Gen 4 CRF450 to CR250 Conversion - Help Needed

[317]

Recently I've acquired a 1996 CR250 which was the last year of the steel chassis. Originally I was going to graft on an '02-newer front end, rebuild the shock and call it good. It wasn't long after that I found an '05 CRF450R roller which changed the game plan!

I'm now contemplating swapping the '96 motor in the '05 chassis which has brought me here! I've been digging for a while but I've yet to see anyone that has made the swap without butchering the right side cradle to clear the side cover and peg mount casting. I've seen a few swaps but it seems like most skip over this important part and fail to photograph this trouble spot. SO, I'm here to see if anyone has some insight on what exactly is involved in making this work.

Plan 'B' is to snag a 2004 CR250 frame and build off of that. I have access to one relatively cheap and if the above option is too involved I might go this route. From what I've read this would be as close to bolt-in as it gets.

Thoughts, comments, ideas?! All are welcome as I'm here to learn. As a little background I can rebuild/repair anything on the bike, 2 or 4 stroke. I can cut and grind but don't have access to welding equipment so that would have to be outsourced. Thank you in advance!

[mxdogger]

the crf450 frame is to long in the engine bay front to back, you will probably have an issue with the exhaust header reaching the motor with out hitting the frame. Im currently working on a 2008 crf250 frame with the 1997 cr250 motor, to get the motor positioned right a lot of material must be cut from the cast part of the frame.
From what i have seen with some euro builds the gen 5 (2010-2013)crf250 frame is the way to go, it has less clearance issues.

[317]

So it's probably in my best interest to acquire said 2004 CR250 frame and build off of that. I don't mind a Gen 3 frame, especially if it's going to be easier to swap and turn out better in the end. The nice thing is that almost everything else will swap over without too much trouble.

Thank you for your input. All other comments are still welcome!

[cmotodad]

What is going to happen to the rest of the steel framed bike? I want to build a steel framed CR with some twists. Let me know.

[gregrobo]

why would you really want to change out the frame unles it was completely shot the 1996 cr250 was one of the best handling bikes going round

[317]

What is going to happen to the rest of the steel framed bike? I want to build a steel framed CR with some twists. Let me know.

The rest of the bike will be parted to fund the project. I'll send you a PM. Thanks.

[317]

why would you really want to change out the frame unles it was completely shot the 1996 cr250 was one of the best handling bikes going round

The suspension is dated and I'm used to riding the AL framed bikes.