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Post by nelly on Jun 21, 2020 10:57:42 GMT 1
Ok obviously a 2stroke wants separate expansions for peak performance, but can you link two cylinders to one expansion chamber? Obviously some older bikes had linked exhausts but are you just going to lose a few bhp? What you lose in power you'd gain in packaging 3 or 4 exhausts into a limited space.Better to have 2 big expansions than 3 or 4 smaller ones,any opinions chaps?
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Post by midlifecrisisrd on Jun 21, 2020 11:08:09 GMT 1
You can get more power than standard but nowhere near a good set of separate pipes
Slinger did a 2 into 1 for a 350 ypvs but he wasn't happy with it so wouldn't make me one 🙁
Steve
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Post by tsa on Jun 21, 2020 11:10:52 GMT 1
A few years ago I designed a 2-1 for the RD350YPVS and an guy who used to tune RD's called Glyn(slinger) on most forums built it in Canada. It made good midrange and lost 10% ish off the top. It sounded bloody awesome though and just needed more development which I neve had chance to do with him. I think the results were put up on some forums.
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Post by cb250g5 on Jun 21, 2020 11:15:37 GMT 1
Piper made them for the triples, and they sounded glorious. My Scott has a 2:1 exhaust. Not an expansion chamber though, many years before they were invented.
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Post by midlifecrisisrd on Jun 21, 2020 11:18:00 GMT 1
A few years ago I designed a 2-1 for the RD350YPVS and an guy who used to tune RD's called Glyn(slinger) on most forums built it in Canada. It made good midrange and lost 10% ish off the top. It sounded bloody awesome though and just needed more development which I neve had chance to do with him. I think the results were put up on some forums. I thought you were involved in it Kenny but time hasn't been kind on my grey matter When you say lost 10% was that over standard or one of your other pipe designs Steve |
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Post by nelly on Jun 21, 2020 11:19:47 GMT 1
You can get more power than standard but nowhere near a good set of separate pipes Slinger did a 2 into 1 for a 350 ypvs but he wasn't happy with it so wouldn't make me one 🙁 Steve That's what I was thinking but people doing 550s and 700s seem to run out of space and end up with ground clearance issues.Its all a compromise I suppose, food for thought 👍🏻👍🏻👍🏻 |
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Post by nelly on Jun 21, 2020 11:27:36 GMT 1
A few years ago I designed a 2-1 for the RD350YPVS and an guy who used to tune RD's called Glyn(slinger) on most forums built it in Canada. It made good midrange and lost 10% ish off the top. It sounded bloody awesome though and just needed more development which I neve had chance to do with him. I think the results were put up on some forums. Nice to know,so could be good for midrange.Is the fat part of the exhaust determined by the capacity of the cylinder or would making it fat as possible be better? I know that designing a exhaust is pretty complicated.Space, performance is all a compromise. |
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Post by tsa on Jun 21, 2020 15:22:14 GMT 1
A few years ago I designed a 2-1 for the RD350YPVS and an guy who used to tune RD's called Glyn(slinger) on most forums built it in Canada. It made good midrange and lost 10% ish off the top. It sounded bloody awesome though and just needed more development which I neve had chance to do with him. I think the results were put up on some forums. I thought you were involved in it Kenny but time hasn't been kind on my grey matter When you say lost 10% was that over standard or one of your other pipe designs Steve Steve read it again slowly lol It it was great in the midrange like 35bhp and 34lbf @6000rpm it peaked @8000rpm and reved to 9000rpm It had approx 6bhp less at prak power to a set of good 2-2 pipes. So in all it was pretty good but needed more rpm and a few things altered. A few years ago I designed a 2-1 for the RD350YPVS and an guy who used to tune RD's called Glyn(slinger) on most forums built it in Canada. It made good midrange and lost 10% ish off the top. It sounded bloody awesome though and just needed more development which I neve had chance to do with him. I think the results were put up on some forums. Nice to know,so could be good for midrange.Is the fat part of the exhaust determined by the capacity of the cylinder or would making it fat as possible be better? I know that designing a exhaust is pretty complicated.Space, performance is all a compromise. To get the 2-1 to work properly not like the ones Piper did takes some working out. Fatter would be better in this case but limits clearance and fit. Like anything in 2 stroke design its a balancing act that full of compromises. |
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Post by rigga on Jun 21, 2020 15:27:45 GMT 1
There's a guy on one of the Facebook LC pages that has a 2 into 1 pipe, does sound really nice.
