Muffler Dents-Performance

I want to get a cheaper used FMF exhaust for my bike. The one on eBay I was looking at had some dents in it. Do dents in the muffler have a big impact on the performance? Also the pipe looks to be turned the wrong way does that rotate? I don't want to buy this if the pipe will not rotate because I think it looks like its turned the wrong way and wouldn't fit.

s-l500.jpg

dents like that mean nothing

Dents are OK.

Mufflers are not universal. That tail pipe must be once designed for your bike. Most of therm are held in with springs. You will probably need an appropriately sized head pipe as well. Most after market pipes are larger diameter than OEM.

1 hour ago, William1 said:

Dents are OK.

Mufflers are not universal. That tail pipe must be once designed for your bike. Most of therm are held in with springs. You will probably need an appropriately sized head pipe as well. Most after market pipes are larger diameter than OEM.

On eBay, the guy listed it for my bike and the year. I just purchased an FMF mega bomb and it should fit, but the pipe coming out of the muffler in the picture looks like it's been rotated. You can see the mount welded on the pipe but it is facing down and it should be facing the same way as the mount on the muffler itself.

 

No, it doesn't rotate, it's welded solid. The dents won't make any difference, but if it doesn't fit, it doesn't fit.

What is the sellers feedback %? Even though the dents won't effect performance, that thing is a beat up piece of junk at best..

The exhaust gasses flow through a perforated tube on the inside and are surrounded by fiber glass packing. Those dents won't hurt performance at all.  

1 hour ago, OLHILLBILLY said:

No, it doesn't rotate, it's welded solid. The dents won't make any difference, but if it doesn't fit, it doesn't fit.

What is the sellers feedback %? Even though the dents won't effect performance, that thing is a beat up piece of junk at best..

https://www.ebay.com/itm/FMF-EXHAUST-MUFFLER-PIPE-CRF250X-CRF-250-X-CRF-250X-2004-2005-2006-2007-2018/302490843608?hash=item466ddbf9d8:g:6IQAAOSwiAlZ5SVZ:sc:USPSPriority!06033!US!-1&vxp=mtr 

 

the sellers feedback is good. It doesn't look like it would fit any bike. I will probably just keep looking.

$156 is waaay too much for something that beat up. Maybe if it was in pristine condition and obviously would fit.

That pipe is worth a case of beer and nothing more. 

18 minutes ago, BoxcarWilly said:

That pipe is worth a case of beer and nothing more. 

Yup, and it better be cheap beer. That is a $30 muffler.

Welded pipe no rotating anything.   Dents are not critical, clean core and good packing is critical if you want a muffling muffler.  So per your statement not the correct one, but keep in mind there are stock tip replacements and aftermarket systems which are not necessarily the same.   Look up specs for your setup.

 

     As for dents. Consider being ready with repacking material,  you drill out rivet heads on the end cap to open and service with a drill bit just bigger than the riviet shaft. The bit centers itself in the hole and once you reach the shaft a ring will run up your bit, be prepared to stop drilling asap..  I either thread the cap or install rivet Nuts if not so equipped to allow for future hand tool removal.   While open you can slap the dent out from the inside with a long thin  steel tool.  If the core is removable a blue flame from a map gas torch will burn off carbon which will knock off or brush off once cooked. 

 

     While open, and it is a good reason to prepare the first time consider a spark arrester Tip if it does not have one.  Otherwise the Forrest Service will tell you to push it to the trailer.   BTW Rangers are the best, tickets left on the truck for Forest use without a pass are payment forms for the single day you stole, or normal annual pass fee which they mail to you.  The ranger is your friend and is good to stop and ask questions as they know the condition or availability of trails and have a helpful attitude by trade.  If it is dry they might poke a metal rod in to see if you have a spark screen or as suggested a decibel meter if you are insane loud not having repacked the muffler.

 

     For dents you can not reach it is time to weld a tack stick and use a dent puller. or drill a hole and screw dent pull but only if you are a competent sheet metal welder or the holes will only get bigger. 

 

If it was a big old gunked up 2 stroke exhaust, especially a boxy Street type with internal baffles which clog and no access.  The correct procedure to service is called De-carbonizing. You cut 3 lines to form a door and hinge it open.  Burn out all the oily crap with a low flame, shut it and weld the door gap.  With an expansion chamber not necessary. 

Edited by Fred X
That pipe is worth a case of beer and nothing more. 

Better just be a case of natty lights. It isn’t worth the expensive stuff.

 

The E-bay pipe DOES rotate , but it's not worth the price. New is only twice that.

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