butre
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from what I hear RX8s still need a full rebuild at about 90,000 miles, give or take depending on how much hooning was done. still better than the thousand or so miles between new rings a 2 stroke often needs
v-twin 2 stroke?
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HeadSmess
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pretty well much. but the plain steel seals are a lot cheaper than the older hardened things they used in previous engines. and no chatter marks being left in (epi?)trochoid means no expensive housing to rebuild/replace. those apex seals really suffer, and dont have a self sealing effect like standard piston rings have. up to a spring and centrifugal force to do the job.
then theres the whole combustion area shape that has really bad efficiency, hence the twin plugs normally seen in rotors, and the five throttle cables used by suzuki when they made their rotary bike... they had to figure out a way to give compression braking. by seriously advancing the ignition when the throttles released. not an issue on a car but a bike is a bit different...
they use oil. another bad thing.
spark plugs have to sit in an awkward place which again, reduces efficiency.
popular in light aircraft. small and powerful, simple to tear down for the mandatory service schedule, smooth running, and the seals etc last virtually forever when they only do one speed all day long.
but still, i would love to have a small one regardless! bwap bwap bwap bwap...
felix originally designed them as compressors...a job they do really well. also very good as steam/compressed air motors as they can be double acting.
then theres the whole combustion area shape that has really bad efficiency, hence the twin plugs normally seen in rotors, and the five throttle cables used by suzuki when they made their rotary bike... they had to figure out a way to give compression braking. by seriously advancing the ignition when the throttles released. not an issue on a car but a bike is a bit different...
they use oil. another bad thing.
spark plugs have to sit in an awkward place which again, reduces efficiency.
popular in light aircraft. small and powerful, simple to tear down for the mandatory service schedule, smooth running, and the seals etc last virtually forever when they only do one speed all day long.
but still, i would love to have a small one regardless! bwap bwap bwap bwap...
felix originally designed them as compressors...a job they do really well. also very good as steam/compressed air motors as they can be double acting.
AutOtaku
Member
Taking apex seals into account, a small rotary wouldnt be as hard to rebuild as a larger one (such as 12A/13B) but it would still be expensive. On the subject of burning oil, the OP was talking about a 2 stroke V twin, That would burn just as much oil i would assume
HeadSmess
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nah, in that regard... the rotary is usually run at 100:1 or less. not terribly bad.
they still dont meet emissions control crap, so thats why you dont see many other sizes in common use. theyre just novelty engines.
the OS 5cc one doesnt have any side seals, just the three apex seals. they apparently last a fairly long time, but not as long as the ringed fourstrokes (that sound better in planes anyway)
problem with a multi cylinder 2-stroke is having to separate the crankcases. unless the pistons are at tdc at the same time, which would then be a nightmare to balance...
they still dont meet emissions control crap, so thats why you dont see many other sizes in common use. theyre just novelty engines.
the OS 5cc one doesnt have any side seals, just the three apex seals. they apparently last a fairly long time, but not as long as the ringed fourstrokes (that sound better in planes anyway)
problem with a multi cylinder 2-stroke is having to separate the crankcases. unless the pistons are at tdc at the same time, which would then be a nightmare to balance...
Rico glover
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No need for a twin 2 or 4 stroke. 2 stroke are very unreliable once you start playing with all of its characteristics(Ports,pistons,ignition,carburetor,exhaust etc) it overheats or melts with high HP(7-9) on all model 66s ( Chinagirls, HT, skyhawk American made you name it piece of s*** in my opinion But I did build a reliable 5 1/2 horsepower 4-stroke motorbike that's capable of 60 mph so I'm happy. Powerplant came off a 90cc Baja dirt bike and has yet to fail me
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AutOtaku
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Getting back to the original post, If you really wanted a twin cylinder, an inline would be the most likely i would think....
F
Fennec
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There is a mini chopper pocket bike I saw once that had an incomplete V-twin. It was a Chinese made model and it took quit a bit of work to make a manifold and Y-pipe exhaust for the engine, but I now have it on a West Coast Choppers bicycle with 20" mag aluminum Mongoose wheels. Highway speeds are nothing since I had a friend make custom tires for it and balanced the wheels.
HeadSmess
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thats not actually inline, is it? its a tandem triple. like the kawasaki KR250 used. with an extra cylinder.
not trying to fault you work, thats amazing, but the point remains...its three separate engines, not one combined engine with preferably all cylinders driving on one common crankshaft.
hmmmm. you could probably cast up a nice case to take two HT cylinders to drive a common clutch shaft, but ideally you have the cranks contrarotating so the crankweights cancel out (wack some spur gears in there!). the whole reason kawasaki took the tandem approach. it revs a lot higher with less vibration, and as most high RPM singles and twins still resort to a balance shaft in an attempt to cancel out the crankweight vibration, its a better use for the extra bearings and shaft. use them to MAKE power, not absorb it!
even most cars with their apparently "balanced" four cylinder engines run balance shafts...
not trying to fault you work, thats amazing, but the point remains...its three separate engines, not one combined engine with preferably all cylinders driving on one common crankshaft.
hmmmm. you could probably cast up a nice case to take two HT cylinders to drive a common clutch shaft, but ideally you have the cranks contrarotating so the crankweights cancel out (wack some spur gears in there!). the whole reason kawasaki took the tandem approach. it revs a lot higher with less vibration, and as most high RPM singles and twins still resort to a balance shaft in an attempt to cancel out the crankweight vibration, its a better use for the extra bearings and shaft. use them to MAKE power, not absorb it!
even most cars with their apparently "balanced" four cylinder engines run balance shafts...
JerboaJohn
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kinda cool, but something isn't right about them.
the RC guys have twin 4 strokes under $500, most are inline 20-40cc but they get their 2-4hp @25000 rpm, so clutching and gearing would be a problem.
the RC guys have twin 4 strokes under $500, most are inline 20-40cc but they get their 2-4hp @25000 rpm, so clutching and gearing would be a problem.
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