Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

December is here and I'm anxiously waiting for some good snow to arrive.  I've been bit by the 2 cycle bug recently.  I have the Toro 421QE, which is the 4 cycle version of the 221Q.  I thought it may be redundant to pick up a used 221Q so I've been looking into getting a Toro Powerlite.  Plus, I can hang the Powerlite up on a wall.  the 221Q is too big and heavy to do so.

Anyways, anybody got a recommendation for a compact SS two-cycle?  If not, please provide a 7 step sure fire way to cure the 2 cycle habit.  :)

borat wrote:
That's interesting, I've never heard/considered that perspective, about the piston coming up and changing direction without resistance during the exhaust stroke. I'd offer a mild "counter-argument" that it changes direction just as quickly at it bottoms out during each stroke, also not fighting any pressure. And that aspect remains the same for a 4-stoke or a 2-stroke. One difference I suppose is that the connecting rod is under compression when it changes direction at the bottom of the stroke, whereas it is in tension when doing it at the top of the stroke, for whatever difference that might make (not a whole lot, I'd think). I'd expect that a bigger contributor to the fact that 2-strokes tend to rev higher is that there is no reciprocating valve train to deal with. No valves to float, valve spring tensions to deal with, and less reciprocating mass.

On the note of comparing 2-strokes to 4-strokes at the same displacement, I don't think that's quite a fair comparison. As the 2-stroke fires twice as often, they typically have a higher power/displacement ratio (maybe a 200cc 2-stroke is 6 hp, vs 4 hp for a 200cc 4-stroke, to make up numbers). Comparing engines of the same horsepower or torque would seem more fair. But I have little doubt that you can also rev up the 2-stroke substantially higher than the 4-stroke, when messing with the governor.

Don't take any of this the wrong way. I think 2-strokes are interesting, and just got one that I'll hopefully get to try out this winter. Just having a discussion.

Certainly valve train limits a four stroke engine ability to rev.  Even differences between valve configurations, (flat head, OHV, OHC and DOHC) will have an effect on how well an engine will handle high rpms. 

Without valve trains to consider,  the only things in common with four and two stroke engines is crankshafts, connecting rods, wrist pins, pistons and rings.  Therefore the application of those items need to be understood.  That's why I focused on those components in my explanation.  Two cycle engines can be revved without load to very high rpms and not be subject to the potential damage that is more likely to occur in a four cycle engine.  Spinning a four stroke to extreme rpms without a load can possibly cause connecting rod big ends to go a bit out of round.  At least that used to be the theory.  Two strokes on the other hand have their pistons always on either a power stroke or a compression stroke thus keeping everything under a constant load. 

You ever wonder why two cycle engine cranks are pressed together while four cycle cranks are usually machined from one piece?    

         My Harley 1200 cc (4 cycle)  has a pressed together crankshaft

royster wrote:
Do you know why?

I agree with jrtrebor - the Cr20 is one of the best old 2 stroke toros.  The video posted there is mine.

The powerlite is OK but I like the CR20 much better :-)

borat wrote:

A Harley engine is quite unique , in that the crankshaft consists of basically 2 flywheels with one main bearing sandwiched betweem them., onto which both connecting rods are attached , The  distance  of the main bearing  from the center of the flywheel  determines the length of the stroke, Therefore the crank is made in 3 pieces and pressed together ..  The Harley V-Rod   has the same arrangement but the crank is a one piece forged unit.

royster wrote:
Does it have a single piece roller bearing for the big ends?  Can the connecting rods be removed without taking the crank apart?

superbuick wrote:
Not disagreeing with you guys, but trying to see how the CR20 is better.  Both Powerlite and CR20 has the same size engine, curved auger.  The CR20 is 20" wide, versus 16" for the Powerlite.  Seems like the Powerlite should throw snow further with the chute, and the CR is much better only with slush due to the vane discharge.  Is that it?

Someone is listing a CR20 on CL for $250.  Seems a bit high for a 20+ year old snowblower.

royster wrote:
I don't know how this thread started with 2 cycle snowblower and got into a 4-cycle motorcycle.  

aa335 wrote:
Something to do with pressed cranks. 

Maybe Harley should look at converting their twins to two cycle engines.   If they get it right, they might begin to make something with some horsepower.  I can only imagine the tone of a 1400+ cc, lumpy two cycle.  Hey!  HD guys buy the bikes for their sound, they might just like the new flavour!