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So what do we think of this little number. ??


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So, what are the advantages of a 2 stroke twin over a similar displacement single?

More weight per cc.

More friction (2 little ends, 2 big ends, more piston circumference) per cc.

Presumably a simultaneous firing boxer, so still fires every 360°.

Potentailly better primary balance.

I suspect much of the appeal is in just having a 2 cylinder engine.

Multi cylinder engines in this size can produce more power than singles IF they are run very fast.

If you want a screaming banshee with the associated peaky power and substantial reduction gear, then this is for you.

That said, I have to admit that a 7 cylinder 4 stroke radial paramotor engine would have my attention.

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All things even, the single has more torque than a multi. Torque is what accelerates you. Add the less weight of a single vs a multi, the single is far quicker off the line than the multi (bike as an example)

The multi has smaller pistons, less internal part weight, etc., and thus the multi can spin faster and thus can produce far more horsepower. Horsepower is what pushes you thru the air and the multi has far better top speed.

In paramotoring I’m not sure…. Might be lighter, might spin up faster but with the lacking torque I’m not sure if that would be the case.

Things that make you go hemmmmmm

Could it be marketing at work here?

Put me down for a 7cyl too! It will make my glider go faster hehehehehehehehe.

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PT, do you think it's a true boxer? Doesn't look long enough in the crank for the extra journal.. If not it could vibrate more than a single.

Interesting question.... never thought of that! If it has one journal per piston it will really be smooth.

But really does not most of the vibration come from the prop?

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A 2 stroke boxer cannot use a single throw crank.

Induction is by displacement into the crankcase, if one piston was moving into the crankcase while the other was moving out, there would be no net displacement and therefore no induction.

It doesn't need much extra length to fit the 2 throw crank in, the offeset between the cylinders need only be about twice the thickness of the coneecting rod.

The power you can get from a high revving multi cylinder engine tends to be quite peaky. You won't get much power at all until you get into the high revs, then it will come on quite rapidly.

Many of us will remember the RD250s and 350s of the Seventies; gutless up to 6000rpm and rocketship performance from 6000rpm until the inevitable bang.

One of the nice features of the Bailey 4 stroke engine is the smooth, progressive power.

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RD250s and 350s

Remember the RD500 V4?

yamaha-rd-500-02.jpg

Man I ton of people are 6 feet under due to this unit (Race unit any teen with money could buy)

I remember the RD well... Anyone that was riding in 1st-2nd-3rd gear and past the 6k only needed to let off and quickly twist the throttle back to full. This would result in the rider on their back in traffic or worst on their back in the meat wagon.

Crazy bike.

Yea your right single throw is only in 4 strokes right.

So from what I read its a 160cc engine. So not matter what the engine should/will have more then enough bottom end for a paramoter (crazy topend).

also it seems to be targeted for the race applications (makes sense). I'm also guessing it will cost around 6k+ just for the motor

With this engine the race guys will be able to fly a 14m-16m wing lol

Sexy it is!

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RD250s and 350s

Remember the RD500 V4?

yamaha-rd-500-02.jpg

Man I ton of people are 6 feet under due to this unit (Race unit any teen with money could buy)

I remember the RD well... Anyone that was riding in 1st-2nd-3rd gear and past the 6k only needed to let off and quickly twist the throttle back to full. This would result in the rider on their back in traffic or worst on their back in the meat wagon.

Crazy bike.

Yea your right single throw is only in 4 strokes right.

So from what I read its a 160cc engine. So not matter what the engine should/will have more then enough bottom end for a paramoter (crazy topend).

also it seems to be targeted for the race applications (makes sense). I'm also guessing it will cost around 6k+ just for the motor

With this engine the race guys will be able to fly a 14m-16m wing lol

Sexy it is!

Paul Bailey has said the new hornet paramotor will be around the same price as a V5.

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YPVS and EXUP are different animals.

EXUP simply opens a valve to reduce the restriction of the exhaust system of a four stroke engine at high RPM, above that at which noise testing is carried out. :twisted:

YPVS is variable valve timing applied to a 2 stroke engine. I believe the principle was established in the 1920s on split singles with movable cylinder liners. 8)

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???

I had a YPVS, its a slide that opens and closes at the outlet ports.

The exup valve is similar but further into the exhaust.

Just been for an awesome blat on it as it happens :-) :-)

SW :D

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The YPVS valve was, as I remember it, a rotating drum with a cutaway which formed the upper edge of the exhaust port in the cylinder. Rotating the drum altered the point at which the exhaust opened and closed, permitting the engine to make more effective use of the tuned pipe scavenging over a wider range of RPM.

Edit: There was a sliding version of the YPVS valve in the TZR engines.

Getting back to the original post, if Paul Bailey can supply this for the same price as a V5 motor, he will have a long queue of 2 stroke enthusiasts (i.e. perverts :lol: ) at his door.

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