CR250R......of doom. Testing positive for Beastmode

[Formerly knownas Premixed]

I'm rebuilding my 2003 CR250R.  As most Honda people know, the 02-07 RC Valve motor is a bit on the weak side.  Sure it can be "fixed" with loads of epoxy, different carburetors, ect. But, in the end, you end up with a "good enough" motor that still is not what the previous generation was.


So...... I'm swapping the motor and carburetor all together to the '99.


You can see my 03 motor was immaculate.  I ran a PWK Airstryker off a KTM250SX and a DEP pipe and that was pretty good.  Peaky, but good. 


Surprising how close the mounts are.





My plan is to replicate this 2004 RC250M.  Throttlejockey is supplying the graphics and number plates.  I am using black wheels, and a '12 model front fender.

The bike has newer CRF Showa front and rear suspension which is being revalved by Bumpsticks tomorrow with some speed sensitive mid valving.

[_X_]

cool, what honda actually intendid with the 02.

[Formerly knownas Premixed]

I don't think so.  They just intended for their RC Valve motor to not suck, which requires a little longer intake tract, more compression, a little less crankcase volume, and a Keihin carb.  They'd have gotten around to it, but they built foopers instead.  This 99 motor was long in the tooth by 01.  It went from 92 (Jeff Stanton era) to 2001 with only small changes.

I think im going to put a Scalvini on this thing too, with a Bud silencer. 

[_X_]

sure it was, with the handling and the suspension flaws of past cr's fixed with this generation frame and excellent suspension package, geez they already had market cornered with the motor...or so they thought. now you add the motor.

[Stusmoke]

Awesome idea and I'll be watching closely. What made you choose the 99 motor over the 2000 or 2001 motor?

[Formerly knownas Premixed]

Awesome idea and I'll be watching closely. What made you choose the 99 motor over the 2000 or 2001 motor?

The 99 has the best porting in the jug.  Apparently, the 00-01 guy look for the 99 jug.

Ok so I pulled that motor apart, and not surprisingly, it's seized. 

I said if i had to split the cases AND nikasil it, im going to 295ccs, so we shall see what the cylinder plating looks like (probably shit).  Horrifying.

This motor was like a sand box inside.  Someone probably ran the bike with no filter. There was grit all in it, both rings were stuck.  Time to go all out and build a real 450-assraper.

[Stusmoke]

Awesome idea and I'll be watching closely. What made you choose the 99 motor over the 2000 or 2001 motor?

The 99 has the best porting in the jug.  Apparently, the 00-01 guy look for the 99 jug.

Ok so I pulled that motor apart, and not surprisingly, it's seized. 

I said if i had to split the cases AND nikasil it, im going to 295ccs, so we shall see what the cylinder plating looks like (probably shit).  Horrifying.

This motor was like a sand box inside.  Someone probably ran the bike with no filter. There was grit all in it, both rings were stuck.  Time to go all out and build a real 450-assraper.

Sounds good to me. The last bit anyway. So long as the 450 hasn't been run for a couple of hours... ouch.

Are you doing the rebuild yourself?

[GlennC]

Do you have to mod the frame, or mounts?
I have an 01 engine and I'm looking for a gen 3 cr 250 but I was under the impresion that the 01 engine would bolt in.

[Formerly knownas Premixed]

You have to buy or fabricate a headstay mount, and you have to ovalize the front mount tab holes about an 1/8th inch.

Yea, of course I'm rebuilding the thing myself.

[Super Trucker]

I don't think so.  They just intended for their RC Valve motor to not suck, which requires a little longer intake tract, more compression, a little less crankcase volume, and a Keihin carb.  They'd have gotten around to it, but they built foopers instead.  This 99 motor was long in the tooth by 01.  It went from 92 (Jeff Stanton era) to 2001 with only small changes.

I think im going to put a Scalvini on this thing too, with a Bud silencer.

    Sounds  like a great  project, I rode  a  pals  99 cr250   it  had   a  amazing  motor,  lineer  feel  but  strong,  it   had  low end  into  a strong  mid   then  it never  stopped  pulling.  I  left  it  wide open  to see  when  it signed off,  I was   shocked  it   just   kept  pulling  on the topend.

[Formerly knownas Premixed]

Yea, 02-07 motors do not do that.  There is so much more knowledge and support out there for the pre-02 motors. 

I might do a 270 out of this, as long as I can avoid Gorr.  Maybe rpm or pr2.

[Formerly knownas Premixed]

Preliminary research find me looking at a company called Eddie Sanders racing.  They use 92-01 CR250 motors for micro sprint cars.  They have a long rod stroker crank that they sell for not much more than a hot rods oem replacement crank.

rpm manufacturing does a 270 kit, with piston for not much more than a standard strip and re-plate job. 

I haven't done the math yet, but with the 3-4 options Eddie Sanders offers on rod length, something like a 300cc should be easy.   

My destroyed crank is a hot rods, so i am going to call them and find out about getting it rebuilt.  Supposedly those guys are "real", and by real i mean, not a warehouse in China, but rather a machine shop in the USA.

I just want to cheat as hard as possible for the 250 class.  Something like a 60hp 300cc two stroke against a 37hp 250 fourstroke.  I have to mention I am kidding, I forget sometimes that people take this seriously. But no, seriously, some 250F kid is going to take a shit in his pants.

[_X_]

if your not cheating you are not trying to win.

[TMKIWI]

If you were formerly known as premixed, What do we call you now.

Nice build btw.

[citabjockey]

"Oil Injector Man!"

If you were formerly known as premixed, What do we call you now.

Nice build btw.