2-stroke powered ninja 250r?

[81cr450]

I'm sure I'm not the only one on here who's had the thought of a 2-stroke powered ninja 250r.
What I'm wondering is anybody "seen" any links anywhere of completed build's. Fabbing a whole bike would be beyond me, but a conversion I could manage.
I'm thinking it couldnt be much different than building an AF bike. Ideally I like the new CBR 250 r honda with a kx500 motor in it, cause the steel frame would be easier to work with & it's gotta be slimmer with a single cylinder motor which would make everything line up better kicker & sprocket wise.
If I was to use the 2008+ ninja250 I think the banshee motor would be a better pick to fit the twin cylinder frame. I've seen one of the 1st gen 250 ninja's done on youtube but it wasnt very informative & was only a buzz up & down the street
cr500 builds would even interest me , just trying find more info period.
As far as a single cylinder & vibes , it really wouldnt be any worse than in a dirtbike would it?
Thanks for any input

[Tosh Togo]

An RZ350 engine would be worth a look. It's about the same size as your EX250 engine is, but makes more power and weighs less. A Banshee engine would work just as well... you'll be making custom pipes anyway.

[jar944]

Originally Posted by 81cr450

I'm sure I'm not the only one on here who's had the thought of a 2-stroke powered ninja 250r.
What I'm wondering is anybody "seen" any links anywhere of completed build's. Fabbing a whole bike would be beyond me, but a conversion I could manage.
I'm thinking it couldnt be much different than building an AF bike. Ideally I like the new CBR 250 r honda with a kx500 motor in it, cause the steel frame would be easier to work with & it's gotta be slimmer with a single cylinder motor which would make everything line up better kicker & sprocket wise.
If I was to use the 2008+ ninja250 I think the banshee motor would be a better pick to fit the twin cylinder frame. I've seen one of the 1st gen 250 ninja's done on youtube but it wasnt very informative & was only a buzz up & down the street
cr500 builds would even interest me , just trying find more info period.
As far as a single cylinder & vibes , it really wouldnt be any worse than in a dirtbike would it?
Thanks for any input

The 500cc 2t singles vibrate.. a lot. The counter shaft dictates engine placement and dirt bikes are considerably narrower then most street bikes. because of that Getting a functioning kick start seems almost impossible due to the frame width.

I've thought about a banshee/RZ powered 250 ninja, I even have a banshee motor sitting in my garage waiting to be swapped into something.

Originally Posted by Tosh Togo

An RZ350 engine would be worth a look. It's about the same size as your EX250 engine is, but makes more power and weighs less. A Banshee engine would work just as well... you'll be making custom pipes anyway.

Pipe fitment on the twin is the issue. keeping it inside the faring would require some effort.

[81cr450]

Looks like a bit of room for "a" pipe, might could make room for 2 if you put cutouts in fairing kinda like they do to car hoods when a turbo is peeking through.

My question about a big single could have been better phrased maybe. I've been riding 2t 500's for the last 10+ years the vibes dont bother me , would it be worse or amplified in a street bike. I realize you'd need to gear it so it would be in the smooth spots at cruise RPM but...

An RZ350 motor would be good but I think you could get a better powervalve set up with something like the T-rex jugs as well as go bigger. No doubt a twin would be the smoothest, the banshee motors where barely bolted into the frame compared to a dirtbike single

Offset sprockets arent a big deal to shift the motor over to help with a kicker throwing the weight off center much would be a big negative though

[Motorrad]

Originally Posted by 81cr450

I'm sure I'm not the only one on here who's had the thought of a 2-stroke powered ninja 250r.
What I'm wondering is anybody "seen" any links anywhere of completed build's. Fabbing a whole bike would be beyond me, but a conversion I could manage.
I'm thinking it couldnt be much different than building an AF bike. Ideally I like the new CBR 250 r honda with a kx500 motor in it, cause the steel frame would be easier to work with & it's gotta be slimmer with a single cylinder motor which would make everything line up better kicker & sprocket wise.
If I was to use the 2008+ ninja250 I think the banshee motor would be a better pick to fit the twin cylinder frame. I've seen one of the 1st gen 250 ninja's done on youtube but it wasnt very informative & was only a buzz up & down the street
cr500 builds would even interest me , just trying find more info period.
As far as a single cylinder & vibes , it really wouldnt be any worse than in a dirtbike would it?
Thanks for any input

Kawasaki sucks... why would you want one of those.... get a honda...


haha..



