Anybody ever swap a 230 engine to another frame?

[achildofthesky]

I've had fun on my 203 and really enjoy the engine. About as durable as can be and so far more than adequately powerful for most any reasonable sort of things. While the stock chassis is good enough for it's intended purpose, I am wondering how the little lump would be in a better frame.

Mebby something like an few year old CR frame or the like. Yea, I know good money after bad, but I am really intrigued by the idea and intellectually prefer the thought to spending a bunch on forks and shock and still having a smallish basic frame and drum brake with that lovely little engine.

It doesn't seem too hard to find ragged out or blown smoker's of fairly recent vintage for not so big bux. Some pretty good handling framesets out there that could work. Anybody done it yet? I am not talking of the BBR type kits, though nice, they are still mini sized frames. Let's roll the idea around and see what comes up...

Thanks in advance.

Patty

[ebeck]

Yep people have put in in a Gasgas 250 and at least several CR250 aluminum frame bikes.

I am putting a KDX motor in a KX as we speak. The proces is the same. Cut or shim the rear motor mount for the swingarm diamater, bore the rear motor mount for the Swingarm pin, make line up and weld on the other 4 motor mounts.

Modify the head to remove the un-needed motor mount is needed(it gets in the way) and shape the tank for clearance.

Good luck!

[Toast]

Patty,

All good thoughts. If you're too big for the frame especially.

If the 230 fits you than it's probably easier to get a Works rear shock & mod the existing forks or put some 125 MX forks up front with a travel stop & some tweeks to the valves.

[achildofthesky]

While I can ride the stock framed bike just fine, it is a bit cramped. I have a set of 46mm Kayaba's off a YZ426F I parted out and the wheels and brakes too. I may still do the mods to the stock chassis.

Hope you all realize that my wishes were'nt a slight to those that have modded the bikes. Bikes like that done by Ebeck and many others are simply great and have served as the INSPIRATION for me wanting to do an frame/engine swap.

I am darned near 6' and fairly "generously" proportioned (guess I should say a fat a$$) and would like to explore the CR/CRF frame set route and it might even turn out lighter to boot. A potential weight saving area is in the fuel tank. I wouldnt need much more than 1 1/2 gallons or so as the bike is thrifty to a fault in fuel burn. Having the CR/CRF frame set also solves the rear brake shortcomings and the seat height of a CRF isn't to the moon like some others. Besides, I like shiny stuff so the alloy frame has appeal. I must have been a crow in another life. I also like GG ergo's and acknowledge that could be a path to take as they often can be had for not too great money.

Please feel free to either post links, pix or PM me. I would be very greatful for all input and ideas.

I do like the idea of 2 bikes (have 3 now) but am currently planning on a 200 KTM XC or GG 200 for a snappy sometime race and the CRF230F (her name is Trixie) for general hooliganism and woods stuff...

Thanks again for the space and please keep the ideas and comments flowing. Let's see what we can come up with...

Patty

[Owyhee]

I've had fun on my 203 and really enjoy the engine. About as durable as can be and so far more than adequately powerful for most any reasonable sort of things. While the stock chassis is good enough for it's intended purpose, I am wondering how the little lump would be in a better frame.

I'm working on a CR500/XR200 swap. The CRF230 engine takes up roughly the same space as XR200 motor but is about 15lbs lighter (no starter, battery, extra starter gears, or wiring harness).

There are dozens of CR500 frames sitting around from people robbing the motors to make CR500AFs. I got a 1995 CR500 with everything but the motor.

The 500 frame has some advantages over some CR125/250 frames as the engine space is larger and mounting an XR/CRF motor doesn't require cutting the frame. It also allows for more space between the carb and the airbox. This is VERY important as your carb may be on the opposite side of the airbox that comes with your rolling chassis.

Swapping motors is very difficult. Aside from just making sure the engine will fit, there are other things to think about like:

1) Did the rolling chassis' swingarm pivot in the motor? What will pivot there now that the new motor can't support the swingarm?

