YZ125K Rebuild

[alexbrown64]

Thanks Tony.. i use photobucket to host the pics.. its a pain.  Heard your project is coming along too.  Glen is having some major dramas with his frame.  I was lucky, i got my dad to tig my frame up and i should be able to pick it up from South Side powder coaters this week.  The local guy was too dear.  Southside is blasting, undercoating and powdercoating in gloss black for $140.

Just had a setback with the monoshock.  Grant at Shock Treatment rang and said the shock is knackered.  They were not hard anodized internally and wear out.  My shock was blown when i got the bike so probably worn out (like the rest of the bike) for years.

I have just purchased three, yes three YZ125K monoshocks on Ebay.  All known working ones with damping.  I will give all three to Shock Treatment in the hope that they can make one fully rebuilt good one.  If they can make a good one up, they will hard anodize it.  Then they will send me back the rebuilt shock with gold valves etc, and the old shocks for spare parts plus my fork kit with emulators and new springs etc...

[alexbrown64]

Quick update:  Just got the frame back today.  Looks great in powder coat gloss black.  Also got all the hardware back in fresh zinc electroplating.  Now i am ready to start bolting a few bits back on.  Pics soon..
Cheers,
Alex

[alexbrown64]

Started the rebuild and first up was fitting the new steering stem bearings.  I froze a few things here and heated some other things there then bang, whack and it all went back together.
 
The swingarm took some time.  The anodizing was all scratched up, so i made a caustic bath and soaked it for a few minutes to get all the anodizing off.  Then a bit of sanding and a nice buff for a polished look.  The allballsracing swingarm and linkage bearing kits were fantastic.  All sorts of bearings, seals, bushes and bits and pieces and it all fitted up nicely.  I just whacked out all the old rusted and knackered seals, bushes and bearings.  Then i gave everything a light hone.  I pressed all the needle roller bearings back in using a 4" G clamp, large washer and various sockets. Everything was then fitted up using the newly zinc coated bolts and plenty of grease.

The tank was sanded back and Wicked Tough decals applied.  They are great decals and hopefully wont bubble off as i think they have worked out how to keep them on.  Then some Plastic Renew was applied to get a nice shine on the tank.

Southside Powdercoaters did a great job on the frame and it has come up super tough and like new.



Cheers,
Alex

[alexbrown64]

DC plastics arrived and they are not too bad.  I had the shrouds custom done in white.  Bolting up was a pretty easy process.  Cutting the slots to look similar the the Lechien OW125 took a bit more time and then taping them up and painting the number plate backgrounds.  Front and back guards were also fitted after a sand and buff with Plastic Renew.  I took a trip to Masters and they have 8.8 bolt kits with about 150 various size bolts from 5mm to 8mm for $25.  The only problem is that they have a dichromate yellow gold coating.  I soaked them for 30 seconds in vinegar and that removes the gold while retaining the zinc underneath.
Below is a pic of how the OW125 tribute bike is coming along.....




Cheers,
Alex

[Rossvickicampbell]

Alex - are you going to cut the side panels short?

[alexbrown64]

Hmm... i have looked into cutting them shorter but the design doesn't really allow it as there are thicker tabs at the front to keep it all nicely tight under the seat.  I cant make a replica bike but i have a theme going with a bit of poetic license. 

I had to repaint the number plates again today.  I rushed it the first time and put the paint on too thick.  It all cracked.  I used some paint stripper and washed it all off, sanded, cleaned and taped up then used some plastic adhesion paint followed by some satin black.  OK now.  I may get some nice sheets of thick vinyl satin black decal sheet later.  I also fitted the PVL coil and CDI and put the front fork tubes in to trial fit the new front number plate.

[alexbrown64]

Ive decided to log what bearings and seals go where in the K and also what size or type they are and what the Yamaha part numbers are.  Below are 5 pics of the cases with most of the information needed to help rebuild the engine on the K.













On a side note, a used cylinder, cylinder head and powervalve was purchased in the US.  This is being sent postage free to Forward Motion for Eric Gorr to resleeve and fit Wossner standard piston, port, machine the head and powervalve to suit and bead blast. Will be like an entire new top end but with the Gorr magic.

Cheers,
Alex

[alexbrown64]

Righto, some updates.  The cases in the picks with the bearing and seal descriptions are not mine.  I just used some photos from Ebay and then added all the text boxes and data.  My cases are rooted.  The clutch arm housing has been worn away and i have a major problem with the main bearings not being an interference fit.  That is a another thread.  I found another set of 83 cases on Ebay and Shane, the owner, trial fitted the mains.  He said they would not go in without heat etc.. so hopefully they are a good set.  The pics looked good.  Anyway, $110 including delivery so that is pretty good. He has popped them in the post already.
The cylinder is on the way to get resleeved.
The rear shocks, airbox, kickstart and a bunch of other stuff is in Hong Kong and should be here soon.  Then the shocks have to go to Shock Treatment.
Renthal bars ordered locally from Dave Langston.  He is also pricing up and looking at availability of Gold Excel Takasago rims.
Crank is in Witch Cycles.. should be ready in a few days.

Even though its Christmas/New year, things are moving.  My neighbor just popped round.  He is trying to weld up a 1989 YZ250 frame.  Having a bit of bother with it but hopefully he can get his frame off to the powder coaters soon.

Have a good New Year,
Cheers,
Alex


These are the actual cases i have purchased...
 

[alexbrown64]

Well, that was going to be it for the arvo as im taking the kids to archery and then off to the grandparents.. however, my decals arrived from the states.  In keeping with the Lechien tribute OW125 spirit, i made up some decals the same as on his rear fender.  I used http://www.stickeryou.com/2 to create the logos from ones i downloaded from the net.  I then edited them and made a few A4 sheets worth.  I also have some other decals i designed and added to the A4 decal sheets.  You can do most of the editing and stuff on their website.  Its not a bad website to remember as i created my custom decals, had them printed on vinyl to two A4 sheets and they only took 2 days to make them and posted them fast to Oz.  All up cost was only $25 bucks.
Pic below of them on the bike.
Cheers,
Alex

[BJJ]

Whata great project,  looks awesome

[alexbrown64]

Another quick update.
Trial fitting things up. Cone pipe and muffler fitted.  Will have to make a few small adjustments to the plastics as they touch the muffler.  I fitted the brake stay arm and used 2 sealed bearings instead of the spherical bearing and 2 seals that were originally in the front of the arm.
Wide footpegs fitted.
Cases should be here by the end of the week... crank is ready to be picked up from shop.
Cheers,
Alex

[80-85 husky]

spherical bearings are usually utilised to account for radial forces......have I missed something? will the std ones survive?

[alexbrown64]

I hope so.  I read somewhere that the brake stays on different brands can come with spherical bearings, bushes or roller bearings.  It only goes up and down a few degrees and i have put 2 heavy duty sealed bearings in there.
Picked up the crank yesterday.  Witch Cycles did a good job on rebuilding it with the rod kit i gave them.  Just waiting on the cases... should be here soon.
Ordered the new rims as well form Dave Langston at The Moto Shop.  Gold Excel Tagasako. 

[Woody]

top class restos there Alex, I'm luvin the brake stay rod. Did you fabricate it yourself?
cheers

[80-85 husky]

a few degrees wont matter eh. she'll be fime