valve timing issues I've recently posted about. Thank you very much for your responses and trusted guidance!

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