[lrutt]

I have FBF hi carbons on my M900. They probably have only about 2500 miles on them. I noticed over the last 500 miles or so that there were a couple area's on the CF right at the inlet that was starting to 'char' like it was gettin hot, and that there were signs of exhaust escaping around the can at the inlet. On an FBF can you can take it apart by removing just 3 screws, so I tightned them up some thinking they were loose. Problem persisted.

Last weekend I got a wild hair and just took one of the cans off and tore it down. What I found is that the fiberglass packing in the front half (inlet half) of the pipe was pretty much burned out. Reason being as the hot gases come into the can they tend to want to travel in a straight line so as they enter the perforated core the gases just burned out all the packing on the whole top side of the can for about 6". Both sides were like this.

How to fix? Well, I purchased some metal foil tape and taped the leading 6" of the perforated core to prevent the gases from hitting the packing directly. I also repacked with heavy fiber glass matt instead of the wool type material. I've used matting before with excellent results. Re-assembled and seems to work great. A side benefit is a nice change and slight increase in the sound level. I was looking for that anyhow.

Anyhow, purpose of this post was just to kind of let people know of that condition. I'm sure FBF cans aren't the only ones susceptible to this as all highmounts in particular will have the fairly drastic change in direction of the gas flows which lead to this problem. I know on my cans the leading portion on top would definately be too hot to touch while the rest of the can was just warm. Now, the entire can only get's just warm.

Fortunately I made the correction before there was any real visible damage to the CF. Total cost was about $25 for the whole job.

 

[wheelinman900]

Re: Something interesting about Hi pipes in genera

Wow thanks for that information. I think sil moto makes those pipes right? I have sils on my bike so I'll keep an eye out for it. I think its real cool when you can take a pipe all the way apart. Every pipe should be made like that.

-Patrick

 

[Andrew_Cornett]

Re: Something interesting about Hi pipes in genera

All CF pipes should be repacked every now and then just for the reason that you discribed.

 

[lrutt]

Re: Something interesting about Hi pipes in genera

I realize they should, but at less than 3k miles ???

 

[s4strati]

Re: Something interesting about Hi pipes in genera

another idea would be to apply the foil tape to the inside of the carbon sleeve. would reflect heat back into the can rather than onto the sleeve itself. but yep... as mentioned, all cans should be repacked as routine maintainance. surprising your packing got blown out so early though. good workaround taping a portion of the perf-tubing.

another suggestion if you wanted a virtually permanent solution would be to wrap the perf-tubing with header-wrap and not bother with packing at all. but with how much denser header-wrap is than muffler packing, you'd lose some backpressure and the cans would be MUCH louder.

 

[lrutt]

Re: Something interesting about Hi pipes in genera

Short of straight pipes, I don't think it could get too loud. That crossover below has to break it up quite a bit. I know I run baffles in my Harley and that's just right, can't stand straight pipes on those twins.

The header wrap sounds interesting. I think I'll find and stock some of that for possible future maintenance.

What exactly is header wrap made of. I've seen it but not sure. Is it asbestos based??