Drilling holes in 76-79 standard mufflers

[Shovel Jockey]

I saw a picture of a guys 77D standard the other day. Nice bike, bone stock. I noticed that the upswept stock mufflers had been drilled on the rear of the muffler in the indentations around where the pipe exits. Have any of you tried this? How does it change the sound? Would this work for a stock bike with K&N filters?

 

[rezsst]

i would like to know too. i have a 1980 and would like to hole saw the end of my muffler about 1" dia then if i dont like it i can get a metal tube cap or plug at the hardware store

 

[Royboy]

Study previous threads regarding modifying stock muffs. Lots of info already. Look under "topics" - "exhaust". Many have drilled numerous 1/4" or 5/16" holes in the muff endcaps in an effort to open the system up a bit. Others have completely removed the end cap and cut back the baffel up to the next internal cap. This will change the exhaust note considerably. Some think for the better, others not. You will need the rejet your carbs to accommodate any changes you make.