What happens when you remove the fiberglass?

[wolfmangk]

Hello, I just got a spark arrestor for my 1979 RM 250, and to get it on I had to grind the weld that holds the fiberglass and remove the fiberglass/ perforated length from the muffler. What does the fiberglass do? Does it just make the pipe quieter, or does it have any benefits as to performance? Does anyone know?

 

[dell30rb]

It makes the bike WAYYY louder, and dosent improve preformance. You need to have that in there

 

[125 rider]

Your bike will be louder and will have less power due to turbulence in the muffler.

 

[wolfmangk]

Alright, I put some wall insulation fiberglass (NEW) in it and slapped the sucker back in there. Thanks for the replies. By the way, the muffler was welded shot from both ends, I don't think they wanted me to ever replace the packing. Is that way my bike was so loud?

 

[David Trustrum]

’79 was in a place long ago far away, who knows what they were thinking? Probably –“hey lets sell a lot of these things really cheap”.