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replacing headers with crossover for ones without


d1jezek

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I didn't find my particular question answered here so I started a new topic.  I've got the '04 LeMans.  Mine is a sport/naked and it has the troublesome crossover.  I've had the shims replaced with stainless, I've had cracks rewelded and now I'm just giving up and replacing with earlier header pipes that don't have the crossover. Got them and the crush gaskets from Harper's, who advised me to just reuse the sensors because they're stupid expensive.  When they arrived I went to start the job and found that the flanges seem captive on the header.  I actually put everything back and ordered some different ones. I have them now. The diameter is greater than the headers to the point they'd rattle.  Did I not notice some kind of insert in the flanges that I could have removed, thereby freeing them? I don't see them in the exploded parts diagram but that doesn't mean they don't exist.  I don't think I misordered the flanges, and they're billet and fresher looking so I want to use them.  I just want to know if i still need some parts or if I just didn't notice the ones that are already there because I wasn't looking for them.  Save me from another disassemble/reassemble just to find out.

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the two new headers are different from each other.  one is 7/8 shorter at the engine end and there's nothing to stop the flange.  the other has a different end and the flange has something to snug up against like what i saw on the header that's currently on the bike. i took pictures but i can't figure out how to get them into a reply here.

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even in the parts list for the year these headers are used doesn't show anything i shouldn't have already.  maybe the left and right header are just different in ways that will become clear as i go along.  i'm just going to have to take it all apart again and see if that's what happens.

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what i think i have now is one wrong header. the one that should fit on the right doesn't have the correct diameter at the largest point. my current flanges are indeed trapped on the headers. there is no way past the engine end of the header, nor the crossover. so the new flanges are necessary. either i need a different header entirely on the right, or there's some kind of split insert that fits around the end of the new header and inside the flange.

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going back further to the parts list for the 2000 model gave me the diagram where part number 4 is the spacer Lucky Phil is probably trying to hip me to.  i guess i need a couple of those, but only on one side.  there must have been some other changes to these pipes and one of the ones i got is later than the other.

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Here is an early pipe and one from my 2003 LeMans. The early ones take two half-circle spacers and have finned flanges. The later ones have captive flanges and do not take spacers. You can see that the spacers, when installed, duplicate the shape of the later pipe.  Another way to think of it is - the later pipe has "built-in" spacers.

 

I had the cross-over holes welded shut. That worked great, but then I found a used set from a 2002 bike - and that's what I have on there now.

 

IMG_5451.jpg

 

I have 5 used pipes that I'd gladly let go: the welded pair, the "early" pair (which I bought by mistake) and one RH 2002 pipe (captive flange and no crossover) - PM sent.

 

 

On the different lengths:  The two pipes are supposed to be different. The LH cylinder sits further back, so the top part of the pipe has to come further back to meet the head. 

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II suspect the shorter pipe goes on the left as that cylinder is set back of the other.

 

Time to have another look at your bike then...  :whistle:

 

If you start at the crossover, the bottoms and the curves are the same, then the LH is longer on the top to reach the cylinder that is further back.

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