2) Does the carb and airbox boot line up? Are they the same diameter?

3) Is the countershaft aligned with the chain with the engine centered in the frame?

4) Will the header clear the frame's downtube?

5) Is the rolling chassis' petcock lower than the carb?

6) Is the countershaft and rear sprocket the same pitch?

7) Who will make an exhaust system?

8) Which cables will work with what items?

Also, I got lucky that my rolling chassis also needed a fork set and I happened to have a set of freshly rebuilt set of 1999 XR600 forks sitting around. In my opinion it's silly to put USD forks on a 200 or a 230. It's complete overkill for such a weak motor. The XR600 forks are super beefy but easy to dumb down for the 200 and much more plush at XR200 speeds.

Any conversion is a money pit. That being said, it's also a lot of fun.

And P.S.: If you do end up getting a CR500 for a conversion and need a lower seat, I'll trade you my heavily dished seat and a new seat cover for your stocker.

"O"

[Toast]

Nice breakdown!

Yes, the air box could be a tough one.

[Owyhee]

Nice breakdown!

Yes, the air box could be a tough one.

I've seen some pretty slick XR200/CR80 swaps. Talk about a tight squeeze. Most of the swaps use a pod filter.

I had a pod filter on my old Maico MC400. Pod filters and water don't get along. Maico bottom ends and water don't get along. Maico top ends and water don't get along.

"O"

[ebeck]

Nah the air box is easy. There are several ways to do it but one way is to use the stock air box from the donor bike. Then remove the boot. Fab a plate to completly cover the boot mount measure and cut a new hole in the plate and and mount the CRF230 boot to that plate with the newly located hole. I'll bet you can just use an air box from an XR250 though.

Swingarm is easy too. Here is a drawing of what I had to do. Notice the material on the inside of the swing arm in the drawing and notice it installed. I had to cut 18mm of the inside of the swingarm to fit around the motormount on the engine case. It is just space in there, the bearing which is the load bearing surface, is completly unaltereed as you can see in th graphic. I also had to ream out the swingarm bolt hole 2mm.

Then, I removed the front motormounts. I then lined up the rear motormount/Swingarm and the head stay as in the pic. Once you have that you can create templates for motor mounts. Do th same for the bottom motor mount. I just cut andground them off today.

Gas tank can be molded with a heat gun.

An XR400 motor can go into a CRF250 chasis so I am sure the 230 can go it. In fact thre is guy out here who put the 230 motor into his 2000 CR250. It went right in as I recall. Ahh here it is... I see no tank petcock issues and thre is rnough room. the rear swingarm centers the motor as you can see in my picture above. Just take it all to a machine shop and they will measure and cut it exactly right. Really a swap is fairly straight forward if you engage a machine shop to tdo the cutting and welding.

Here is what hee said....

"I'm 6'1" and a tad over 200lbs. The CRF450 chassis fits me perfect and compared to the XR200 suspension....well, there is no comparison! I do agree a tad bit more power would be nice, but 80mpg and rock-solid reliability are strong points.

Would be hard to figure out my cost, as I had most all the stuff sitting arond here and our scrounged up and MacGyvered whatever else I needed! I would estimate costs all together to be under $2000."

[achildofthesky]

Right index finger tapping the tip of my nose and other hand wagging in the air with vigor "now that's what I am talking about!!!" Affix a light set up and that is EXACTLY what I envision...

Ebeck thanks for the visual. That bike would be a great fit for me. Was the donor chassis a CR250 or a CRF450?

Thanks

Patty

[ebeck]

It was a CF450F donor.

[Owyhee]

Nah the air box is easy. There are several ways to do it but one way is to use the stock air box from the donor bike. Then remove the boot. Fab a plate to completly cover the boot mount measure and cut a new hole in the plate and and mount the CRF230 boot to that plate with the newly located hole. I'll bet you can just use an air box from an XR250 though.

