Dropping cc's

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Jason Pitcher

Born to tinker, forced to work.
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Now I know it is possible to gain cc's by doing certain things but is it possible to go down. Like going from 94 cc to 80. Would it be as simple as putting on a smaller p/c or would it be more complex?
 
Smaller bore or a crank with a shorter stroke. Each has its own problems. Most people don't want to do that work for less performance. Sometimes car or motorcycle engines get downsized but usually its to fit into racing displacement classes.
That makes sense. It is just something that has been rolling around in my brain.
 
With some saws this is doable.
IE a 372 can become a 365, a 272 to a 61, a 92cc 066 to a 85cc 064.

Smaller cc saws can rev higher with everything else being equal, that's about the only advantage to down sizing.
If you had a 372 and cut nothing but small wood a ported higher revving 365 cylinder would be faster but on the flip side you can also put a bigger rim sprocket on the 72cc saw for more chain speed so not many downsize.
 
With some saws this is doable.
IE a 372 can become a 365, a 272 to a 61, a 92cc 066 to a 85cc 064.

Smaller cc saws can rev higher with everything else being equal, that's about the only advantage to down sizing.
If you had a 372 and cut nothing but small wood a ported higher revving 365 cylinder would be faster but on the flip side you can also put a bigger rim sprocket on the 72cc saw for more chain speed so not many downsize.
I didn't figure it was common practice. Most want more power than less.
 
Personally I see no reason to go down in displacement. For example a 266 could be made into a 61cc or 72cc saw. Weight of the saw is the same regardless of engine size. If you wanna do it just to do it that’s fine, or if your looking to save on fuel. Why not just buy a smaller cc saw?
 
Personally I see no reason to go down in displacement. For example a 266 could be made into a 61cc or 72cc saw. Weight of the saw is the same regardless of engine size. If you wanna do it just to do it that’s fine, or if your looking to save on fuel. Why not just buy a smaller cc saw?
Just something I was curious about.
 
Now I know it is possible to gain cc's by doing certain things but is it possible to go down. Like going from 94 cc to 80. Would it be as simple as putting on a smaller p/c or would it be more complex?
I HAVE HEARD A TRICK ON old outboards to reduce HP for small lakes (e.g. HOA restrictions) was to put gasket w/ smaller opening between carb and intake manifold.= RESTRICTS MAX
 
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