What donors would you use for this project?

Discussion in 'The Garage' started by dirtydeeds, May 5, 2012.

  1. dirtydeeds

    dirtydeeds I'm alive.

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    Anyone ever put a 250cc (or similar) into a really small chassis?

    Like what Honda did with the CRF250 junior?

    I've had friends put multi cylinder street bike engines into quads, with varying success. I know stuff like this gets done in local garages. (with beer)

    The trick would be to find a worthy chassis- disc brakes, decent sub frame, suspension and a large tank, and an engine that would be worth the trouble to do it.

    The idea would be to end up with a sub 200lb bike, capable of holding a bit of luggage, doing highway speed and have a seat height low enough that a 5' person could flat foot it.


    Ideas?
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  2. dentvet

    dentvet Long timer

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    The 200 pound parameter is tough. What is highway speed?

    125 mx bike is 200#. KDX200 into 125 chassis is common and could be lowered. 6 speed tranny might be hiway tolerable

    3/4 chassis xr200 crf230 etc already too heavy but could go 60 mph. might be enough room in the frames to get more motor

    Youth bike chassis. kx100, crf150 could probably get a bigger 2 stroke in there, probably not a 4 stroke due to the tall cylinder and head

    kdx200 or ktm200 motor in kx100 chassis has probably been attempted in the pit bike world

    gas gas pampera bike might be close to what you specify
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  3. Dave in Wi

    Dave in Wi Long timer

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    I can't help but think of the KTM Freeride. 220 lbs., 350cc, detuned but it sounds like a ton of fun.
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  4. ridewestKTM

    ridewestKTM Long timer

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    If I understand the question "small" is like stature - seat height... I agree with the two-stroke idea and there are ways to make a two-stroke more pleasant for street. NTL if 4-stroke is preferred and the head height is a problem, there were 250 and 350 Arammachi horizontal singles. Sold under a number of names such as Harley Davidson. These were really low to the ground. Seems too that some of the scooters (including current models) have the same layout
    perhaps not a help but might get you on a new train of thought.
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  5. henrymartin

    henrymartin Mr. Tourguide

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    KLR250 can be lowered and with the 6 speed tranny will comfortably cruise on the pavement. Switch the front end to something with decent brakes, and the rear shock to something that isn't a pogo stick.
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  6. vtwin

    vtwin Air cooled runnin' mon

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    Saw an article once of a Fuji Rabbit scooter with a Ninja 250 drive train. He called it Ninja Rabbit. He did have to machine his own wheels, added disc brakes etc. It was pretty cool and could well exceed legal speeds, even Montana legal speeds.:eek1
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  7. dirtydeeds

    dirtydeeds I'm alive.

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    I like the scooter engine idea. Some of them would have a different lay out and offer more options. Those arammachi singles sound interesting.

    CRF230L > 200 lbs
    KLR250 >200 lbs
    125MX chassis = too tall. (You would have to take 8" out of suspension)


    I did look at the KX100/KTM105 bikes. They would be a good chassis. They make big bore kits for the KTM, and it's a 6 spd. It would be constantly out of gas and premix can be a bummer. A 4 stroke 250 would be nice in it. Perhaps a KLX250 engine in a KX100 chassis?

    The Free Ride is almost an option. Still tall, and a bit heavy.
    The CRF250junior is claimed to be about 180lbs.
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  8. dentvet

    dentvet Long timer

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  9. henrymartin

    henrymartin Mr. Tourguide

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    Don't forget that KLR250 is a 6 speed, 4 stroke. Can go at 70mph quite comfortably, plus geared low for some off road stuff. Super Sherpa engine should be even lighter being air cooled.
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  10. Navin

    Navin Long timer

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    TTR125/DRZ125 type playbike base with a BB motor build IMO.

    http://www.powroll.com/P_YAMAHA_TTR125.htm

    170cc with a cam & carb, who-whooo!

    KLX140L, 209 lbs claimed curb and start boring and stroking till you get the power you want.

    Even a CRF150F aircooled trail bike weighs 236 ready to ride, claimed anyway.

    Getting it plated is another story. :lol3
    #10