CRF 230 parts in a 200x?

[mullet_boy]

So I stumbled upon a little peice of information that the crf 230 motor is designed after the mid 80's xr/atc 200 motors. After looking at some online microfiche of an 84 200x and an 04 crf 230 side by side, the similarities are amazing. So this got me thinking, the 230 makes the extra displacement up with stroke. I'm not sure how exactly the extra 30cc's gets in there, but I'm thinking with a few of the crf parts in a mostly 200x motor, you could have a 230x.....Anyone have some thoughts on this? (and yes, I know I could just send it to powroll and have it stroked)

[Yamada]

http://www.bikez.com/motorcycles/honda_crf_230_f_2005.php
General information
Model: Honda CRF 230 F
Year: 2005
Category: Enduro / offroad
Rating: 77 out of 100. Show full rating and compare with other bikes
Engine and transmission
Displacement: 223.00 ccm (13.61 cubic inches)
Engine type: Single cylinder
Stroke: 4
Compression: 9.0:1
Bore x stroke: 65.5 x 66.2 mm (2.6 x 2.6 inches)
Fuel control: SOHC
Ignition: CDI
Cooling system: Air
Gearbox: 6-speed
Transmission type
final drive: Chain
More details Consult a Honda repair manual.

200x
Engine type 4 stroke, Air cooled
Displacement 192cc
Bore x Stroke 65 x 57.8 mm
Compression ratio 9.6 to 1
Compression 142 - 170 psi
Transmission speeds 5 speed
Clutch Type Manual
Oil Capacity 1.3 Qt
Carburetion 24 mm Keihin
Starting system Kick Starter

The bore x stroke of the 200x is 65 x 57.8 mm
The bore x stroke of the crf 230 is 65.5 x 66.2 mm
Your right by saying the extra displacement is due to the longer stroke.
Would be fun the see the differences between the two cylinder and head.

[mullet_boy]

I was sure the extra was in the stroke. I'm just not sure how exactly there getting it. I mean there are a few ways I can think of they could be getting it, longer rod shorter piston with the same jug height as the 200x, diferent crank pin placement and a shorter rod with the same deck height piston and same height on the jug as the 200x, or maybe its just a plane out taller jug to fit that extra stroke. I read that the 230 will fit right into a xr 200's home though, so im assuming its the same overall height roughly as a 200...I also read about someone putting a couple diferent pistons (yamaha i think) in an xr, 70mm and 68.5, and if i remember correctly the 70mm with a bit of a stroke put it at 250cc's. If any one out there has a crf 230 id be very interested in the dimensions of the motor, as I can't seam to find them on the net..

[oldskool83]

not a drop in like a xr200 motor...gotta carry a battery also. go XR200,,,way more parts

[mullet_boy]

What I was refering to about the 230 fitting in place of the 200 was more size comparison than wanting to acctually put one in my trike. Since they are the same size(from things I've read I don't acctually know) that would mean the jug is the same height and the diference would be in the crank/rod. I'm hoping to mix in some 230 parts in my 200x motor and get a stock appearing stroked motor for less than one from powroll. Hopefully with a larger bore maybe, even one larger than they offer.

[saleen_n_around]

What about 86 and 87 200x's......they went from 192 cc in 85 to 199 in 86 and 87. How did they pick up the extra CC's>

[deathman53]

a totally different motor, almost everything between 83-85 200x and 86/87 200x is very different. Forks, handlebars and maybe some small parts are the only thing that is close.

[mullet_boy]

deathman53 is right, its a diferent animal. I'm pretty sure they were 4 valve, instead of 2, and 6 speeds. I think they had a bit more power too....Anyways, does anyone have an idea as to where I could find out rod journal sizes, rod lengths and that sort of stuff for the 230, and the 200x?. I suppose I would need piston heights too...I was thinking maybe chat with the parts man at my local shop?

[69HemiGTX]

The extra stroke only comes from the location of the rod journal. It is farther from the centerline of the crank on the 230F than the 200X. The rod length has absolutely nothing to do with stoke. The rod could be a mile long, but if one end moves up and down an inch, what do you think the other end is doing? It's moving the same amount. Always has, always will. Now, with a longer stroke in a given deck height, the rod length and/or compression height will have to change. Deck height is the distance between the crank centerline and the head gasket surface, and compression height is the distance between the wrist pin centerline and the crown of the piston. I would imagine that Honda just stroked the crank and either shortened the rod a little or brought the wrist pin up a bit to compensate, or they may have done a combination of both. To avoid any confusion, here's a rundown of why:

Let's say that the piston is zero decked, meaning it sits flush with the top of the cylinder at TDC. If you stroke the crank, say 0.100, the piston will pop out of the bore by 0.100 at TDC unless you change either the rod length or compression height. If you shorten the rod by 0.100, you can run the same piston as before. If you want to run the original rod, then the piston's compression height will have to be shortened by 0.100. Of course, both parts can be altered by any amount so long as they add up to 0.100 shorter than before.


