Cr 250 Motor Swap

[ThePhantomRider]

I have a great roller chassis and I have a Cr 2502 stroke that I don't ride but with a fresh motor, I was wondering if I could drop the motor into the chassis?

My questions, I know the 500's have problems because they aren't counterbalanced, is the same true for the 250? Also can it be balanced to reduce the vibration or will I have to go find a 250r motor instead.

Reason being is I have a chassis I can use for all types of riding, and with this motor the quad will be at about 260-275lbs dry.... So I'm thinking a ported and polished 250 2 smoke in a 270ish pound quad would be the chit.

Let me know.

[Motofool250r]

the cr250 isnt counterbalanced it will vibrate lots possibly crack the mounts but it will work with fabrication.

[ThePhantomRider]

Can it be counterbalanced? Or is that a separate part that requires different cases. I know quads but hell, I don't bother with motors.
I'm guessing it's going to have to be a 250r motor...

If we can get one cheap, may go 330 kit on it as well...make it light and make it fast!!!

Oh and for those that may worry about chassis strength. it's been tested with a hevy 450 motor in it so we can lighten a lot of stuff up since the motor weighs less. We can lighten spindles and such...

Vanquish...

[Motofool250r]

you would need new cases to counterbalance a cr250,

you can balance the motor to minimize vibration, but it will still be pretty apparent ina quad.

you can pickup a 250r motor pretty cheap these days.

strength and ability to resist cracking from vibes are totally different stresses, it could handle big jumps all day but be subjective to cracking with too much carbon content in the metal its a trade off man strong doesn't mean the righ stress wont get to it.


id say go with whatever motor yo find in good condition for good rice, there is a cr500 a guy is doing in theis forum it looks good. but be aware of the vibe issues.

[BuB400]

I never understood the whole vibration issue. Why would you notice it more in a quad frame than a bike frame? You would think it would be the opposite.

[Motofool250r]

more metal to resonate the vibrations through, id guess

[dynofox]

Originally posted by Motofool250r
more metal to resonate the vibrations through, id guess

I had a tri z 250 (yamaha 250cc 2-stroke 3-wheeler) and that motor was not counterbalanced. The vibrations were not bad at all with that machine.

[ThePhantomRider]

No I get the damage vibration can do to a frame. I also figured the cases were different with the quad motor so that's what we discussed today, going to do at least a fully rebuilt 250r or go with an ESR 310 or 330 kit....It's going to be amazing....

Vanquish...

[factoryX]

lol I had a tri-z to, and it would shake itself apart if you did not check the bolts every once and awhile.

[dynofox]

Originally posted by factoryX
lol I had a tri-z to, and it would shake itself apart if you did not check the bolts every once and awhile.

Really? Mine wasn't that bad. :confused:

[250r grave yard]

the forks on a dirtbike or 3wheeler asorb the vibs and also has 1 tire on the ground as a 4wheeler has shocks a bit diff from forks and 2 wheels on the ground

[factoryX]

yeah the tri-z is known for loosing swing arm bolts and nuts...

[BuB400]

Originally posted by 250r grave yard
the forks on a dirtbike or 3wheeler asorb the vibs and also has 1 tire on the ground as a 4wheeler has shocks a bit diff from forks and 2 wheels on the ground

Huh?

[250r grave yard]

it has to do with a dirt bikes forks asorbing the vibs

what kind of 450 shocks are you lookin for