Okay..

I always thought one of those with a HOT HOT built 250R atc motor would be fun..

[81cr450]

The reverse kick would actually work quite well & its counter balanced , 6 speed , 90 hp with a Liger jug

[Motorrad]

Originally Posted by 81cr450

The reverse kick would actually work quite well & its counter balanced , 6 speed , 90 hp with a Liger jug

exactly what I was thinking....

[jar944]

Originally Posted by 81cr450

Looks like a bit of room for "a" pipe, might could make room for 2 if you put cutouts in fairing kinda like they do to car hoods when a turbo is peeking through.

My question about a big single could have been better phrased maybe. I've been riding 2t 500's for the last 10+ years the vibes dont bother me , would it be worse or amplified in a street bike. I realize you'd need to gear it so it would be in the smooth spots at cruise RPM but...

An RZ350 motor would be good but I think you could get a better powervalve set up with something like the T-rex jugs as well as go bigger. No doubt a twin would be the smoothest, the banshee motors where barely bolted into the frame compared to a dirtbike single

Offset sprockets arent a big deal to shift the motor over to help with a kicker throwing the weight off center much would be a big negative though

The vibrations may or may not be more, it would depend on the mounting and frame rigidity. I wouldn't think it would be much of a change either way. It's the constant speed vibration that would get annoying.

For the banshee, a serval / or cheetah powervalve setup (420 to 485cc) would be plenty of motor. Then swap in a RZ transmission and you have enough gearing for the highway.

Offset sprockets put more load into the counter shaft bearings, I would avoid them.

[Navin]

I'm trying to build a decent bike out of a 2013 Ninja 300. The engine is the best part of the bike. There are better chassies to swap a 2t into. Search CL for parted out GSXRs. A roller from any 600 SS would be a far better base to start with.

[2trally]

Have you seen the 450 mono gp bikes? I think it would be easier to start with something like a kx500, change the suspension, gearing, subframe and wheels. Then fabricate some fiberglass bodywork for it. You would end up with a lot lighter bike and there wouldn't be as much custom fabrication.

Okay, maybe there would be more custom fabrication, but I think your less likely to run into a problem that will stop the project cold by changing the suspension and subframe than by changing the engine.

[Andyinhilo]

You might try to find one of these :

[Motorrad]

just go find a RD500 and get it over with.. spend money... and ride..

[High Country Herb]

Is alignment that big of a deal? I would mount the motor with the sprocket lined up, then make a custom kick starter to fit the area. A simple dog leg bent into a stock kicker should do the trick, right?

They used to have some cool 125 and 250 2-strokes at Laguna Seca during the MotoGP races.

[jar944]

Originally Posted by High Country Herb

Is alignment that big of a deal? I would mount the motor with the sprocket lined up, then make a custom kick starter to fit the area. A simple dog leg bent into a stock kicker should do the trick, right?

They used to have some cool 125 and 250 2-strokes at Laguna Seca during the MotoGP races.

On a 125/250 yes, that will work. On a 500 the extra outboard leverage WILL break the case.

[81cr450]

Gixxer weight is the hangup 424 lbs w/fuel . compared to near a 100 lbs less with the 250 size bikes

The offset sprocket does work you just need an additional bearing set up to the outside. Definitley more fab work though. & I have thought that you could poly mount in a cage with no movement available so it just dampens the vibes

A cheap more modern suspension bike is why I'm not looking at the buy & ride type. I have a real hard time just riding "stock" machines, tinkeritis bad, Thats half the fun putting it together & making it work.

I do have the KX550, SUMO really would be the easiest & probably the lightest.

The 250r motor shifted to the sproket side all the way would leave you more room for a pipe on the other side & you could bend the kicker on it as long as you had a decompressor in the head.

Thanks for the idea's & the cool pics of the sweet old iron Guy's
. I admit it's a bit of a PIPE dream at the moment, but thinking it through has really brought in some great ideas. More input definitley welcome.

Horse power wouldnt be as big of structural detriment as weight, I've read on some other forums that it would just trash a bike doubling the horsepower that the factory intended, but you see guys do that & more on Banshee's & other machines with no ill effect & considering you'd be losing weight with a lighter motor wouldnt that be a big positive structurally?