Bridgestone Motorcycle Parts Discussion Board
Bridgestone Tech Talk => 350 Talk => Topic started by: davis on November 30, 2016, 01:16:16 PM
-
Thought a few would like to see a 350 muffler's internals. I like Bridgestone's attempt at an expansion chamber with a reverse cone and the baffle acting as the stinger. I did this to de-dent and clean out the carbon buildup. Not hard to do and easy to reweld with decent welding skills. I used this approach with several gas and oil tanks. The technique makes like-new parts (after chrome and paint) from dented and internally rusted or carboned parts that may otherwise have been scrapped.
- Bob
-
In my younger days, I considered splitting the mufflers and putting a prefabricated expansion chamber inside to create a "sleeper". I guess BS beat me to it. Thanks for the pics, Bob. I have looked into the ends of these mufflers many times trying to figure the internal configuration out. Now it's nicely documented.
...bert
-
My mufflers are in poor condition also and I had considered the same "hidden expansion chamber" idea! Much nicer that the flat plate that Yamaha use to reflect the wave in a rd400 muffler lol
Ryan
PS any chance of attaching a pic with the baffle inserted?
-
Here you go Ryan.
-
Hey Bob, got any sliced up GTO mufflers to complete the package? :o
-
No Bert, but a wrecked pair could be resurrected.
-
Bob, I consider you callin" 'pup Bert a compliment. ;D
...bertpup
-
My psychiatrist say it's just a case of multiple personalities.....but I got some good meds outta the visit! 8)
-
Maybe that's why there have been reports of me being in Texas...??
...bert
-
Your never alone with.............schizophrenia ::) --------------- a new slant on the old Malboro ciggy advert? anyone remember?
Anyway, very useful photos, Bob. Always thought there was an expansion chamber hiding in there, it's hinted at, on the cutaway drawing of the GTR pipe in the parts manual, P38. You've confirmed it. At the same time, they went to all that trouble to incorporate a tuned pipe in an innocuous looking silencer and then had to put damn great dents in it to clear the frame, thus upsetting the operation of the pipe !! :-[
http://bridgestonemotorcycleparts.com/PDF/BS350PartsManual.pdf (http://bridgestonemotorcycleparts.com/PDF/BS350PartsManual.pdf)
Was planning to split a corroded pipe in my collection, saved me a job. Now we can see what's in there, will have a go at making a mandrel to take some of the worst dents out of my pipes.
Brian.
-
That's a pretty good representation of the real thing in the parts catalog. This whole thread is very interesting; the pipes on mine have a loose baffle inside (secured with sheet metal screws from the outside for the last 30 years), plus a few small dents. When it comes time to rechrome them, I'll probably cut them open and fix all the problems first..
-
A question, Bob. Below the rear footrest hanger there is a clearance recess (I.E. damn great dent !) at the back of the silencer to clear the centrestand foot (I think). Does this intrude into the internal reverse cone.
Was the incorporation (disguising ?) of a tuned pipe in the silencer a first for BS on a road machine ? . I don't have sufficient knowledge of previous Japanese 2S models to answer this. Anyone?
Brian.
-
The only section of the muffler chamber that is not round is the indentation at the inlet end as shown in the first photo. The three bulkheads and the cone are round and spot welded to one muffler half (so separation is easy).
-
If you'd like to make the muffler run even quieter, just weld on some additional length to the baffle tube so that the exhaust gasses exit the chamber at the start of the cone vs. the aft end. I'm talking open, non-perforated pipe. It does not affect the reflected wave, the back pressure or the performance, but does reduce noise.
Scott
http://www.bridgestonemotorcycle.com/