Inline Twin Two Stroke

[Atc GuY]

Hey all, has anyone attempted to build an inline 2 cylinder 2 stroke engine? Something using existing cylinders off a machine like a 80CC or 125CC dirtbike and maybe a bottom end from a snowmobile? I was thinking about the possibilities of mating 2 80CC cylinders to a 125 or 250 bottom end and using that to power a motorcycle. Just a thought, somewhere around 40 HP would be great to power the new Ninja 250 frame. Thanks in advance.

[jadleybray]

there actually are some manufactured for crotch rocket racing, two stroke Nr250? NSR? cant remember. Honda built, not street legal, two 125 cylinders. There was a dude back east that had one in a drag frame for a bit but never had good results. Not sure what that means but there was never any talk about it. I do know that that motor Honda claims put out 80HP stock!!!!

[Atc GuY]

Ya, those are exactly what I was meaning. The NSR250 or even some of the Aprilla's. I think it would be awesome to remake an engine like that and put it into a cheap, yet current frame. Getting the cylinder porting right seems like it would be very difficult though.

[Vealmonkey]

So are you meaning inline with the frame or inline at 90 degrees to the frame? Inline with the frame would take some engineering if you are talking a true inline. If you are talking a v-twin type engine, then that may not be so bad. I'm thinking with a true inline engine that runs with the frame, then you would have the transmission hanging along outside the center point of the frame and then you would have to have some kind of wormgear setup, to realign your power transfer to the rear sprocket of the bike.

[jadleybray]

123670

Here ya go, this is the NSR250 motor, basically a twin 125

[Vealmonkey]

That's not what I would call inline, and that is what was leading to my confusion. If you consider that inline, then it makes many engines that would qualify.

[jadleybray]

These are considered a 90 deg V Twin, so no its not an "inline" motor. I just knew what ATC Guy was referring too even though he used the wrong terminology.

[jeddy]

Inline twin two stroke would be a banshee style. If you really wanted an interesting two stroke V style, look into the RD/RZ500. Or if you don't like Yamahas the Suzuki RGV500 is interesting. Problem is they are both V4's and probably hard to find in the US. It's gonna be hard to stuff four pipes under the rear fenders. I can only assume Honda and Kawasaki had engines similar to these also. You could always look for an old rotary Suzuki RE5 if you really want something different (although it's just a single rotor, and I still don't know if they should be considered a 1, 2, 3, or 4 stroke...)

[mi500]

Check these guys out. out of Austrailia and make some fun looking rides.

http://www.twostrokeshop.com/two_stroke_shop_engines.htm

[Atc GuY]

I was referring to inline as how a snowmobile engine is set up. I'm sorry if I used the wrong terminology. I was invisioning a Banshee style, to jugs next each other rotating the same direction as the rear wheel (no 90* gearbox/worm gear needed.) The 90* twin looks like a really cool idea, I'll have to check into those and see how the lower end is put together.

[fabiodriven]

The Yamaha RD motor is an air cooled in line two stroke. It was the platform for the Banshee motor and it came in a few different sizes. I know for a fact there were 250's, 350's, and 400's, and I'm pretty sure there was even a 125, all twins.

As stated already, I wouldn't refer to a motor of this configuration as "in line" either.

[Bretmd94]

Pretty impressive sport bike they sell. An Aprillia 250 with a custom 500cc twin 2-stroke motor!. Now only if it didn't cost $22,000....


Check these guys out. out of Austrailia and make some fun looking rides.

http://www.twostrokeshop.com/two_stroke_shop_engines.htm

[Atc GuY]

I'm meaning twin instead of inline. My bad, sorry for the confusion. I wonder if a person could get their hands on a NSR250 or another 250 GP racer engine? It would be a bike that turned a lot of heads.

[Vealmonkey]

If you are only thinking twins, you are thinking small. I have a trike frame that has RD350 engine mounts already in it. It would take RD400 or RZ350 or banshee engine if you made radiator mounts. Kawasaki made 500 2 stroke triple and 750 2 stroke triple, which I have a 72 h2 750 and they also made a 750 triple 2 stroke snowmobile engine that was a single speed centrifugal clutch, so there is way more and larger engines to choose from.

[RapidRick]

Every once and a while you can still find a RD350 3 wheeler for sale in Southern California. There was one in San Diego about 6 mo. ago.

[ironchop]

dont forget about the suzook GT series........ the RamAir 380,550, and the 750 water buffalo (liquid) triples....they made another displacement smaller than the 380 but I cant recall what the displacement was....I had good luck with the air cooled GT`s but I don`t think they have the kinda power my Kaw triples had

[willreed03]

For aircooled the RD250 motor will take the RD350 jugs, pistons, and heads for instant bolt on power which makes a very fast bike. The RD400 is slightly larger and does not use a whole lot of the same parts as it's little brothers. I had a 73(?) Suzuki T350 inline twin 2 stroke a few years ago and that thing was fast. It would power the front end off the ground in the first 3 gears.

However if you are looking for a more modern engine go with a Banshee motor, tons of aftermarket options plus the 6 speed tranny. Just have to figure out where to put the rads. Or if you want to stick with air cooled build a Blaster motor, they have big bore kits that go up around 240CC I think plus the 6 speed tranny. I know it's not a twin but it would be a cool bike nonetheless.