Project CRF

[greenhuman]

Most of my almost new CRF230F engine arrived today and the center cases were on the mill within half an hour.
1st stage. Trim off the front engine mount plus some to make room for the 16mm alloy plate. Note the little lump of alloy I had to leave on the L/H case so the stator cover will fit back on like factory original.
I made some discoveries today also. These CRF engines have inlet and exhaust valves 2mm bigger than the '83 -'85 ATC200X. 66 mm stroke is also a good thing along with the double roller cam. I will modify a serious 200X cam to run in the CRF head with a Jmc Racing port job and hi-comp forged piston.
I will be fitting a 200X 5 speed gearbox instead of the standard 6 speed plus I figured I can fit the 200X forward kick starter setup for a backup starting system. These things come from the factory with electric start only. I have searched a lot of CRF tech forums and have not seen this kickstarter mod done yet. Needle rollers for the shift drum are standard and the cam chain adjustment is cylinder mounted which is a bonus with this case mod.
I will post more images as the build continues.

[motoman1012002]

So im guessing this is goin to be a another laydown motor

[aproudcanadian]

you are my new best friend, ive got a crf230 engine in my 200x, the thread is atc230x if you have not seen. well i have been really thinking about trying to do the kick start conversion. also if you want some good pistons, cams or big bore kit check out coeshow.com best stuff out there for the 230's i will be following up on this. good luck

[shortline10]

Very neat stuff . Will be keeping an eye on this thread .

[Skydrifter350]

I will be watching as well. Got big plans for my 200x & this might be the direction I go!

[greenhuman]

Alloy plates welded in place by Mart (very good job,too)
Face off the centre cases and bolt together with a centre gasket and into the jig.
Started boring cases for the cylinder. 1/2 mm per cut out to 72mm. Stud holes, oil gallery and cam chain slot next.
I will finish these cases tomorrow and assemble the bottom end tomorrow night.

[shortline10]

Nice work !!! Putting that in a atc70 frame

[AutoXer]

or a 460 v twin!!! LOL your work is amazing .... who would have thought that a atc70 should have a 230cc motor in it

[greenhuman]

Here is the engine mocked up. No internals yet. I have found the 200X gearbox and the XR 6 speeds will not fit in these cases. It looks as though the Honda XL185s 5 speed will fit OK. The CRF cases are the same width internallly as the XL and the ATC/XR cases are wider inside. The CRF 6 speed must have really narrow gears to fit. This may be a weak point when fitting these engines in an ATC frame. Time will tell.

[aproudcanadian]

everythings looking great, that sucks that the 200x parts will not fit, what about the 03-05 crf150 i have heard they do fit, just not sure how the kickstarter would clear the frame or fender. also looks like L model engine, would the F models be different ?

[torker]

Isn't madness cool??? Amazing...

TORKER.

[NINJA]

Looks awesome! Can't wait to see the finished project.

[whitetail hunter]

awsome work!! any more progress?

[greenhuman]

Well, a Honda XL185s 5 speed gearbox and kickstarter gears fit as well as the stronger 200x kicker gears. The CRF conrod has to be modded to clear one of the gearbox gears much like the Powroll strokers.
More images soon.

[whitetail hunter]

how did it turn out? have you stuffed it in a 70 yet?