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Post by dusty350 on Jun 21, 2020 15:37:25 GMT 1
+ 1 on that Rigga. It's Japanese made I think, possibly Ktec ? Dusty  |
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Post by dusty350 on Jun 21, 2020 15:43:46 GMT 1
It's on Google Videos - Ktec 2 into 1 exhaust rd350lc  Dusty |
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Post by midlifecrisisrd on Jun 21, 2020 15:52:46 GMT 1
I thought you were involved in it Kenny but time hasn't been kind on my grey matter When you say lost 10% was that over standard or one of your other pipe designs Steve Steve read it again slowly lol It it was great in the midrange like 35bhp and 34lbf @6000rpm it peaked @8000rpm and reved to 9000rpm It had approx 6bhp less at prak power to a set of good 2-2 pipes. So in all it was pretty good but needed more rpm and a few things altered. Nice to know,so could be good for midrange.Is the fat part of the exhaust determined by the capacity of the cylinder or would making it fat as possible be better? I know that designing a exhaust is pretty complicated.Space, performance is all a compromise. To get the 2-1 to work properly not like the ones Piper did takes some working out. Fatter would be better in this case but limits clearance and fit. Like anything in 2 stroke design its a balancing act that full of compromises. 😁 Can you go oval on the belly to get more volume but keep ground clearance Steve |
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Post by rigga on Jun 21, 2020 18:58:06 GMT 1
It's on Google Videos - Ktec 2 into 1 exhaust rd350lc Dusty That's the fella ..... sounds different, but in a nice way, just looks odd no exhaust on the other side. |
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Post by tsa on Jun 21, 2020 21:15:46 GMT 1
Steve read it again slowly lol It it was great in the midrange like 35bhp and 34lbf @6000rpm it peaked @8000rpm and reved to 9000rpm It had approx 6bhp less at prak power to a set of good 2-2 pipes. So in all it was pretty good but needed more rpm and a few things altered. To get the 2-1 to work properly not like the ones Piper did takes some working out. Fatter would be better in this case but limits clearance and fit. Like anything in 2 stroke design its a balancing act that full of compromises. 😁 Can you go oval on the belly to get more volume but keep ground clearance Steve You can yes but it would maybe need the same volume as the correct size circular one. |
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Post by Deleted on Jun 23, 2020 12:07:53 GMT 1
Lots of 2:1 in Japan
K2 tec is just one brand
No idea how they go though
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Post by hoist1 on Jun 23, 2020 13:06:05 GMT 1
I know Piper did 3 into 1 for Suzuki’s and someone I knew had one on his Kaw 400. Think they must have done others, had seen a GT185 with a 2 into 1 which am sure was Piper.
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Post by midlifecrisisrd on Jun 23, 2020 17:57:52 GMT 1
Yes piper did them for the GT's and kh's Some still getting them made Steve    |
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Post by nelly on Jun 26, 2020 12:55:46 GMT 1
Yes piper did them for the GT's and kh's Some still getting them made Steve Any info on that speedy with a kettle lump? Is that your handywork? That would be interesting to look at? |
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Post by midlifecrisisrd on Jun 26, 2020 13:10:01 GMT 1
Yes piper did them for the GT's and kh's Some still getting them made Steve Any info on that speedy with a kettle lump? Is that your handywork? That would be interesting to look at? Its a guys over on the 2 stroke forum It's in the large strokers section under Triumph steam triple I think Steve |
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Post by nelly on Jun 26, 2020 13:17:05 GMT 1
Nice I'll go and have a look 👍🏻👍🏻😎
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Post by lolly on Jun 26, 2020 14:59:17 GMT 1
back in the 80s a friend of mine had a piper 3-1 on his gt380 ; sounded like a screaming banshee ; i will never forget that sound
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