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Muffler re-pack for an old carbon fiber can ?

yzsofst

yzsofst

Active member
Joined
Feb 9, 2003
Location
Roseville
Moto(s)
Honda 919, Yamaha YZF600r, Yamaha FZ1, Honda CRF300L
Hi guys,

I've got a Yosh carbon pipe on my FZ-1. I've got the repack kit from Yosh on order and just watched their video. Seems straight forward. Punch, drill, pull apart, re-pack, rivet and install.

Here is my question. I bought the bike used. It's a 2007. For all I know this can is over 11 years old. The idea of hitting a punch with a hammer has me worried that I'll crack the pipe somewhere. Stainless steel, sure. But old carbon fiber? Would I be better off skipping the punch/hammer and attempting to drill it out entirely? This would probably take longer but could save me a $500 f-up.

Or, am I not giving carbon fiber enough credit? Strong enough to take the hits, no worries, use the punch?

Thanks!
 
Just drill out the rivets , 1/8" drill bit . Drill em all , remove canister . R&R packing . Re-rivet .
Done .


oh yeah , wear gloves and an old cotton sweat shirt .
 
I'll second the drill out method. I never used a punch, always drill. Punching is NOT the correct or prescribed method. Youtube fail. :laughing :thumbdown
 
The only reason to use a punch before you drill is to get a mark of where to drill.

The rivets that I've seen on exhausts generally already have a recess in the middle, perfect for centering the drill. No reason to punch them before drilling.
 
If the current rivets are stainless steel, buy a hardened drill bit or you'll use up a few bits getting them all drilled out. If they're aluminum, no problem.

Actually, I can tell when it's time to repack the muffler on my thumper because all of the aluminum rivets start melting. Less drilling to do. :laughing
 
Thanks guys. Time to go get a rivet gun and a hardened bit.:thumbup
 
be really careful.
exhaust gasses will eat CF from the inside out if they come in contact. if it's never been repacked, i'd expect some damage to the inside that may not be obvious from the outside and it'll be fairly fragile in those areas.

you have nothing to lose if you damage it btw, because eventually it'll break there anyway. some CF slipons are a CF shell over a really thin aluminum tube to avoid this, no idea if yosh does this or not.
 
auntiebling said:
be really careful.
exhaust gasses will eat CF from the inside out if they come in contact. if it's never been repacked, i'd expect some damage to the inside that may not be obvious from the outside and it'll be fairly fragile in those areas.

you have nothing to lose if you damage it btw, because eventually it'll break there anyway. some CF slipons are a CF shell over a really thin aluminum tube to avoid this, no idea if yosh does this or not.
Click to expand...

Man, that's a huge potential bummer. Wish me luck. Guess I'll really take my time with the drilling. Seems like getting the can apart can take some elbow grease too. Another potential pitfall. If it does break, I'm replacing with aluminum for sure.
 
Punching the center part of the rivet isn't that big a deal. It makes it easier to drill. However, I wouldn't do it on a carbon fiber can. And if you do use the punch, make sure that it's not tapered and is small enough to fit loosely inside the head of the rivet. The idea is to drive the inner part out, not apply any force to the rivet itself.

Pay particular attention to the rivet material. Replace with same. I made that mistake years ago with a BUB can on my old Suzuki. I repacked the can and reassembled it with aluminum rivets. I then made a trip down to San Diego and back on a three day weekend. When I rode into my driveway late Sunday night and parked the bike in the garage, I noticed the inner tube with all the louvers and the large flange that's attached to it hanging out of the back of the muffler about half way. If I'd rode any further, I'd have lost it. Turns out the aluminum rivets weren't up to the vibrations and had self destructed. I replaced them with SS rivets and all was good.
 
ST Guy said:
Pay particular attention to the rivet material. Replace with same. I made that mistake years ago with a BUB can on my old Suzuki. I repacked the can and reassembled it with aluminum rivets. I then made a trip down to San Diego and back on a three day weekend. When I rode into my driveway late Sunday night and parked the bike in the garage, I noticed the inner tube with all the louvers and the large flange that's attached to it hanging out of the back of the muffler about half way. If I'd rode any further, I'd have lost it. Turns out the aluminum rivets weren't up to the vibrations and had self destructed. I replaced them with SS rivets and all was good.
Click to expand...

Funny you mentioned that. My local Lowes only had aluminum rivets... I thought I'd try them out and see how they worked... When you replaced with steel did you open it up to get the aluminum bits out or just leave the little pieces in there?
 
Cobalt drill bit is the preferred option for drilling into harder steel as well as stainless steel grades.

BTW since CF is conductive corrosion can be an issue. Carbon-fiber composites may corrode galvanically if aluminum fasteners are used due to the chemical reaction of the aluminum with the carbon fibers. Because mufflers heat cycle, condensation of water can provide an electrolytic condition ripe for corrosion. Coating the rivets with a dielectric can guard against corrosion. I'd opt for SS rivets with as wide a flange as available to mitigate damage to the CF. :2cents
 
yzsofst said:
Funny you mentioned that. My local Lowes only had aluminum rivets... I thought I'd try them out and see how they worked... When you replaced with steel did you open it up to get the aluminum bits out or just leave the little pieces in there?
Click to expand...

Find out what the original rivet material is. One way is with a sharp blade. You'll be able to shave off bits of aluminum. With SS you really can't. A razor blade can be used.

Once you drill them out, assuming you use the correct size drill, all pieces of the old rivets should come out.
 
yzsofst said:
Funny you mentioned that. My local Lowes only had aluminum rivets... I thought I'd try them out and see how they worked... When you replaced with steel did you open it up to get the aluminum bits out or just leave the little pieces in there?
Click to expand...
I wouldn't worry about the bits
 
To find out what the rivet material is simply contact Yoshi, they will gladly tell you as well and give you the best info on repacking the can. It avoids all the guessing.

Also, Yoshi has a refurb service for anything they make or have made. They can take trashed exhausts and return them to as new condition. Often, owners of bikes for which exhausts are no longer made want their repaired and Yoshi will do that for their own brand.

Here: http://www.yoshimura-rd.com/contact_us.asp

Many of the people working there have been there for a long time. They take pride in their work and stand behind their products. If anyone knows how best to deal with your situation they do.
 
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