Stinger Length?

U

User 27079

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Yeah, he drills it to the 8mm holes.
Hey mate, what xpansion chamber do ya run and what is the diameter and length of the stinger on yours?
Mine is now 5/8" wide and a bit over 3.5" long, compared to the 1/2" wide, 2 1/4" long stinger tube that originally came attatched to the SBP chamber.

I keep thinking that i should have made it a bit longer?
 
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U

User 27079

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I have run the cdh66 and then the mz65. I would have to measure the cdh but the mz is 7/8 od - 5/8 id but that has a bigger chamber than the sbp pipe.

I honestly don't know enough to help but @gary55 posted a link to Jennings book https://motoredbikes.com/threads/tinkering-with-stock-exhaust.53968/page-5#post-478852
Thanks :)

Yeah mine is now the same, 7/8od and 5/8id
I mean everything seems to be good and running great.
I read that but didn't really understand so i tried with some numbers and came up with a little more than i had to work with so i just bit the bullet and
went for it.

Seems to be spot on, concerning the hill pulling power and the speed, so far.
Still haven't gotten to 500 miles on this cyl yet though.

Thanks mate :)
 

Spare_Parts

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Nov 29, 2017
Messages
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That's kinda what I do. Just mess with stuff until I'm happy with the results. Do plan on reading more of Jennings book before I start porting or cutting the new pipe though.
 
U

User 27079

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That's kinda what I do. Just mess with stuff until I'm happy with the results. Do plan on reading more of Jennings book before I start porting or cutting the new pipe though.
Was skimming through it and seen where he says the outlet pipe (stinger?) isn't so much affected by the length (if not to long), as it is the
diameter ( the 5/8id?) and something about 12 times the size of the id.

So, if i am correct, i am like 3 inches short of the calculated length, but there is a happy medium
between calculated length and being to short.
I think i am there.

However, having rode the bike this way for a day, everything seems to be where i need it, so far,
hill pulling power/oomph and the get up to speed quickness is more than i had.

Why doesn't SBP make them like this, instead of the small outlet pipe :unsure:
Perhaps i am just wrecking my engine? :eek:
 
U

User 27079

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Also read where he placed the outlet pipe a bit into the last cone so it gets the reverberation effect?
So when i tacked my outlet pipe i placed it 3/4 of an inch into the last cone like jennings said.

Crazy this stuff is. Alot to learn and have learned from you all here! (y)
 
U

User 27079

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Second modified SBP expansion chamber with a longer outlet tube at 7" long and 5/8" id.


IMG_20190211_152706.jpg
 
U

User 27079

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Tacked with the welder and brazed sealed then ground down and sanded smooth.

Let me know what ya'll think, as i am just curious to know :p
 
U

User 27079

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That is a 1" briggs muffler on there and if need to add a bit more restriction to flow,
i am thinking to add the smaller 3/4" briggs to the end of the bigger one

Thoughts anyone?
 
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