I have begun a project to move RM100 components onto a DR-Z125L. The RM100 is a 2003 model. Because of the marketing deal between Kawasaki and Suzuki, the RM100 is just a Suzuki version of the KX100. The DR-Z125L is a 2003 model.

Moving the forks over was so easy, that I didn't get any pictures along the way. Here is the DR-Z125 with the RM100 forks:






The swap of the forks took less than 2 hours. It was a direct exchange. I even put the DR-Z forks onto the RM. So, while the DR-Z is getting better, the RM is getting worse.

Next I will work on moving the swingarm. I'll be back with more pictures after I make some progress on that.

If you want to see some other conversions that I have done, try the CR80 & XR100 Conversion or the XR80 to XR100 Conversion.

I'd like to do this for my son's bike, keep us updated.

Did you swap the whole front end? (Wheel, brakes, handlebars)

I'd also like to know if the RM shifter will fit on the DRZ. The shifter on my son's bike is a piece of

knucklhead said:

I should have been more specific about what moved and what stayed. That third picture shows the new front end. You are seeing the top and bottom triple clamps from the RM. The steering stem (unseen) is also from the RM. The steering stem bearings are interchangeable, but I used the ones from the DR-Z. The forks are from the RM. The handlebar is aftermarket, but was from the DR-Z. The brake lever, brake line, front brake and front wheel are all from the RM.

Basically, the DR-Z kept its handlebar and all controls, except for the front brake lever. Everything else came from the RM.

I am working on a little machining to get the RM swingarm to fit. I'll post pictures when I am done.

Here are a few pictures from the beginning of the swingarm swap.
Here is the RM 100 with DR-Z125L front end and no swingarm.


Here is the RM 100 swingarm and shock.


Here is the DR-Z125L swingarm and shock.


The DR-Z125 without swingarm.


Beginning the fit up of the RM swingarm on the DR-Z.

YEAH!!!!!
Keep us posted. I can't wait to see how this turns out!!!!

looks good keep us updated i've been wanting to do this for a while i've got everything on mine but good suspension plus a rear disc would be awsome.

Can you please tell me what cutting and welding you have had to do for this swap? Please give me as much detail as possible. I have pumped about $3200 into my DRZ 125L project and the last mod is this conversion. I have done everything else imaginable.

Your last photo looks like you just bolted the swing arm assy from the RM to the DRZ but that is not the case.

Thanks!

MDSmith said:

That is, indeed, not the case. I was just trying an initial fit up. Here is more of the story on the swingarm.

Here is the first problem: the DR-Z swingarm bolt is bigger in diameter than the RM swingarm bolt. That is the DR-Z on top.


That means that the bearings on the RM swingarm are too small for the DR-Z bolt to go through. Either the RM swingarm mounts need to be made larger, or the DR-Z frame and engine mounts need to be made smaller. Also, the RM bolt is too short. So, rather than trying to make the DR-Z mount points smaller (which is pretty tough, given that they are holes), I chose to make the RM swingarm mounts larger.

I took the swingarm to a local machine shop and had them bore out the mounts so that they would accept the DR-Z bushings. Here is a picture after boring.


One thing I do not like is that the RM swing arm has bearings, while the DR-Z has bushings. Bearings are a better mount than bushings. But, sometimes you have to put up with tradeoffs in these projects. I decided to, at least, replace the bushings with new ones. I ordered an All Balls set. And what do you know... when it showed up it was bearings. Here is a picture of an original bushing and a new bearing.


I just pressed the DR-Z bearings into place in the machined RM swingarm using a vise and sockets, and here is the result. (The bearings still have some foam packing in them.)


Here is the RM swingarm mounted in the DR-Z.


I am using the shock linkage from the DR-Z.


So... here's what the RM swingarm looks like mounted on the DR-Z. This is not the final mounting, because I need to do a little welding to mount the rear master cylinder and I don't want the swingarm in place when I do that.


Another part of this project is engine upgrades. That is not essential when making these suspension changes, but it seems a bit of a waste of good suspension to not do them. Here is the engine without the head and cylinder.

What engine upgrades are you doing? Any carb mods to go along with the engine?Thanks for keeping us posted on this it's great.

We are not going to be racing, so the engine mods are not the most that can be done.

I bought a Wiseco 61mm, 11:1 compression ratio, piston which will increase displacement to 143cc. It was a little over $100.

The camshaft is being replaced with a Hotcams stage 1 grind.

The exhaust is already a BBR.

I had a Twin Air air filter, but went with a new UNI. The airbox has massive holes in it now. I will talk more about that later in the project.

The carb will be upgraded to a VM-26. I had one on a while back, but took it off because I wanted to limit performance for some newbies that were riding it.

Those are all the mods that I have planned, for now.

How much do you think the total price tag will be?

Do you need to fabricate spacers for the RM swing arm? It looks like there could be some side to side movement.

When you get a chance, can you measure the new seat height after the RM componets are installed? I'm wondering if my son is tall enough for this conversion yet.

Thanks for the posts

dr_drz said:

Just adding the Wiseco piston gave you 143cc? seems like a bargain. I have read your mulitple jetting posts...did the increased displacement require further jetting?

starrman said:

I changed the displacement, compression ratio and cam. I am guessing that I will need to rejet, but I am still waiting on the cylinder to come back from the shop from being bored out for the new piston.

I will measure the seat height when I am done.

I have not done the final fitting of the swingarm. The initial fitting says I will need a few washers for a good fit. I will give details when I am done.

I am in the middle of the rear brake master cylinder install. It is not simple. I will post pictures when I am done.

So the Wiseco piston isnt just a bolt-on upgrade? It requires boring the cylinder?

starrman said:

In order to increase displacement, either the stroke or bore must change. Changing the stroke involves crankshaft work. Boring is far less work, but still requires a machine shop.

Wiseco does make an identical size piston, as well as several intermediate sizes. I went for the biggest they have.

Thanks. I thought perhaps something about the piston's design would provide more open area in the cylinder, thus more displacement. drats.

starrman said:

Displacement is calculated as the area of the piston (pi x radius x radius) times the length of the stroke.

Compression ratio is the volume above the piston when the piston is at the bottom of the stroke to the volume above the piston when the piston is at the top of the stroke.

If the piston is made shorter, the displacement will not increase. The compression ratio, however, will decrease, generally not something you want to do in order to increase power.

The wiseco piston has a diameter of 61mm. That means that the radius is 30.5mm. The stroke (which is not changing) is 48.8mm. We usually want displacement in cc's, so we must use cm's rather than mm's. Thus, the new displacement is pi x 3.05 x 3.05 x 4.88 = 142.6 cc's.

The new piston is slightly taller than the stock one and increases the compression ratio from 9.5:1 to 11:1.

Thank you.

I used to own a dr-z 125 and the supension would need some more travel ,but the end product would be awesome. Kind of like th project on dirt rider where they put a xr200 motor in a CR 85 expert.