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MOTOBRICK MARKETPLACE => FS WTB WTT ~ Bikes ~ Parts ~ Gear => Topic started by: Rcgreaves on October 27, 2018, 09:56:11 PM
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Do I really have to spend $35 plus shipping just to remove and install my muffler system. Will I find these at a NAPA store?
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You can take the muffler off without disturbing the headers. I've never had my headers off so I'll refrain from further comment.
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I guess my choice of words wasn’t sufficiently precise chaos- (an apt handle here sir!!)
Anyway better stated I want to swap the perfect exhaust pipe and muffler from my parts bike on to my daily driver.
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Hey RCG !!! If you're looking to remove JUST the muffler, be advised there's a very thin, INCREDIBLY fragile Mica gasket between muffler and header that is no longer available from anybody. And OF COURSE it has to be in there and apparently muffler tape/muffler patch products fail. The technique I've used is to loosen the clamp and take it off....then slowly oh so slowly twist back and forth while tugging straight backward away from the header.
If you're taking the whole system off, leave it together. To chance destroying that stupid cylindrical gasket with no replacement is not worth it. The copper nuts are reusable, just mind the studs as you loosen them as sometimes the studs come out with the nut. New exhaust gaskets are crush-able and you could try to anneal them, but as new, they are meant to form fit in the port by, well, crushing. TBH, I've reused mine twice and to this day zero leaks.
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Thanks sir. Mica gasket intact. Thanks as always.
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I wonder if carbon fiber tow could be wound around the pipe as a replacement? It could stand the heat...I recall VW beetle J boxes had sealing rings made of this mica material. Asbestos I spose?
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https://www.truevalue.com/gasket-material-non-asbestos-1-16-x-12-x-20-in?ctplacement=647323-44622122499&cid=gooshop&ctcampaign=4680&ctkwd=&ctcreative=44622122499&ctplacement=&ctadpos=1o2&ctmatch=&ctlocid=9018903&cttrgtid=pla-294682000766&ctfeedid=&ctnwk=g&ctdevice=t
1/16 inch thick...Just poking around on the net on a windy sleety day.. This might work cut to shape and rolled round the tube?
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1/16 inch thick...Just poking around on the net on a windy sleety day.. This might work cut to shape and rolled round the tube?
No. The muffler is 2mm (inside dia) larger than the header (outside dia) at that point so what you need would have to be more like 1/32" or 0.75mm.
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Ok thanks.
Maybe a piece of stainless steel shim material shaped would do the trick? 1/32 thick..gone -ape meant it when he stated “fragile above.
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Advance Auto Parts here in the Usa stocks a 3/64” sheet material called Felpro 3009. Rubber fibers with a metallic inner core. Anybody ever try something like this?
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I have some brass gaskets that BoCutter Ed made to replace the fairy dust OEM gasket. They can be had for a donation of $25 to the Motobrick.com which isn't a bad deal. Shipping is free.
Regarding the "copper" nuts. Don't bother. Just get some stainless nuts and use copper anti-seize on them. I also replaced the OEM studs with stainless from McMaster Carr. A few years ago I bought a set of them from MaxBMW and they were magnetic ie. copper plated. That's probably why the nuts I was replacing were rusted onto the studs.
I have reused the copper gaskets at least twice on my bikes with no ill effects. Just do a good job of cleaning the surfaces they seal against. A very small wire cup brush on a drill or Dremel tool works well.
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I have some brass gaskets that BoCutter Ed made to replace the fairy dust OEM gasket. They can be had for a donation of $25 to the Motobrick.com which isn't a bad deal. Shipping is free.
IIRC it was $30 to motobrick and a Non Disclosure with me ...
gasketcutter Ed
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As for the OP's original question about the copper exhaust gaskets, yes they are usually one time use only. They get crushed on installation and conform to the two surfaces - header and exhaust port - to form a leak free seal. Removing the header and replacing it with another will compromise that seal. You may try to reuse the old ones, but you may also find the bike backfires when you are finished. It's best to replace them each time the headers come off. Try NAPA for equivalent parts but BMW is going to be your best choice.
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So my local Menards hardware aisle has M8 stainless nuts for less than a buck but I didn’t know whether I needed 1.0 mm thread or 1.25 as when I searched the Net both sizes appeared as options.
Also, there’s this Promising mica gasket material Called Felpro 3009 its a gasket sheet that I believe meets the thickness and flex requirements to be a suitable replacement for the “unobtainium”based BMW exhaust to muffler mica gasket ring. See the caliper measurement images Ive attached.
Anyway I haven’t purchased my gaskets or nuts or this 3009 sheet, but my goal is to sway in my sweet polished unit from my old bike for a few Johnnie inspired “yeehaahs around Christmas. Stay tuned.
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The exhaust bolts are M8-1.25 (coarse pitch), not M8-1.0 (fine pitch).
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You could try annealing the copper header gaskets by heating to cherry red and quenching in water. Then re torque to proper value.
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So I raised a materials scientist and have some experience fabricating, but what would annealing do to take the compressed shape out of a copper ring. For my part that’s a part you should replace new. Curious nevertheless...
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Yes, new is best, if that is an option. The ring will just compress a bit more. (maybe .001?) I don't think the dimension (thickness) is that critical. This works on copper head gaskets.
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So in my experience thicker gives a tighter seal...I recall my teen years installing intake manifold on a VW beetle with similar copper rings, incomplete seal, lean run..maybe that’s immaterial here on the exhaust side? Are there side effects to a poorly fit exhaust seal?
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Yes, usually air entering exhaust will cause popping,... but these bikes do that anyway. If it is not leaking visibly, I wouldn't worry.
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I have yet to replace the exhaust gaskets on any of the four bricks I've owned and had no issues. Once I learned to close the throttle when coasting almost all the backfarting stopped.
As far as the "copper" nuts, they're just copper plated. How much of that copper plating do you see on the nuts that are there now??? I save lots of my money and use stainless nuts and studs from McMaster Carr