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Post by stinger440 on Oct 26, 2012 16:21:33 GMT -5
So in the last month I have saw two pics of whips with twin pipes. Actually just saw one was a massey. They look Aaen and are installed in a crossover configuration. Both sets have looked identical. Does anyone know who could have made these? Could they be from an early kaw? Trying to decide if the dual pipe setup is something worth pursuing or not.
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Post by scorp11 on Oct 26, 2012 21:51:46 GMT -5
So in the last month I have saw two pics of whips with twin pipes. Actually just saw one was a massey. They look Aaen and are installed in a crossover configuration. Both sets have looked identical. Does anyone know who could have made these? Could they be from an early kaw? Trying to decide if the dual pipe setup is something worth pursuing or not. I don't have an answer for you, but I'd like to make a dual carb / dual pipe setup myself. Someone recommended trying 2 Polaris Indy 650 pipes. The bore and stroke is the same which apparently means something for pipes. All the ones I've seen so far are Aaen pipes. |
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Post by mooreperformance on Oct 27, 2012 12:23:56 GMT -5
The biggest improvement that can be made to any two-stroke engine is to eliminate the "Y" pipe in the exhaust system of a twin cylinder engine. There is absolutely no way that a two-stroke/twin cylinder engine can have a scavenge style exhaust system with a single exhaust pipe and "Y" pipe. The exhaust pulse must travel back up the pipe to keep the fresh-charge from exiting the cylinder before the exhaust port closes.
A "Y" pipe (connecting the two cylinders together) completely confuses the returning exhaust pulse rendering it useless.
A (so called) aftermarket high-performance single pipe can increase horsepower a small amount by being less restrictive but doesn't keep the exhaust port from over-scavenging the fresh air/fuel mixture with a returning exhaust pulse. A single pipe with a "Y" pipe can only increase horsepower by acting as a megaphone (it has no return pulse characteristics).
The theory of a tuned expansion chamber on a two-stroke engine is barely understood and is extremely complicated. The finest two-stroke engineers in the world have a hard time grasping the concept and designing a good system. Throwing a "Y" pipe into the design process and understanding how it affects scavenging/reverse pulse tuning on a twin cylinder engine makes it impossible!
With the extremely limited amount of space for exhaust pipes on a two-stroke street motorcycle, has anyone ever seen a "Y" pipe on a two-stroke motorcycle? Even the three-cylinder Kawasaki and Suzuki two stroke street motorcycles had a pipe for each cylinder.
Unfortunately the snowmobile industry has taken the EASY way out and installs a "Y" pipe on all of its engines, even the high performance snowmobiles.
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Post by obj1 on Oct 28, 2012 19:55:08 GMT -5
No Y-pipe here.  |
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Post by obj1 on Oct 28, 2012 19:57:43 GMT -5
Twin pipes need twin carbs too.  |
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Post by obj1 on Oct 28, 2012 20:00:07 GMT -5
Sometimes adding a 3rd cylinder helps too for the "BIG" class  |
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Post by scorp11 on Oct 29, 2012 22:48:18 GMT -5
Sure hope you never have to turn right with that dual carb setup :-)
So, care to share what those pipes started out life as ? Or are they one of your own creations ?
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Post by obj1 on Oct 30, 2012 22:54:17 GMT -5
What? thats not how your going to run your dual card setup? The pipe on the right is one we made for a 340ss in a stinger chassis. sounds great, wont beat a stocker!! the other pipes we made for the cuyuna/whip and did well with it this year in mod stock classes. A handfull of firsts. Actually we ran these pipes on a stock 440 also when we had trouble with the "mod" engine and they actually made it rip! We won 2 mod stock classes at willow river with a stock engine(dont tell anyone) so they work ok for us.
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Post by scorp11 on Oct 31, 2012 0:49:14 GMT -5
Not quite what I had planned for dual carb :-). So what would it take for me to get a set of pipes like that built for me  My custom whip would be real cool with dual pipes and dual carbs !! |
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Post by admin on Nov 1, 2012 23:44:45 GMT -5
No Y-pipe here. I can't believe how good that looks. |
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Post by admin on Nov 1, 2012 23:46:46 GMT -5
The biggest improvement that can be made to any two-stroke engine is to eliminate the "Y" pipe in the exhaust system of a twin cylinder engine. There is absolutely no way that a two-stroke/twin cylinder engine can have a scavenge style exhaust system with a single exhaust pipe and "Y" pipe. The exhaust pulse must travel back up the pipe to keep the fresh-charge from exiting the cylinder before the exhaust port closes. A "Y" pipe (connecting the two cylinders together) completely confuses the returning exhaust pulse rendering it useless. A (so called) aftermarket high-performance single pipe can increase horsepower a small amount by being less restrictive but doesn't keep the exhaust port from over-scavenging the fresh air/fuel mixture with a returning exhaust pulse. A single pipe with a "Y" pipe can only increase horsepower by acting as a megaphone (it has no return pulse characteristics). The theory of a tuned expansion chamber on a two-stroke engine is barely understood and is extremely complicated. The finest two-stroke engineers in the world have a hard time grasping the concept and designing a good system. Throwing a "Y" pipe into the design process and understanding how it affects scavenging/reverse pulse tuning on a twin cylinder engine makes it impossible! With the extremely limited amount of space for exhaust pipes on a two-stroke street motorcycle, has anyone ever seen a "Y" pipe on a two-stroke motorcycle? Even the three-cylinder Kawasaki and Suzuki two stroke street motorcycles had a pipe for each cylinder. Unfortunately the snowmobile industry has taken the EASY way out and installs a "Y" pipe on all of its engines, even the high performance snowmobiles. MP, As I've mentioned before, you could fill a book with your knowledge of this stuff. Always appreciate your info! |
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