02 CR125 Clean up

Before I rode it, I wanted to give it a quick check over and try cleanup the exhaust a bit. It has a stock pipe with a PC shorty. 
When I removed the pipe, there was oil dripping out, this was a sign of what’s to come. The front of the motor was covered in oil and dirt. 

Opening up the muffler, the packing was soaked with oil soo I gave it a good clean and replaced it.

I threw the carb in the ultrasonic cleaner and replaced the breather hoses. 


Aside from needing a good scrub, everything looked ok to be able to go for a quick ride. I went to the local track and when trying to warm

The bike up, it felt like it wouldn’t clear out. I hadn’t ridden the track I went to for around two years so I wanted to take a sight lap. The bike was bogging so I tried to clear it out on the straights, but it eventually stopped. I put it down to idling around and fouling the plug so I pulled in and got a fresh plug to try. 
I got around 2 minutes before I had the same issue and only had the one spare plug. I tired cleaning it up but couldn’t get spark so that was the end of my day. 

When I got home, I got the bike started and noticed aside from being smokey, it was spitting oil out of the exhaust. The packing was wet again after only a couple minutes of run time. 

I drained the oil and noticed there wasn’t as much as there should’ve been and the oil that did come out had plenty of fuel in it. Looks like the bike needs crank seals. 

This post is now bringing us up to date. I’ve owned the bike for at least 6 months but life and some other jobs have gotten in the way (and I brought a 13 CRF250 to ride in the meantime). 
Now that I can ride the CRF, I thought I should tear down the CR125 properly so I have brought a complete seal and gasket kit as a starting point and will replace whatever else I find while I’m in there. 

A couple years ago, I made a vapour blast cabinet and I also have a sand blast cabinet and powder coat and cerakote setup in my shed that I haven’t really used much so I thought this could be a good project to try some of them out. 

Definitely doing crank seals. Currently debating whether I’ll split the cases and change out the bearings while I’m going. 
I’ll check the carb again, I just brought a jet block gasket. It’s currently got stock jetting. 

Before I could start tearing the bike down, I have recently changed my shed layout so I needed to move my lights to accommodate it. I really should just buy an extra batten light but moving them both around seemed to work and gave my a light above the bike and my main work bench. 
I removed the lighting kit and made sure to take plenty of photos/videos and label the cables. 
The airbox was surprisingly clean but I think that’s because I cleaned it when I first went over the bike. 
All fluids are drained and I’m hoping to be able to find time ti take the motor out tomorrow and maybe start cleaning the frame.  
This is where the bike stands now. Notice the oil all over the rear brake. I think it was run for a while with bad crank seals. The swingarm looks ok because I cleaned it before the first ride. 

I was able to get some time last night to take the motor out. Thankfully the swingarm pivot bolt was greased up and came out with ease. I’ve got everything off except the forks and haven’t had any issues with stuck bolts or any serious corrosion. 

Had some time today so tore down the rest of the bike. It’s definitely been cared for along the way, it didn’t have a single seized bolt and all bearings had grease, the head stem bearings looked new. 
I still need to do a bit more but I gave the oil soaked rear wheel and swingarm a quick clean in along with the frame. I just used some degreaser and a garden hose on everything then went over the frame with some mag wheel cleaner and a brush, then another go over with the mag wheel cleaner and scotchbrite pads. Came out good enough for a rider but I’ll give it another hit with scotchbrite and WD40 before reassembly. 

Got some time to scrub some parts. Removed the chain guide and slider from the swingarm and gave it a once over in the parts washer. Removed the steering stem from the lower clamps so I could remove the casting lines and prep them for coating.

 Pressed out the linkage bearings, but had issues with my bearing puller so cheated and just removed the rollers from the link arm bearing and left the bearing outer installed.

To try remove the casting lines faster than just a file and scotchbrite, I tried a flap disc on a grinder the get the casting lines close and finished them off with a sanding wheel in a dremel. It was much faster than my previous method but easy to take too much off. Usually I would spend a lot of time going over these with scotchbrite but as I test, I then put them in the sandblaster without any extra prep. I blocked the openings for all bearing races, but still had to spent some time cleaning out sand, particularly in the bearing on the linage arm. 

Plan is to coat them tomorrow. 

I brought supplier to powder coat and cerakote years ago but life got in the way and I’ve only used the powder coated once and the cerakote kit was still in the box. As a test for these I decided to go with graphite black cerakote. The idea for coating the linkage was mainly for ease of cleaning. 
I probably rushed a bit to get it done in the afternoon and didn’t plan out my parts hanging for the oven rack to well so I didn’t end up with a couple small spots where the clamps bumped each other and removed the coating when moving them to the oven. I had only mixed up 39cc of cerakote so I didn’t have anything left to touch up as I used a fair bit trying to dial in the spray gun. 

