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April 26, 2006 1:34 AM   Subscribe

49cc: 2 stroke or 4 stroke?

(you either understand the question or you don't). Hint: scooter
posted by angrybeaver to Travel & Transportation (17 answers total)
2 stroke
posted by zardoz at 1:42 AM on April 26, 2006

A 4-stroke, 49cc engine? I'd never imagined such a thing.

Definitely 2-stroke. Every time that I hear that unmistakable bee-in-a-cola-can buzz, it takes me right back.
posted by veedubya at 1:50 AM on April 26, 2006

Most likely 2 stroke, although there are 4 stroke pocket bikes.
posted by Huw at 2:48 AM on April 26, 2006

For a given engine displacement, a 2-stroke will put out a little under twice the power of a 4-stroke. They're less fiddly than 4-strokes (only three moving parts: piston, conrod, crankshaft) but they're smoky and smelly because they burn their lubricating oil by design. So it really depends what you're trying to achieve.

You'll have less trouble finding a 2-stroke engine in that size range than a 4-stroke.
posted by flabdablet at 3:46 AM on April 26, 2006

A 4-stroke, 49cc engine? I'd never imagined such a thing.

My lawnmower is a 4 stroke, and is around 50cc. This blower has a 25cc 4-stroke engine.
posted by Jimbob at 3:54 AM on April 26, 2006

Is this a choice for you? If so, get the four stroke it will be cleaner. Two stroke engines should be banned due to their pollution.
posted by caddis at 4:28 AM on April 26, 2006

Since the new EPA regs are making it expensive to import 2-stroke engines (ie meet the new regs) some scooter mfgs are really only importing 4- stroke scooters. If like me you want your 'moped' to go faster than the legal 30 MPH limit you will want a 2-stroke. They are very easy to de-restrict and gain some speed.

2-stroke = about twice the power of 4- stroke, more power from a dead stop, and cool blue smoke.
posted by Gungho at 4:30 AM on April 26, 2006

I have a 2-stroke 50cc scooter. I test-rode the only 4-stroke available (a Honda mumble) and it was slooooooow.

My Bug Jive* is a rocket-ship by comparison (although hardly what one would call fast). If I had my druthers, I'd spend the extra few hundred and buy at least a Peugeot scooter -- faster, and the slightly larger tyres make SO MUCH DIFFERENCE.

Trust me.

Also: don't even think about considering the possibility of maybe carrying a passenger. So. Frikkin. Slow.

*Random Taiwanese brand. Cheap. Cheerful. Did I mention cheap?
posted by coriolisdave at 4:33 AM on April 26, 2006

Oh, also -- my scooter doesn't smoke. At all. If I'm sitting stationary in traffic (HAH! lanesplitmenow) I can smell the 2-strokey goodness, but there is. No. Smoke.
posted by coriolisdave at 4:33 AM on April 26, 2006

Two strokes are a mess, pollution wise -- there's just no good way to do emission control when you have to do the intake and exhaust at the same time, and you're counting on backpressure to make it work. Almost all the tricks that four strokes use to control pollution either keep a two stroke from running well, or fail rapidly -- a catalytic converter would burn the oil in the exhaust and melt.

They are better at power/displacement, this is for certain, but part of that is the lack of pollution control. They also don't handle pressure changes well, leaning out badly, which is why they don't show up in the one place you'd think they would -- aircraft, where power-to-weight is incredibly important.

Four strokes are cleaner, and much more research has been done on them to make them cleaner and more powerful.

Corolisdave: If you can smell it, it is polluting -- if you can't see the smoke, it is just mixed well.

It may be that a 50cc four stroke won't have enough power -- sometimes, an engine is just too small. I'd much rather get a 100cc four stroke, than a 50cc two stroke. The air is foul enough. Back before we decided that pollution was bad, the difference between a 100cc four stroke and 50cc two stroke was small, mainly the extra oil burn, but with modern 4 stroke pollution control, the difference is vast.
posted by eriko at 5:45 AM on April 26, 2006

I have a 2-stroke 49cc and after 3 yrs of riding it it's starting to seem too slow and like I can't always keep up with traffic. The 4-stroke is slower so for that reason alone I'd say a 2-stroke is better. Being able get the hell out of the way on the road is a good thing.
posted by jdl at 5:54 AM on April 26, 2006

250cc 4-stroke. The extra one-time licensing hassle is worth the constant maintenance and pollution hassle.
posted by mendel at 6:08 AM on April 26, 2006

Evinrude has made major strides in cleaning up 2 stroke engine technology, to the point that their marine BRP injected two strokes are cleaner than four stroke engines. Not to mention having significantly longer average maintenance intervals, better idle performance, longer engine life, and greater power for a given displacement. Orbital Engine Corporation is bringing similar improvements [PDF file linked] to 2 stroke scooters.
posted by paulsc at 9:04 AM on April 26, 2006

Good god, 4 stroke.

2 strokes spew oil on your pants, pollute more than engines 10x the size, and you sound like a wheenie riding by.

4 strokes are quiet and environmentally friendly.

Honda makes a great little 50cc 4-stroke in the metropolitan. Plus, I hear you can remove the intake restrictor and get another 40% more power out of it. Of course that's probably illegal, and you didn't hear it from me.
posted by Popular Ethics at 9:41 AM on April 26, 2006

Either you're going to pollute a bunch or have an underpowered scooter. There is no best answer, unless you go for a larger engine.
posted by Rhomboid at 4:17 PM on April 26, 2006

As a matter of fact if you pick the two stroke engine you are going to pollute so much that you might as well drive a Hummer.
posted by caddis at 4:28 PM on April 26, 2006

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