250cc Please?

[Johnj]

I just spent 10 minutes wondering why a 2 stroke should be so much more powerful than an equivalent-displacement 4 stroke engine.

I couldn't figure it out. Nothing seemed that different. I was thinking about valving, exhaust, fuel mixtures, etc. I was going nuts. I was about to post here asking, and then I wrote the "4" in 4 stroke and realized what the answer was.

That's my story for the evening. Goodnight

Hmm, i still don't know what a stroke is can someone please, in easy terms tell me what is the difference between cc and strokes?

The reason is that a 2-stroke engine has a detonation every rotation of the camshaft. 4-stroke engines have detonations every *other* rotation of the camshaft. Hence a 2-stroke engine of similar displacement will produce more power.

I'm pretty sure that johnythan means crankshaft not camshaft.
A 2-stroke engine fires every time the piston crosses top dead center.
A 4-stroke engine fires every other time.

[Sev]

For simplicity:

A stroke is the movement of the piston in one direction.

Down, is a stroke
Up, is a stroke


A two stroke engine produces a "power stroke" every time the piston reaches top dead center.

A four stroke engine has an extra 2 strokes:
Suck, Squeeze, Bang, Blow

Suck - the piston goes down while the intake valve opens air/fuel is drawn into the cylinder
Squeeze - piston goes up, compressing the air/fuel mixture
Bang - the spark plug fires forcing the piston back down
Blow - the piston goes up and the exhaust valve opens the exhaust gasses are force out of the cylinder.

So, two stroke because of its design detonates every time the piston goes up. A four stroke goes up and down and up and down (take forever!) to make power.

[slimcolo]

I understand a 2 and 4 stroke. But has any one ever heard of a "Miller" 5 stroke? I don't know how they work , but they were experimented with in the 20s. I read an article that one of the auto makers, I believe Hyundai, is testing an updated "Miller" motor.

I don't under5stamd how an engine can have an odd numbered stroke! Unless it double fires.

[Johnj]

Do you mean this Miller 5-stroke.

[Nibblet99]

All this talk about strokes, and you'll leave the wankel engine feeling all left out. didn't some old Norton's use this one?

http://en.wikipedia.org/wiki/Wankel_engine

[jonnythan]

I'm pretty sure that johnythan means crankshaft not camshaft.
A 2-stroke engine fires every time the piston crosses top dead center.
A 4-stroke engine fires every other time.

Doh. Of course. Thanks.

[slimcolo]

Thanks JohnJ that is what I needed. I also found out the Miller was from the 40s not the 20s. And the car company is Mazda not Hyundi.

Nibblet99 that is the best representation of a Wankle I've seen. Not only Norton but also Hercules and Suzuki also used the Wankle.

[slimcolo]

aaaaaaa xxxxxxxxxxxxxx

[flynrider]

All this talk about strokes, and you'll leave the wankel engine feeling all left out. didn't some old Norton's use this one?

I don't remember a Norton Wankel, but I did take a ride on a Suzuki RE-5 Wankel powered bike. Suzuki sold it for a few years in the mid 70s. Nice idea, but the world wasn't ready for a Wankel powered bike. On the upside, it was probably the smoothest motorcycle engine I've experienced. On the downside, the gas mileage was just miserable. My friend averaged about 30 mpg on his 500 cc RE-5. The exhaust note was quite unique for a motorcycle.

[slimcolo]

Don't believe the Nortons ever made it to NA. Primarily used for Police in UK.