I would definitely recommend spending more time that I did on surface prep, but overall they came out ok and the high resonating paining works well. 

Got some time tonight to get some bearings back in the linkage and got it bolted onto the frame. Also peeled the sticker off the swingarm and gave the sides a two minute rub with scotchbrite. It really doesn’t take much to make a difference. 

Got the triple clamps on and put the forks in so I could torque the clamps. The forks don’t leak and have SKF seals so I don’t plan on doing anything to them. I will do something about the fork guards though  

Got my DIY vapour blaster running for the first time in a couple years. To check my media ratio and pressure was right I spent about 30 seconds on one of the motor mounts. 

I got lucky and it was pretty much dailed in first go so I decided to do some other parts. I actually left the brakes assembled since vapour blasting is much lower pressure and fine for the rubbers and plastics. They’ll need a good clean to make sure there is no media left anywhere before they get used. I also left the pads in to protect the pistons. 
Before:

After 

The plastic is obviously still yellow but it’s much better. The brakes were about 5 minutes each so I decided to do the subframe. That took closer to 25 minutes. 

Overall I’m stoked with how they came out for the limited time it took. You could definitely spend more time to get them perfect, but for a rider, this looks good. 

Got a few more parts vapour blasted today. Need to fix a few leaks around the glass in the cabinet but otherwise it’s working well. 

Since the blaster was setup, I decided to blast the entire motor. I had been tossing up whether to do it while it was together and since I’m pulling it apart anyway, I’m not concerned about any media getting in the motor. I thought it would be interesting to see how well it seals, so I did buy some effort into taping up the coolant outlets and any other openings. 

To my surprise, when I started pulling the motor apart, I didn’t find any glass beads expect for the stator cover which I hadn’t sealed well enough. I still don’t think I’d blast a motor that I wasn’t planning to disassemble. 

I didn’t spent much time in the cylinder or the side covers as these are easy to do separate. I mainly focused on the centre cases. This took just under an hour but if you wanted a show bike finish you could easily spend 3+ hours on the motor. 

The further into the project I get, the more it seems like a genuine low hour bike. Everything has come off easy so far and the hardware inside and out of the motor looks like it had never been touched. Head and cylinder are in excellent condition. No up and down movement on the crank. 
This is where it sits now. 

Tanks for the tip. I’ll look into the power valve seal. Not sure on the guards yet, but it’s good to know. The yellowed plastic does make the bike look old

Dug up my old powder coat setup to give the shock spring a birthday. It was in good shape but I just wasn’t a fan of the yellow. 
I didn’t setup my booth properly to hang the part so I made it work with a couple blocks of wood and an oven rack. 

After I was done, I noticed a couple spots that were a bit light on for coating so I’ve sandblasted it again and will recoat it next week. I did like how the gloss black came up but I was was thinking white could be cool. Not sure if the white would look good after a few rides though. I’ll get the booth sorted before I coat it. 

Forgot to take photos but I sandblasted and the shock spring and powder coated it again. I stayed with gloss black. 
I also split the cases and they came apart super easy. 

It really looks like a low hour bike. The bolt for my crank remover/install tool wasn’t long enough but I was able to throw the case half in the oven for 15 minute and knock it out with a rubber mallet. I used the same process to remove all of the bearings. 
Plan is to cerakote the cases tomorrow. 

I degreased the insides of the cases and left the vapour blasted finish as the surface for powder coat. 

I wanted to use combat grey cerakote but I noticed it was the only colour I had where the bottle wasn’t taped. All other bottles were shipped with tape around the lid. 

The solvent had flashed off and even after shaking for a few minutes, the cerakote was thick and the unopened bottle was around half full. I wasn’t sure if I should try thin it out with acetone so I just swapped to the tungsten colour instead. 

I mixed up 90ml and had some leftover so I decided to coat the engineer hangers and shock collars. 

As everyone knows, it’s not always smooth sailing, I thought I’d finished for the day once the parts were in the oven to cure so I turned off the lights in the shed and the power point next to the light as a force of habit.

 It wasn’t until two hours later when I went back to the shed to turn off the oven that I realised I plugged the extension cord next to the light switch into the oven because I had used its power point for the compressor. 

I treated this as an extended ambient cure and set the oven up again. Another two hours later and luckily the parts came out great.

Thanks. I’m stoked with how they came out, especially since it wasn’t my first choice of colour. I knew I wanted darker but not black and these should look awesome once it’s built. 
I’ve got a seal kit so now just planning to order some new bearings since I already have it apart, then I can start the rebuild. 

Didn’t have much time tonight but I was able to get the both wheels fitted and bleed the rear brake. Got the shock installed too. I haven’t decided on bars yet so front brakes haven’t been mounted. 

I also had a thought that it would be interesting to see how this motor runs with my spare HPP cylinders but I think I’ll try it stock first