Several factors need to be checked to verify this swap, but these need to be equal for both engines:

Deck heights
Cylinder head bolt pattern
Crank wheel diameters
Crank bearing diameters (OD) and widths
Gear spline counts or pitch, width, diameter, and tooth counts of drive gears for clutch and cam chain
Stator snout length, diameter, taper, and woodruff key location

Just make sure to get the right rod and piston for the 230F crank, and make sure to over-bore the 200X cylinder (if stock) since the stock 230F piston is 0.5mm bigger.


Being that it costs a lot of money to make major changes to any engine, I'd venture a guess that only the crank, rod, and/or piston are different for the 230F. It just makes economic sense to change as little as is necessary to achieve the end result. Yeah, the factory bore is 0.5mm bigger vs. the 200X, but you can easily bore the 200X cylinder.


BTW, a 70mm piston with the 230F's crank nets 255cc, but you need to make sure the sleeve can actually be bored 4.5mm over (+5mm for a 200X). If it's possible to bore the cylinder that big and stuff a 230F crank in the 200X cases, then :naughty:

Here are some interesting numbers based on the 230F crank (rounded):

65.0 x 66.2 = 220cc
65.5 x 66.2 = 223cc
66.0 x 66.2 = 227cc
66.5 x 66.2 = 230cc
67.0 x 66.2 = 234cc
67.5 x 66.2 = 237cc
68.0 x 66.2 = 241cc
68.5 x 66.2 = 244cc
69.0 x 66.2 = 248cc
69.5 x 66.2 = 252cc
70.0 x 66.2 = 255cc

[mullet_boy]

Hey thanks for all the info on that. I'd have to agree they probably didn't change a whole lot to get that stroke, wich was my whole basis for checking it out. If they didn't change a whole lot, it wouldnt take a whole lot to fit it into a 200x. The great thing about this is, I have a boring bar, and I can get Wiseco pistons at cost from a shop here in town.(I bored my current set up myself and bought a 12:1 for $75) So the only expensive part I'd have would be the crank/rod and what ever else I would need from the 230. And of course the many hours of head scratching to get the thing together...but hey thats half the fun right?

I just measured a jug I had laying on my desk from an 84 xr200, and it looks like 70mm bore would be out of the question, but 68 might be attainable.

[tri-Z ripper]

here try this site www.crfsonly.com

[mullet_boy]

Hey thanks! I didnt find any info readily available there, so I went ahead and posted asking if anyone had the info I wanted. Hopefully someone has the info i need on sizes there..of course then I'll have to tear apart the xl200 bottom end i have laying in my garage to get the sizes on it to make sure everything will fit. Time to break out the craftsman set and the vernier callipers....that is unless anyone here has that info on hand? Either way thanks to all you for the help and the many repllies!

[BigReds Forever]

This would be really cool if it would work. Or, if not, just put a whole 230 motor in the 200x. Another interesting thing is that the 230F uses a 26mm piston valve carb, while the 230L uses a 30mm CV. Just as an FYI on the 83-85 vs. 86-87 200x's. They are very different motors. The 83-85 uses a 65 x 57.8 mm bore/stroke, while the 86-87 uses a 65 x 60 mm bore stroke. So the extra few cc's are coming from a longer stroke. I HIGHLY doubt the cranks would swap. As far as other differences in the motor, its true it is a 6 speed, but it is only a 2 valve head.

[Louis Mielke]

Its been proven that the 230 will bolt into a xr200 and the xr200 will bolt into a 230 frame.

[mullet_boy]

Woops, I thought they were 4 valve heads. Thanks for catching my screw up on that, lol. I would just swap a 230 into my trike, but then I would have to carry a battery, and worst of all no kick start. (I dispise electric starts, especially electric only). Another problem I imagine I'd have is locating a dang motor. From what I've seen on ebay, motor alone was nowhere to be found. Of course if I did find one im sure it would cost too much anyway. I'm sure a crank for a 230f isn't exactly cheap, but cheaper than a whole motor. On top of all that, whats the fun in just dropping in a new motor and wiring harness and riding?

An interesting bit of info, powroll offers a 6mm stroker for $250. The crf stroke is 8.4mm longer than the 200x's.