-snip-

Then, I removed the front motormounts. I then lined up the rear motormount/Swingarm and the head stay as in the pic. Once you have that you can create templates for motor mounts. Do th same for the bottom motor mount. I just cut andground them off today.

Gas tank can be molded with a heat gun.

I brought up a list of those issues because some may pop up depending on which donor chassis is available. Those are the issues I found on my CR500 frame which I believe will be even easier than CharlieT's CRF450 conversion (he had to cut the frame to clear the pipe).

My biggest issue for the XR200 install is going to be the airbox boot. The CR500's shock is offset about 1.5" right of centerline to clear the old airbox boot. The space between the shock and the frame is only 1.25 inches at its widest. Right now I'm thinking of using a slice of radiator hose going around the outside of the frame of making a u-bend like a sink trap to go over the frame's rear crossmember and up into the airbox.

Like it or not, where the swingarm passes though the frame is stuctural. The engineers did it for a reason. Like you, I'm just going to cap it off and call it good. In my mind, the new engine is 1/4 of the power of the old one and the bike's frame won't be stressed enough with the lawn-tractor power of the new motor to wear the swingarm bearings out too quickly.

Before I got my CR500 roller a guy at work tried to sell me a 1993 RM125 with no title for $500. I took out the ole tape measure and found that the top frame crossmember was about 1/4 too low and would be in the way, the petcock was 2" lower than the carb's float, the rear of the motor hit where the swingarm passes though the old motor, plus the motor's center to DS sprocket was 3/4" too big.

For me, this project is more about doing things on the cheap than getting it done quickly. I am allowed only 2 bikes, this swapped bike will be my third. I do not have any power tools (I got rid of them when I moved to Europe in 2002) so I have to beg/borrow/steal any machine shop time from friends.

Hopefully my donor motor will arrive next week ($150, eBay, runs!) and I can get things mocked up and take some pictures by the end of the month.

"O"

[ebeck]

Someone out here put the 230 motor in a blown GasGas125 as well.

You have good points there. The donor rolling chasis is everything. It can make it easy or it can make it hard.

As far as fittment, I know a guy who used a 1994 KX125 airbox with a KX frame KDX motor swap like I am doing becasue the 99 airbox was way off. I went forward in time and tried a 2000 airbox and it fit with no problems.

Another guy did a KX frame with a KDX motor and used a Gasgas 250 exhaust pipe. It fit perfectly.

The point is there are parts somewhere that will fit even if it is from another bike. Heck Yamaha races and bearings will work with the Honda frames for inverted forks.

I read a guy who put KX125 forks and clamps on his CRF230.

You airbox sounds tricky though. You can always make an airbox out of aluminum and a rivet gun and some sealant. Then you can locate the base of boot where you need. You still have the narrow passage for the boot to carb though. Old radiator hose would not be a bad ida. You can dress it up with nylon braiding from a hot rod store. Kind of like stainless steell but it is nylon.

That is what is nice about perimiter frames. No top frame bar. A heat gun and the tank can be bent out of the way. I had to cut off the 2 inch by 2 inch rear head stay as you can see below. Then it was just plastic molding. I guess don't be affraid to cut is the moral here, just man it togethter and ask alot of questions.

[Owyhee]

Beware!

XR200 motor + CR500 frame = headaches

The carb will be where the frame is, the petcock is 5 inches lower than the carb, and the tank is five inches too big for the head.

Everything else looks okay (kickstarter will only swing 75 degrees, header contacts the frame, etc).

No room at the inn!

Looks good from a distance!

"O"

[657pinkKTM]

i think i heard of a xr200/crf250 engine/frame swap...but that wouldn't be much of a difference would it. theres also a person who did a crf230f to x conversion, the bike is sick.

[Blueleader]

Nah the air box is easy. There are several ways to do it but one way is to use the stock air box from the donor bike. Then remove the boot. Fab a plate to completly cover the boot mount measure and cut a new hole in the plate and and mount the CRF230 boot to that plate with the newly located hole. I'll bet you can just use an air box from an XR250 though.

