Do reeds Fail?

Street Ryderz

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Oct 14, 2016
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3,195
But what about the fact that there was an existing expansion chamber? Are you sure there’s not a limit to fuel input given some variable (say stock pipe)


I could use some help with equation as I had been cited for no brake light at 11:29 or as I would like to say, Passing torches at high noon. How is it that I feel so inclined to rewrite rules of Principia when Einstein had already written his treatise or what have you on motion.

The calculus is all wrong! (0+11.29). This limit does not satisfy, anything!


Sorry, back to bikes
Expansion chambers over fill the cylinder when on the pipe but matching the port areas to the pumping efficiency and then the carb and pipe yeilds all that can be had!
 


FNTPuck

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Jul 2, 2018
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Street Ryderz is correct.

Reed will help your low end, but since it is usually paired with a larger carb and more fuel can often help peak HP as well. My simple piston port motor with no reed and basic mods does 53mph with no high dollar parts and is still super reliable. I still have room for further port work, reed, bigger carb, etc but I'm gonna just leave it as-is and maybe throw a triple tree on it eventually. Honestly 53mph is more than enough for a bike frame, even with disc brakes it is sketchy at that speeds due to bicycle forks and cheap thin tires. Compression is on the high side to help the low end without a reed, but still runs on pump gas, doesn't overheat, and with the sleeved jug and malossi circlips it will last thousands of miles.

Don't need a ton of money on high dollar parts for a solid build, just attention to detail and research.

As per the OP, yes - reeds can and do fail. They eventually split and start to flutter.
 

INTP_ty

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Sep 25, 2017
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53???

My Zeda, 29 mph. I should be doing ~35. The cylinder failed at one point. I swapped that (& the piston too) but I can’t remember if I cracked the case. Maybe I didn’t set a bearing correctly (friction). I do remember The cherry popping on my first MB kit after some many miles. It did like like 25-30, then one day it got louder, opened up & I had an extra 3-5mph & i could go back and repeat that every time.


Do they make an intake So I can fool around with one of those bigger carbs?
 

FNTPuck

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Jul 2, 2018
Messages
671
53???

My Zeda, 29 mph. I should be doing ~35. The cylinder failed at one point. I swapped that (& the piston too) but I can’t remember if I cracked the case. Maybe I didn’t set a bearing correctly (friction). I do remember The cherry popping on my first MB kit after some many miles. It did like like 25-30, then one day it got louder, opened up & I had an extra 3-5mph & i could go back and repeat that every time.


Do they make an intake So I can fool around with one of those bigger carbs?
They do but I don't have any links. I just made my own in 2 seconds from the flange of an old stock muffler - they happen to be almost exactly 19mm which is the size of the keihin clone as well and will bolt right up to the intake unless you have the old 32mm ones. Think I had to dremel some of the weld from the inside to make the circle flange fit the rectangle intake port but it was quick and easy.
 

inspectorcritic

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Dec 13, 2015
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1,208
I had a reed doesn't give any more power just tried to shove oil back to keep filter clean it's just another part for something else to go wrong like mounting bolts loosen half to take off the motor to get to the bolts. Junk it.
 

Karl Snarl

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Sep 20, 2019
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First reeds don't make more power anywhere it's been proven on the dyno, what they do help with is bottom end throttle response. Sthil or Minirelli cylinders unfortunately don't just bolt on ether they require the bolt pattern to be re done along with cutting the base or adding a spacer and various other things to do it right is not an easy task.
I've said it before and will again making 5-6 hp from these engines is quite easy and still in the area of being reliable (when done right) and last for years.

it's easy for those whom follow instructions or know what they are doing. a good portion of these builders have very little mechanical knowledge and this is their first journey into the world of engines. hence, why we are here in the forums, to help them learn how to create raw power from a hunk of pot metal.
 

Street Ryderz

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Oct 14, 2016
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3,195
it's easy for those whom follow instructions or know what they are doing. a good portion of these builders have very little mechanical knowledge and this is their first journey into the world of engines. hence, why we are here in the forums, to help them learn how to create raw power from a hunk of pot metal.
That was the point to my reply,Help educate and expose the myth's with common sense easy explanations.
 
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