83 YZ125 K Restoration

I'm looking for a good condition oem 83 yz125 expansion pipe and muffler still. They seem to be hard to track down.

If you guys come across something ping me.

Had one and sold it. I want oem.

Yes already have all them bits NOS. Thankyou however.

I've actually got an orginal pipe and silencer but it's had a hiding. I've given it to a guy I know to do some welding and bits on so will be interesting to see how it comes up.

In the mean time the search continues....

Here is the oem pipe after vapor blasting:

The area between the start of the expansion onwards isn't to bad, it's the area between the motor and start of the expansion that's coped a hiding..

Been a while since I've posted an update. The bike has been ticking along slowly still. The focus at the moment was sorting the pipe and silencer out.

I originally bought a DG pipe but then later sold it as I felt it wasnt with in my ideas of keeping the bike as orginal as possible.

I couldn't find the pipe the bike had when I was a kid, last time I seen it, it was in the shed at my parents farm. I searched every corner of the place 3 times over to no avail so maybe it got thrown out over the years when my parents done a clean up. 

Anyway I started searching around, reaching out to wreckers etc to no avail, but then a few days later one popped up on ebay USA. It was rough but cheap enough so I bought it anyway.

Here is the pipe when it left america:

The first thing was to vapor blast it all:

As you can see the section between the cylinder and start of the expansion has had a hiding.

From here I tried blowing the dents out but it had to many pin holes along the seams so I couldn't get it to hold pressure, so I gave it to a bloke I know to weld up:

You can also really see the pitting in the photo above. I tried sanding alot of it out and whilst I got it abit nicer I couldn't sand to much as these pipes are paper thin from factory, I'm guessing  to save weight and be throw away.

I then thought how to fix the pitting. Some ideas were skimming it with devcon, more sanding and risk making it weak and then getting it copper plated. I contacted a few platers and most came back with the same answer. " doubt we could deposit enough copper to fill it all"

At this point I was over it.. I decided to push on..gave the pipe another quick sanding over, decarboned it internally and took it to a local ceramic coater. Oh also the silencer was cut opened and repacked.

Here's the result: (just sitting loose)

Turned out okish.. not 100% happy with it but it's better than nothing at the moment.

I also have another pipe on its way to me thanks to a member of these forums that might be nicer... stay tuned.

Thanks Brad for bringing these goodies back from Adelaide for me and reaching out when you came across them.

The pipe has a few dents, which are easy enough to get out with air and heat. First step is to blast it and see what it's like underneath. Hopefully not as pitted as my current one.. 😬 

Been a while since I've updated this. The plan was to fire it up on Christmas day however an electrical issue prevented this.

Spent about 2 days trying to figure out the problem, testing coils, cdi, spark, removing carb, checking jets, float level etc to no avail.

I then had a light bulb moment where the only thing I had forgotten to check was the sparkplug cap/boot from the coil.

Turns out I had a bad connection here, easy 5 minute fix and she fired straight up.

Here's a little video of it running, sorry it's average hard to film and throttle etc..

Still haven't ridden it, going through the heat cycles atm and need so sort out a throttle cable..I'll explain more in the next post.

Cheers

Heat cycles done and onto the first ride today.

Didn't ride it hard as still running the motor in but she seems to be performing well. Selects gears nicely, throttle feels sharp, brakes working, clutch working etc

The smile on my face was ear to ear, the nostalgia of riding it again after 20 years was awesome.

I'll just leave this basket case here...

The plan with this one is to make it a dedicated rider, so won't be anything to crazy.

I hope..  

Update on the basket case. Ordered the following parts and received them today:

-front wheel bearing kit

-rear wheel bearing kit 

-front fork oil seals and dust boots

-fork oil

- Swingarm linkage kit

-lower chain guide

-Airfilter

The plan from here is to get all this stuff fitted and start assembling the frame side of things. 

Thanks, wasn't easy finding some of them NOS parts but the end result was worth it.

Small update on basket case build:

Supplier sent me wrong steering bearings, got the correct ones today so have started fitting them.

Realized I was missing the castle nut so have one on order.. baby steps.

It get's worse...Alot of my old parts I had sold to someone who was going to build that basket case I now have only for them to give up and sell it all back to me  

Worked out well in the end, I have so many parts for the K ill be able to build this one up fairly quick and cheap and have a dedicated thrasher so that my first one doesn't get ruined. 

Front and rear bearings and seals done on the basket case. They needed doing they were toast.

Next up when my bolt kit arrives is to fit the new 50 tooth sprocket up and then do all the swing arm and linkage seals and bearings.

Looking for a set of usable radiators oem only if anyone comes across something ping me.

Little more progress on the basket case whilst I wait for the final few parts needed to assemble the frame side of things.

Little more progress done. All the bearings have been done now in the rear linkages / swingarm and rear shock.

I really want to fully rebuild the rear shock but knowing about the dampener not having hard anodizing done back in their day I can almost gurantee it'll be stuffed and a headache. What are you guys doing regarding rear shock on the 83 yz125?

You are indeed correct regarding the hard anodizing. Most of the time you open them up and they're stuffed so you're back to square one.

I did have a quick look on the yss website but didn't see anything listed for the 83 yz125?

I'll take another look.

I sent them an email got a reply back saying nothing available for the 83 yz125k  

Decided to pull the front forks apart to inspect condition. Glad I did as one of the forks was missing a small part from inside. (Spindle taper)

Whilst apart I decided to give them a freshen up with new guides, seals, dust boots and oil.

Long live the yz! 

Eagle eye 

Whilst I'm waiting for some parts to arrive I've started thinking about what to do with the engine.

At the moment I'm thinking, full set of bearings, seals, gaskets, new rod, piston, ring, clutch plates, clutch springs and what ever else I find that it might need once it's opened up.

Had a sneaky little look inside this morning and this is what I found:
 

Dome area of the head looks mint.

Bore looks pretty good too. Measured it up and should be able to get away with a 2nd oversized piston at worse case or a hone everything being OK once it's properly apart.

Appears to have a set of aftermarket reed valves in it. I'm assuming they're boysen reeds.

Power valve linkage appears to be all there and OK.

Orginal carby has a little wear in the slide area. Probably be OK.