W
WorkingOnWise
Guest
In planing my project, I reallllllly don't want to go past the 49cc limit, but I also really need at least 3hp, and closer to 4 to be realistic, to do what I want. My bike plans are discussed in the thread "Heavy Hauler Project".
I did some quick math and found that a 49cc engine is 3 cubic inches. I have build several high performance engines, and it has never been a problem to get a reliable 1hp per c. i. d. out of an automotive engine, and still be very ''streetable" 1.25hp per cid was in reach if I was willing to give streetability and gas milage, and 1.5hp per cid was doable if I as also willing to give up durability as well. That translates into a 350hp Chevy 350, a 430hp, and 525. A 350hp 350 is a very fun engine, good power, good gas mileage (for a V8) and very streetable.
Now, to bring those numbers to a bicycle engine, I know we are talking a 2 stroke and not a 4 stroke, but a 2 stroke will typically get you higher hp numbers that a comparable size 4 stroke.
So, what do I not know that explains why we don't see 49cc 4hp 2 strokes? That's what I need for my project. Is it just a matter higher compression and a stronger connecting rod? I assume the crank in a typical 2 stroke in not a weak link, and in my experience, cranks fail from vibrations and lack of lube, rods fail from rpm's and compression pressure.
If I build a super strong rod, say from titanium, and bumped the compression to 11 to 1, would I have a 49cc 4hp engine I could rely on? What would break then?
Thanks
Keith
I did some quick math and found that a 49cc engine is 3 cubic inches. I have build several high performance engines, and it has never been a problem to get a reliable 1hp per c. i. d. out of an automotive engine, and still be very ''streetable" 1.25hp per cid was in reach if I was willing to give streetability and gas milage, and 1.5hp per cid was doable if I as also willing to give up durability as well. That translates into a 350hp Chevy 350, a 430hp, and 525. A 350hp 350 is a very fun engine, good power, good gas mileage (for a V8) and very streetable.
Now, to bring those numbers to a bicycle engine, I know we are talking a 2 stroke and not a 4 stroke, but a 2 stroke will typically get you higher hp numbers that a comparable size 4 stroke.
So, what do I not know that explains why we don't see 49cc 4hp 2 strokes? That's what I need for my project. Is it just a matter higher compression and a stronger connecting rod? I assume the crank in a typical 2 stroke in not a weak link, and in my experience, cranks fail from vibrations and lack of lube, rods fail from rpm's and compression pressure.
If I build a super strong rod, say from titanium, and bumped the compression to 11 to 1, would I have a 49cc 4hp engine I could rely on? What would break then?
Thanks
Keith
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