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Anyone cut open a Gyro s Muffler ?

Posted: Tue Sep 04, 2012 9:00 am
by Tenacious T
I'm just trying to finish a 86- Gyro s - 4000. mi restore . The last thing is a pluged muffler . First Q: Are Gyro mufflers real heavy ? I've already tried tapping with a hammer - to useing an air chisel w/ blunt end against a piece of 3/8" flat stock . That neted a small nut can of carbon chunks . Sand blasted and painted w/ barb a Q black . Ran great (32 mph ) for about 10 mi. Next I tried the Chemical method w/ Liquid Plumber . Ran good for 10 mi.then pluged again . So - I was thinking about cutting the bottom out , cleaning out , then tig welding back together . Any suggestions ?

Re: Anyone cut open a Gyro s Muffler ?

Posted: Tue Sep 04, 2012 5:22 pm
by motomech
Are you sure it's clogging with carbon. I used to blew though them like playing a tuba[leaves a nice black ring on your kisser, LOL].
What I used to find, is that the really heavy mufflers were so heavy because the fiberglass packing that lines the inside of the muffler body gets saturated with oil and the reason the power goes away in 10 minutes or so, is because that's about how long for the oil to start to give off fumes, effectively hindering the exh. flow.

Carbon or oil, you have two options. Cut the muffler body in half[about 2/3 rd.s of the way back] and using an acetylene torch, burn out the oil/carbon. This is a really messy, smokey job that can take hr.s.
Or, if you can deal with a little more noise, give the muffler a "steel enema". I used to use a 14" long 5/8th" drill in a big two-handed motor and drill the muffler lenght-wise from the butt end. Much, much easier.

Re: Anyone cut open a Gyro s Muffler ?

Posted: Fri Sep 14, 2012 9:15 am
by Tenacious T
So - I went ahead and cut open the exhaust . I tried to post Pic's but were to large , untill i can figure out how to make smaller I can email them to you . I started by first cutting off the end thinking I could clean it out that way ! Don't do it - it was a dead end . Next I cut out a large section of the bottom w/ a hacksaw and a cut off wheel. Inside was a lot of carbon and a center baffle . Knocked out the remaining carbon and removed the center baffle and bead blasted the inside . Muffler is made up of a stainless screen - sound deadening material - outer shell . The last 8" of the exhaust is a 3/4" nipple that enters an open area that leads to the tail pipe that makes a U turn then out the back . With it all cleaned out I tacket it back together minus the center baffle . Took it to a Guy up the road that does Tig welding , first asked what his credentials were ? Well he worked for Williams Int. ( as in the Cruise Missile ) . The resaults were very good ! Flat ground w/ 230 # 28- 32 mph 35 down hill . When you let off the gas it has that nice 2-stroke "cluck " if you know what I mean ! T

Re: Anyone cut open a Gyro s Muffler ?

Posted: Sat Sep 15, 2012 7:26 am
by GSX1400
You could host your pics on Photobucket?
I'm curious to see what it looks like inside...

Re: Anyone cut open a Gyro s Muffler ?

Posted: Sat Sep 15, 2012 5:09 pm
by motormike
GSX1400 wrote:You could host your pics on Photobucket?
I'm curious to see what it looks like inside...

...+1...wanna see
Sounds like performance change for the good,
a little ear candy as a byproduct.... :thumbwink: