Successful OEM exhaust debaffling

[CDNRatMan]

  coming together......

[greenbarn]

great news Rob... good to hear you're making progress.

[rob f]

That would be gratefully appreciated.
Not sure if I will need to do that right now but maybe in a few months. Will be away from home for a bit but might try it when I get back.
R

[Tfrank59]

well done!  I think you've started down the right road to increasing your horsepower, and if it's like my journey you'll find the next step is essential--rejetting the carb.  When I finally got my exhaust the way I wanted it (opposite you, I had to install baffles), my bike with the stock carb settings was so lean on the mixture I couldn't run it without the choke on most of the time.  So at the advice of Troll and others on this forum, I bought a Dynojet kit (around $50), watched around 3 Youtubes and dove in there to do the mod.  I was shocked--it actually worked!  the bike ran perfectly from then on, somehow I got the main jet and needle e-clip set spot-on first time, so she had instantaneous off-idle throttle response--hot or cold weather--and full power throughout the speed range.  That was my first time to rejet a carb and probably the best $50 I've ever spend on a engine mod in four decades working on bikes.  The nice thing is the whole job took only a couple of hours, most of that spent getting the tank off and everything out of the way to remove the carb itself.  If you decide you want to do it on yours, let me know and I'll send the Youtube links that made it easy enough even for me to do.

[rob f]

 After scouring this Forum and finding a few ideas  and seeing pics on opening up the stock exhaust I thought I'd give it a try.
Here is what I come up with:
The muffler stays pretty much intact, can be done on the bike in about 20 min and gives about a 30-50% increase in sound and maybe a slight performance enhancement. The power enhancement may be psychological as now I can actually hear the bike running over wind noises. I can hear when to shift and can better judge engine loads.

Procedure: (Sorry didn't take and pics because camera not available)
Remove fishtail. Using a 1" hole saw , cut a hole in the baffle plate just below the short tailpipe. This will expose the  outlet of the inner muffler . Once you see how this  exhaust system looks inside you will laugh and give your head a shake. Basically they have the 2 header pipes coming into a  baffled heavy duty tractor muffler which dumps exhaust not directly into the short tail pipe but rather just underneath it so exhaust has to travel up and out. By cutting the 1" hole under the tailpipe you have just given it a more direct route out.

Drill out rivets and take out plate in the fishtail so this newly routed exhaust can get out.

Next: if you shine a light down the output of the tractor muffler you will see another baffle plate about 16" down. You will need a 20" long shank drill bit to drill holes into this baffle. We just happen to have a selection of homemade extended bits and the best I could find was a 7/16".
There was room to drill out about 4 - 7/16" holes but opted out at only 2 which gives me a total of  almost an inch worth of exhaust rerouting. For me it proved to be enough. Can always drill out the rest later if I need to.

Caution: Not sure what this will do to fuel mix or uneven backpressure. The bike seems to run fine with no deceleration popping. Also with the new holes in the first stage baffle, I am not sure how long until heat and moisture starts to work away and start opening up the holes more. The first stage baffle mod is not reversible. The second stage baffle could be welded back up if need be.

Not a huge change, but enough without destroying that beautiful fishtail.
R