why the big pipes?
- Thread starter Bignig604
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Brandon H.
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- Mar 26, 2009
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Ok, I will try to explain how I understand it works. Might be wrong.
As the piston goes down in the cylinder the pressure from it shoots the new air/fuel mixture through the ports and into the cylinder while at the same time removing the nasty burn fuel out the exhaust. In the process, some of the new fuel/air goes out the exhaust with it. The pipe is shaped so the harmonics of the exhaust actualy pushes the unburnt gas/air mixture back into the cylinder.
I might be wrong, just hope I don't sound stupid. I have a pic I can post in a bit
As the piston goes down in the cylinder the pressure from it shoots the new air/fuel mixture through the ports and into the cylinder while at the same time removing the nasty burn fuel out the exhaust. In the process, some of the new fuel/air goes out the exhaust with it. The pipe is shaped so the harmonics of the exhaust actualy pushes the unburnt gas/air mixture back into the cylinder.
I might be wrong, just hope I don't sound stupid. I have a pic I can post in a bit
A 2-stroke engine running a straight pipe will run, but not well, as the shape of the pipe is an integral part of the engine's tuning. Also, if you remove back pressure from a 2-stroke engine, you risk burning the piston/ring around the exhaust port, because of it not having a sufficient charge of fresh premix.
Brandon H.
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- Mar 26, 2009
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WOOT!! :aj:IndyMX said:
I have been listening to yall. This noob (me) is learning :whoa: :cool:
Brandon H.
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- Mar 26, 2009
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This is what i was talking about
helio lucas
~SPONSOR~
- Jun 20, 2007
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to answer the question on two stroke pipes on 4st and 4st pipes on 2st:
both have been employed in the past and currently are.
the modern design expansion chamber on 2st act just like a compressor. but they do not start on this shape. the first atempts some 70 years back was just megaphones, yes megaphones. like the ones being employed on 4st flat track, moto gp, some mx designs etc, etc...
a lot of 4st pipes are designed to have a expansion chamber but some are hidden, just cylindrical boxes.
and plain straight pipes are also used on two strokes not only on 4st. trial bikes, industrial engines, boat and snowmobiles etc are some exemples...
of course, one cannot just swap it, but both have they´re pros and cons and can be made to suit the aplication.
generically writing, on both engines straight pipes are mostly seen on low performance engines while expansion and\or conpression pipes are related with high specific power (Kw per cc) high rpm, narrow power band, racing engines.
confusing? :cool:
both have been employed in the past and currently are.
the modern design expansion chamber on 2st act just like a compressor. but they do not start on this shape. the first atempts some 70 years back was just megaphones, yes megaphones. like the ones being employed on 4st flat track, moto gp, some mx designs etc, etc...
a lot of 4st pipes are designed to have a expansion chamber but some are hidden, just cylindrical boxes.
and plain straight pipes are also used on two strokes not only on 4st. trial bikes, industrial engines, boat and snowmobiles etc are some exemples...
of course, one cannot just swap it, but both have they´re pros and cons and can be made to suit the aplication.
generically writing, on both engines straight pipes are mostly seen on low performance engines while expansion and\or conpression pipes are related with high specific power (Kw per cc) high rpm, narrow power band, racing engines.
confusing? :cool:
Brandon H.
Member
- Mar 26, 2009
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word yo its like braaappp braaapp
helio lucas
~SPONSOR~
- Jun 20, 2007
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actually is not 180 degrees, or the spark will fire at bottom dead center. is just a matter of put the timing of the spark on the other side of top death center. if its 2mm before TDC, just move it to 2mm after TDC.(retard the timing twice the amount of the advance)SHSPVR said:
many gp engines have cranckshafts running backwards.
A question for some of the old timers...
didn't Ray Martino<SP?> Tony D's mechanic before he got a ride with Suzuki, take an obscure European bike that had a timing curve that was backwards set up the engine and trans to run backwards because it ran better that way?
didn't Ray Martino<SP?> Tony D's mechanic before he got a ride with Suzuki, take an obscure European bike that had a timing curve that was backwards set up the engine and trans to run backwards because it ran better that way?
Filthy_McNasty
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- May 9, 2007
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Four-strokes don't use expansion chambers because they use valves to control the air flow. Two-strokes use the positive and negative pressure waves in the pipe to perform the function of valves. The divergent and convergent cones of the pipe are what determine the frequency and amplitude of the waves.
