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Rear downpipes stuck when trying to remove headers.


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Hi all, I'm removing the stock exhaust off my 1998 5th gen to install the WiLD headers and can't get the rear downpipes separated.  Do you guys have any tips on how to un-stick these things?  I've tried spraying a bunch of penetrating oil in the joints and pulling on them with towing straps but they won't budge.  Its so tight in there, I can't get good leverage to pull on them or try to twist them.  I have a propane torch, but am wary to use it because of all the plastic nearby.  I'm not opposed to just cutting above the joints, but that seems like a waste of good parts to me and would like to avoid doing that.

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  • Member Contributer

They are pesky little devils, aren't they??  😈 Honda provided a graphite type gasket inside those joints that is relatively easy to slip apart unless the metal is corroded.  Your '98 headers are mild steel, so if your bike has seen a lot of rain or is near the ocean, etc that could be an issue.  Age is also not your friend in that situation as mild steel will rust over time.  Even with the new VFRD headers I found that those joints must be lined up - in other words, the tubes must be in a straight line to each other to separate.  If they're in a bind, you'll have a very hard time getting them apart.  It's also compounded by there being two that need to be lined up and separate simultaneously.

 

A second set of hands wouldn't hurt to hold the main part of the headers under the bike in such a way that you can get the alignment you want.  In my case I put some wooden blocks under them since I was working alone.  I used a rubber mallet to help persuade them - patience is going to come in to play - it's not particularly easy.  Try having a helper hold the headers while you grasp the shorter tube and rock it back and forth / rotate it to try to work it loose.  If you cannot rotate it at all it's probably not going to slip apart until it does.  You might want to wrap a towel around your swingarm, as banging the headers around can cause some scratching if that's a concern.   I would resist the urge to get the sawzall going - your OEM headers have value to owners who didn't go for the aftermarket headers, but do need replacements due to age and rust.  Sounds like you've got plenty of help in the form of penetrating oil, so some persistence should get them apart. 

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PB-Blaster is oil to use, much, much better than anything else, Spray on liberally, let sit overnight,  and you may find your header-pipes laying on ground in morning.

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That's what I used.  I sprayed a bunch to loosen the clamps as well, so there is a good amount of PB-Blaster in the joint already.  I'm a big believer in PB-Blaster.  First time using it was on an f4i rear master pushrod (also going on this bike), the locknut was basically seized to the brake rod joint and I was starting to round the corners on it.  Let it sit overnight in PB-Blaster and it basically came right apart.  Now I spray it on every stubborn fastener before trying to really lean on the wrench.

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Make a shield for the shock & use a blow torch to heat the lower pipe socket & wiggle at the same time. Try not to burn anything else. 

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Move the flange to the joint with a little bit of play, take the joint clamp off and replace it above the flange so it can't move back and then wedge something between the flange and joint to separate 

downpipes.jpg

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Well, I finally got the headers off this evening.  I ended up just trying to twist them using towing straps (I was pulling vertically before) and that seemed to break it free.  It still took quite an effort to get the two downpipes off after that (another hour or so) but the job is done.  I ended up having to remove the right side rearset by removing the swingarm nut to give better access to the header pipes. 

 

One trick I did was to put the hook of the towing strap into the header opening and wrap the strap around my shoulders so that I could pull vertically on the downpipe while pushing down on the collector with my foot.  This seemed to deform the graphite gasket enough so that the downpipe could start to slide out with a lot of forceful wiggling.  I think the takeaway here is that you won't be able to pull the downpipe straight out, you'll need to deform the gasket to make room for it to be wiggled out.  I actually had a similar problem with removing the muffler on my 58k mile bike, and unfortunately this also means that the gasket will be destroyed and you'll have to replace it.

 

Thanks for the help everyone.  One more question for you guys.  Should I replace the exhaust studs and bolts with new ones or just slap the old ones back in there with the WiLD headers?  All of them came off easily enough, but the studs have some moderate surface rust.

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Nice!  Good that you got 'em.  

 

I reused both the studs and nuts , tho they were rust free.  I did however double nut all the studs to remove them  - then before reinstalling used nickle anti-seize on them for future removal.  There's almost nothing worse than one of those things breaking off in the head and then figuring out some way to get it out.

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It appears to just be surface rust, but I took a few pictures.  First one is as I found it, and second one is after using a brass brush with WD-40.  All the other studs look about the same.  Looks usable to me, I'll probably just use 'em.  For some reason though the nuts on the #2 cylinder were different, I guess just another clue to this bike's past.  The other nuts looked alright and probably just need a quick clean.

 

header-stud-before.jpg

header-stud-after.jpg

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I would always go new , especially as you have done all the hard work and are there anyway. A stud extractor makes easy work of it. 

However , If you are going to re-use them , run a die over the studs and a tap on the nuts to really clean up the threads and don't forget your copper ease. 

 

 

1799076275_EXHAUSTSTUDS.thumb.jpg.7ef7e38c5bc8e4a49e25e73f67ffc6ee.jpg

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  • 2 weeks later...

Well everyone, I pulled the studs two weekends ago and they were a little crunchy when spinning the nuts on and off.  As soon as I felt that I knew I had to replace them.  I ordered them online and now the distributor says that they are on backorder with no ETA.  Sounds like everyone that got the WiLD headers went out and bought all the VFR exhaust studs in stock!  I tried to cross reference similar Honda parts, but didn't come up with anything (all the CBRs use M8s).  If I really have to I can get some 18-8 stainless fully threaded studs and use those.

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FYI, eBay over here (UK) has M6 stainless exhaust studs--proper ones, not just all-thread.  At least, that's where I got mine years ago.

 

Ciao,

 

JZH

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Well, looks like I may have just been a little impatient because the order shipped yesterday.  I admit I've been a little jumpy lately with parts availability, and also I have a trackday next month that I'd like to take this bike to.  

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