XR 650 R engine in crf 450 frame

Some experience about this?

I'll try and report.


Welcome to Thumpertalk,festerr, Keep us informed on your project,:confused:

And post some pics as you move along with it..:lol:


at first: i need an engine!

dude - why?

The XR engine is so much taller that you will butcher the frame - custom made gas tanks etc?

Great idea but the XR frame is already alloy, so why?

The alluminum frame on the XR650R is heavy. 12 pounds heavier then the XR600R. If you put the XR650R enige in a XR600R frame the bike will be 10 pounds lighter. If you could ever put the XR650R engine in the CRF450 frame or even the new generation frame that would be cool....if you can. It would be something different and would be a blast to find out how it would handle.

always looking for an engine.

is there something down there?

if u tried to do that u would end up with a slow , extremely bad handling, race /desert abortion machine lol . It will be a waste of your money and time not to metion you will be ruining a perfect bike???...i still dont know why u would want to put a 650 engine in a 450 ? i will put money on it that if you do this a stock crf450 will smoke this abortion in every aspect....just my thoughts ....your not and engineer

my xr 630 is an abortion for current ways to consider bikes, but i'm faster on it than on my crf 450 in tight enduro tracks, on stones and so on.

i'm not an engineer, but 15 years ago i put a 550 yamaha engine on a 1987 250 kx frame, and the result was astonishing.

stopped using this bike because of italian police, not willing me to ride it on the road!

well if there s a will there a way and it sounds like u know your way around a bike ...goodluck

If you can pull it off it will be the King of all Dirt Bikes!!!!

I apologize for my bad english, I 'll try to tell you what I think.

I reckon it is an interesting experiment but I am afraid the engine is too big and too heavy. The CRF frame is studied for a the crf engine.

I mean Honda projected both bike for a two specific purposes, I don't think mixing them you could get a better product, otherwise it would mean Honda's engineers would better go selling ice creams...

I think you may transform a XR understanding the original project and his weak points and then you may improve it.

For example the XR suspensions are studied for a "normal" pilot, if you are a fast pilot you may improve the bike changing them.

sorry everybody, i thought that my initial question was clear, i just asked if somebody tried to do this, hoping to receive some pictures and suggestions, but it's clear now that nobody ever made such a modification.

and i wouldn't like to be the first...


thinking about budget

i'll look for a used crf engine

and will overhaul it!

maybe transform it in a 490cc.

Answering to uncleroby: honda engineers maybe will not be selling ice creams, but sometimes they should be obliged to work in a real workshop!

So, in Italy I heard people talking in forums about such operation, but they changed their mind, I guess after making some measures of the components.

Uncleroby: I'am italian.

tomorrow i'll go to a firnd and put the engine in the frame.

than, i'll tell you.


If you put the XR650R enige in a XR600R frame the bike will be 10 pounds lighter.

And handle like you've taken 20lbs of metal out of the frame! The R frame is heavy in part because it's so STIFF. Stiff = better handling. Up to a point.

That actually sounds like an interesting idea if only for the fact that the ergonomics on the CRF are so much more modern then the XR's. If you're looking to make an XR powered bike that's significantly lighter then stock I think you'll be disappointed. The advantage of the XR engine is that it develops peak power at about 6750 rpm's as opposed to 11,000 on the CRF. You might want to contact Service Honda they build a bike that puts a CR 500engine in a CRF 250X frame and they will sell you a brand new XR 650R motor as well.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now