Ok I have this bike a Suzuki fz50 it's like from the 80's. Well as we all know you should never ride a moped offroad but who can resist. Well long story short my pipe broke off. I was wondering would a Rm125 pipe do the dual purpose of silencer and expansion chamber. The stock pipe was a straight pipe with a silencer. This is a 2 stroke too i'm all confused. It'll be funny though because i'm gonna race it at the Walnut pit bike race if they have it.
FrankenBike.
- Thread starter Roost165
- Start date
jaguar
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It had a straight pipe (like 4 strokes have) all the way to the silencer?
Any pipe with an expansion chamber would help it out then I'd think. But using a 125s pipe on a 50 might make the 50 only have top end power.
Better would be to use the old pipe and have a welder create on it a small expansion chamber (maybe half the diameter of the 125's).
Any pipe with an expansion chamber would help it out then I'd think. But using a 125s pipe on a 50 might make the 50 only have top end power.
Better would be to use the old pipe and have a welder create on it a small expansion chamber (maybe half the diameter of the 125's).
frankenbike
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- Jun 29, 2000
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Hey what's the big idea taking my login name?
(just kidding)
The name comes from my first bike which was pieces of several other bikes, but mostly a 76 XL175.
(just kidding)
The name comes from my first bike which was pieces of several other bikes, but mostly a 76 XL175.
MONKEYMOUSE
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- May 10, 2001
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Why not use a YSR50 pipe its 2 stroke with a small chamber. I bet it would fit and you can pick them up cheep on Ebay.
A fatter pipe makes more lowend, if i remember what i read about cone shapes on 2-stroke pipes. But you lose topend with more backpressure. I had wondered about putting a 125 pipe on a 250 or vice-versa to see How it would affect it. Rejetting would be fun im sure. Think about a 250 that was as peaky as a 125... I think i will let my friend test-ride it!!
Anyway, i wouldnt assume it will gain power from a real pipe, it might not have enough topend to sacrifice with a nice fat expansion chamber.
A YSR 50 is a highly tuned engine, not quite the same league as the fz50 i imagine.
Just my random ramblings. Take it or leave it
- Later
Anyway, i wouldnt assume it will gain power from a real pipe, it might not have enough topend to sacrifice with a nice fat expansion chamber.
A YSR 50 is a highly tuned engine, not quite the same league as the fz50 i imagine.
Just my random ramblings. Take it or leave it
- Later
Wait...what engine damage will occur running a two-stroke without an expansion chamber? My only guess is it might mess with the airflow and in turn the jetting and then a lack of oil. Fill me in. More backpressure = more lowend and less backpressure = more topend?
jmics19067
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- Jan 22, 2002
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think of a garden hose <straight pipe> this setup tends to favor extremely smooth easy to use low end power. Beginner bikes, chainsaws and weedwhackers although no pipes are closer to straight pipe characteristics than expansion chambers.
think of a garden hose that was trying to pass a football through it,bulge in the middle with slightly tapered cones. This shape has more of a "hit" to the power delivery but wide and controllable.older non powervalved bikes and big dirt bikes ,cr500 etc.
think of a garden hose trying to pass a basket ball, large bulge with steep cones . this is a high revving hard hitting top end of power,think screaming 80's in the expert class.
To build an expansion chamber correctly you will need to measure just about everything in your engine,go thru a long and tedious math problem to know what kind of cones and where they go to help the dimensions of the engine. And then hope the engine can dissipate all the extra heat it is trying to harness so you don't melt the piston. To guess on making your own pipe your chances are better that you are going to have less power than you already have in most of your rpm range if not all the range or melt the piston than you have getting lucky .
think of a garden hose that was trying to pass a football through it,bulge in the middle with slightly tapered cones. This shape has more of a "hit" to the power delivery but wide and controllable.older non powervalved bikes and big dirt bikes ,cr500 etc.
think of a garden hose trying to pass a basket ball, large bulge with steep cones . this is a high revving hard hitting top end of power,think screaming 80's in the expert class.
To build an expansion chamber correctly you will need to measure just about everything in your engine,go thru a long and tedious math problem to know what kind of cones and where they go to help the dimensions of the engine. And then hope the engine can dissipate all the extra heat it is trying to harness so you don't melt the piston. To guess on making your own pipe your chances are better that you are going to have less power than you already have in most of your rpm range if not all the range or melt the piston than you have getting lucky .
you didnt answer my question, a fatter pipe has more bottom, obviously think of the FMF Fatty and a narrower pipe has more top, think of the FMF Rev pipe....but what engine damage will occur running a two-stroke engine without a expansion chamber or any pipe to create back-pressure?
jmics19067
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- Jan 22, 2002
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I dont think there would be any damage from not running a pipe alone. if there was any damage it would be from incorrect jetting or foriegn objects finding there way into the port and hitting the piston. wheedwhackers,chainsaws and such have no pipe.
Although the pipe diameter and length has a lot to do with it the angle of the cones and where/how they are placed is what makes the pipe an expansion chamber.
Although the pipe diameter and length has a lot to do with it the angle of the cones and where/how they are placed is what makes the pipe an expansion chamber.
