750SF3 Exhaust/Headers

[Skeeta]

GDay,
Just putting an Exhaust and headers together, from my box of pieces of a 750SF3, the headers would be after market 38mm O/D dia with 44mm collar on the head end, I then have two different exhausts(silencers) one looks an after market perhaps Staintune megaphone type which fits(38mm) then the other exhaust(silencer) is an original type cone end, 40mm opening, bit large for the 38mm headers. My dilemma is I like the original silencer(too big) Is there much difference in performance using the 38mm headers opposed to changing to the 40mm headers and using my original 40mm silencers, the headers are long enough not to use the under engine cross over pipe( although I do have one) Picture attached
Your thoughts?
Skeeta

 

[Paul Marx]

Normally, there's an intermediate under engine junction box  It's intended for 40mm silencers.
Original exhaust tube is 40mm od.

The question is, what sort of performance are you after?

Paul

 

[piranha-bro2]

Are you sure the headers are long enough and of the correct upturn to allow proper fitment and angle of the mufflers? From what i can see the non-Staintune one doesn't look like an SF2/# Conti muffler. An orig will have Conti stamped on it, with numbers and probably Pescara. The reverse cone looks too long to be SF2/3 to me.

I can highly recommend getting it right. If the headers ARE long enough, make sure they don't hang too low at the lowest point. I rebuilt an SF1 with std (I think) headers and Staintunes but the mufflers hung way too low, with crappy junction pieces and the bike looked like a hyena dragging its arse - really ugly. The owner wasn't a fast rider but said it scraped really badly when cornering - and I could see why!

I had the headers bent up a little more from the point under the from of the motor and a piece made up my the local muffler guy to get a nice upsweep for the mufflers, also expanding the pipe where nec to get a good fit between headers and mufflers. Worked really well, no welds and didn't cost much at all.

I do think you need matching size mufflers. If it were mine I'd be happy enough with the 38mm headers, but would use 40mm mufflers and have a filler section made up if nec with an upsweep.

 

[Skeeta]

Righto thanks

 

[gpacs]

There's an adaptor kit available to match a larger muffler pipe size to smaller header pipes.
https://damclassicracing.com.au/37120999-exhaust-muffler-sleeve-kit/
Although it's not the perfect solution to a high performance exhaust it is useful in this situation.