Swingarm is easy too. Here is a drawing of what I had to do. Notice the material on the inside of the swing arm in the drawing and notice it installed. I had to cut 18mm of the inside of the swingarm to fit around the motormount on the engine case. It is just space in there, the bearing which is the load bearing surface, is completly unaltereed as you can see in th graphic. I also had to ream out the swingarm bolt hole 2mm.

Then, I removed the front motormounts. I then lined up the rear motormount/Swingarm and the head stay as in the pic. Once you have that you can create templates for motor mounts. Do th same for the bottom motor mount. I just cut andground them off today.

Gas tank can be molded with a heat gun.

An XR400 motor can go into a CRF250 chasis so I am sure the 230 can go it. In fact thre is guy out here who put the 230 motor into his 2000 CR250. It went right in as I recall. Ahh here it is... I see no tank petcock issues and thre is rnough room. the rear swingarm centers the motor as you can see in my picture above. Just take it all to a machine shop and they will measure and cut it exactly right. Really a swap is fairly straight forward if you engage a machine shop to tdo the cutting and welding.

Here is what hee said....

"I'm 6'1" and a tad over 200lbs. The CRF450 chassis fits me perfect and compared to the XR200 suspension....well, there is no comparison! I do agree a tad bit more power would be nice, but 80mpg and rock-solid reliability are strong points.

Would be hard to figure out my cost, as I had most all the stuff sitting arond here and our scrounged up and MacGyvered whatever else I needed! I would estimate costs all together to be under $2000."

Hi,

I have a donor CRF450 chassis and XR200 motor, and I am starting this swap right now. Sure could use a "leg up" on some issues such as the air box, the engineering on the swingarm spacer/rear engine mount being used etc.

Do you know how to contact this person?

[naturaledge]

Hi,

I have a donor CRF450 chassis and XR200 motor, and I am starting this swap right now. Sure could use a "leg up" on some issues such as the air box, the engineering on the swingarm spacer/rear engine mount being used etc.

Do you know how to contact this person?

Hey Blueleader, I believe the guy that did that swap was TT member "Charlie T". Another guy on here who has done some awesome projects and is very knowledgeable is Ebeck. Good luck with your project and keep us posted. N.Edge

[ebeck]

I am absolutly certian that motor in the CR500 /CRF230 can be lowered but it will take making new mounts and the head stay cann be ground quite a bit. On my KX/KDX conversions I had to make new mounts and got the engine really low.

[ebeck]

If anyone ever needs help with a project or just want to bouce ideas off someone ar tallk about how to address an issue with conversion like ari boxes just PM me.

[coeshow]

Ther is another similar CRF250/230X conversion out there too. I have been aiding a man peforming the same deal but he started with a CRF250X. He states that the bike will be noticeably lighter with the 230 engine mounted. He weighed everything and says that the 230 engine is lighter than the 250 engine and radiators by some # of lbs.

For the type of riding he enjoys the 250 engine didn't cut it for him. No low RPM torque and tall low gear ratio.

He claims he was always slipping the clutch and/or stalling the engine when riding in his favorite areas. He liked the chassis and handling but NOT the power delivery.

He is still finalizing some items but I'm certain it will be a sweet bike when finished. It should look very similar, but will still employ e-start only.

It is important during engine positioning that the countersprocket is located in a fashion that will keep the chain from dragging the top of the swingarm as well as aligning with the wheel sprocket. Keep this in mind when locating the engine in another frame. While the engine as a whole may be positioned lower in the frame, the counter sprocket location in relation to the swingarm pivot and height is vitally important as well. The CRF230 countershaft position isn't optimized as well as current competition bike engines mostly because it is such an old design!

Most true competition bikes have the counter sprocket located as close to the swingarm pivot as possible for numerous reasons.

Good luck and ride safely.

[CharleyDarwin]

With a little bit of welding and a lot of redneck engineering, my uncle and I put a crf 230 engine on a KX 250 frame. The bike was the perfect balance of trail power and racing suspension.