4 into 1 exhaust for max power?

[jimb12]

I vote for baffle with packing. When you tune the bike for it, power will be the same. I recall when our local dragstrip instituted a muffler rule. My friend's big GS (1428cc) had been running with an open megaphone up to that point. Another friend made a custom baffle for the VHR pipe and after re-tuning with it on the dyno it made the *same* power as it had uncorked.

[BigD_83]

I haven't installed mine yet, but I'm probably going to be going with baffle+packing. I live in a bit of an uptight neighborhood, and noise is a definite no no. Plus, I like to work on the bike late in the evenings, and the neighbours deserve a break.

Question for you..what are you doing with the muffler/collector connection; is it meant to be welded, or just clamped?

[DrunkenChekhov]

Did you have any issues getting the header into the ports? Mine seems like its almost a half inch too narrow spacing wise, but then again I've never installed a 4-1 so I have pretty much no idea how it should be...

[BigD_83]

Did you have any issues getting the header into the ports? Mine seems like its almost a half inch too narrow spacing wise, but then again I've never installed a 4-1 so I have pretty much no idea how it should be...

I got the engine back in the 650G this morning (30 seconds with two people moving it...slid right in) and quickly checked the BUB header against the ports. The spacing does look off just a bit. Centre to centre is correct on both the left and right set of two pipes, but it's as if the spacing between the two sets is off a bit, almost the half inch that you observed DC. I think they'll still mount with a little outward pull on the header pipes. I wouldn't think it would stress it too much.

[BigD_83]

Well, I got the header "mounted" but there were, and still remain some issues:

The spacing is definitely off on my set by 1/2" between the left and right set of two pipes. That was solved by getting the right set in the head, and then manually (no tools required) pulling gently on the other set of pipes to seat them as well. I did this with some trepidation.

The one remaining issue is that I cannot secure the #4 header flange properly (pic below). It's as if the pipe is rotated a bit, and the bolt holes on the flange won't line up square to the threads on the head. Still, it looks nice, and sits very tight to the frame and sump. At first I didn't think there was much ground clearance, but the pictures say otherwise:











there are more pictures here:

http://s1196.photobucket.com/albums/aa402/BigD_83GS650/The%20Beginnings%20of%20AliG/BUB%20exhaust%20installation/

[boontonmike]

I had the same problem with the headers. I thought I would have to redrill the #4 flange but with some fiddling was able to get the bolts both started without drilling. Just make sure you retorque the head bolts a couple times after heat cycling as my bolts loosened up quite a bit from the header seating on the gaskets.