Topic: CB750F 4 into 1 exhaust - " header to muffler " diameter please

[IndianRider]

just borrowed my friends 1998 CBR 1100 XX Black Bird muffler and it fit the stock headers perfectly ..so perfect that it did not allow for any gasket material in between. 

aesthetically, its a bit too long and a bit too big and heavy .. clears the swing arm by an inch but had to rotate the muffler a bit .. im thinking of cutting the midpipe so the bolt hole on the muffler will line up with the rear footrest bolt so i can install a metal hanger .. the muffler may then look short enough and also big and beasty and i hope the look would grow on me atleast ..

was too late to start the bike up in the garage as im in a townhome and didnt want to wake up the neighbors  .. will update you all on the sound tomorrow ..it should sound very quiet and muffled as the blackbird is soooooo quiet with these stock dual mufflers on ..

some pics ..



 

[IndianRider]

here is a pic of the cbr 1100 xx muffler cut at the midpipe and made to adapt the 4 into 1 headers . .not the look i wanted but its ok for now and really quiet ..

ps: looks like the yamaha roadstar warrior muffler style to me  ..

[jdigga]

Whoa, that looks pretty beefy!  Can we hear what it sounds like?

[merc2dogs]

one thing comes to mind: HUGE

 what is that 7" diameter?

[IndianRider]

it doesnt sound like anything .. it is SILENT .. just like the stock dual mufflers on the CBR 1100 XX blackbird .. heavily muffled ..  the only thing you can hear is the motor noise .. 

dunno know about the diameter .. i will measure it ..

need to go to the CBR 1100 black bird forums so see if the muffler can be modified for a slightly louder noise ..  the can is sealed so the baffle is not removable, but i think i can drill holes directly into the baffle via the holes in the chromed cap of the end of the muffler as you can see in one of the pics ..

[Kev Nemo]

Bringing it back from the dead..

so 4-1 exhaust, 2.5 inch collector can I step down to a 2 inch inlet muffler?

[mrbreeze]

Like already mentioned....you could go to a muffler shop and get a reducer. If you are piecing a system together...you usually have to make adjustments ....placement of muffler,mounting locations etc.
Anything is certainly doable if you have the $ (+ skills & tools).

[Kev Nemo]

I guess I should have been more explicit. I want ONE step down, at the 2.5 inch collector, to be able to have one long continous pipe to the end end of the muffler. I plan on slipping the shorty muffler slightly into the pipe and putting a thick,grindable weld on it. Is 2.5 to 2 inch to big a drop, back pressure-wise or should I cut up on the muffler alittle more to get 2.25?

The exhaust I have has a step down about 5 inches down the pipe, then what appears to be another, THEN the muffler. It looks like crap to say the least.

I know I asked before, but my thread got hijacked and dropped...

[Kev Nemo]

Bump-need to get this finished tomorrow

Is 2.5 to 2 inch to big a drop, back pressure-wise or should I cut up on the muffler alittle more to get 2.25?