My sons KX60 (little 2 stroke dirt bike) makes 15 hp, stock. My 60 cc saws make about 1/3 of that. Ive taken both apart, the major differences I see are reed valve on the intake and a tuned expansion pipe on the exhaust.
...and pipes.
What is the difference in stroke on these two?My sons KX60 (little 2 stroke dirt bike) makes 15 hp, stock. My 60 cc saws make about 1/3 of that. Ive taken both apart, the major differences I see are reed valve on the intake and a tuned expansion pipe on the exhaust.
What is the difference in stroke on these two?
Why does a .357 Magnum produce so much more power than a .38spl ? They're the same size bulletMy sons KX60 (little 2 stroke dirt bike) makes 15 hp, stock. My 60 cc saws make about 1/3 of that. Ive taken both apart, the major differences I see are reed valve on the intake and a tuned expansion pipe on the exhaust.
What is the difference in stroke on these two?
Its the pipe mostly.
The aprilia factory engineers tested their RAS125 without the pipe and with re-optimized jetting. results 54hp with the pipe, 18 hp w/o
The short stroke and short rod also hurt power output, then the air cooling brings down the max power as well.
The "pipe" helps but without the port timing the gains from the pipe aren't as high as you'd like to believe. The only way that you get the port timing is having room which requires a longer stroke. Longer stroke makes faster piston speed. The speed in which this all happens makes reed valves super effective. Trapped volume allows for a more complete charge transfer. So many variables and things that I don't really care about typing as they don't really need to be on a saw forum. But this gives you an idea.
Flywheel effectCase volume, stroke, cylinder size and the ability to 4,5,6 transfers, water cooling, weight takes a on a relatively lesser import...
I'm confused on the" longer stroke makes faster piston speed" I thought the opposite?The "pipe" helps but without the port timing the gains from the pipe aren't as high as you'd like to believe. The only way that you get the port timing is having room which requires a longer stroke. Longer stroke makes faster piston speed. The speed in which this all happens makes reed valves super effective. Trapped volume allows for a more complete charge transfer. So many variables and things that I don't really care about typing as they don't really need to be on a saw forum. But this gives you an idea.
Flywheel effect
I'm confused on the" longer stroke makes faster piston speed" I thought the opposite?
Well which engine would rev more short stroke.If the piston has to travel a farther distance and the crank is turning the same speed the piston will be moving fast as it has a longer distance to travel.
Of course port timing on a non piped piston port engine is vastly different than a reed valve piped engine, however the outcome remains the same. A 2t engine without a tuned pipe will never come close in power output to one with a pipe.
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