YZ125K Rebuild

[Richo52]

Yes that bike was awesome Rosco ,you let me ride it at Beverley ,it went really well.

[alexbrown64]

Cheers fellas, yes, i think they go well and so light.... i cant be arsed trying to lug a tank around the track any more.
Anyway, finally got the Race Tech suspension back......



Finally i could take it out for a photo shoot.  The bike is going to need lots of small adjustments.  It needs to be run in, tuned up, suspension set and a host of other bits and pieces but its a runner now.....







Project completed...
Cheers,
Alex

[smed]

  The forks feel stiff at the moment.  Maybe they need running in, maybe they need adjusting....

Alex,I put a set of race tech emulators in my 43mm Yam forks set up similar to yours with springs to suit my weight,new bushes & seals etc & found they are stiff feeling when bouncing on them in the workshop but near spot on when riding,a test ride will tell , I have found modern forks to behave that way too, those emulators really emulate
The bike looks awesome,Are you putting on number 224?   

[alexbrown64]

Thanks for the feedback Smed.  I will take it bush soon to run it in and bed all the components down.  I think my spring preload may be up around 15mm.  Recommended for this bike is 5mm.  Race Tech says make changes in 2.5mm increments.  Just wondering if that can make it feel a lot stiffer when just sitting on it.  The new back shock feels perfect.
As for the Lechien 224 numbers...  i may put some on when i get the DLS front brake and everything is finished just for a photo shoot. I will be re-registering with the MWA soon so not sure if i can score that number.  I doubt it... to old and slow now.. i think they reserve the 900 numbers for guys like me.
Cheers,
Alex

[Ted]

Very nice job. All it needs now is Ron to sign it. Stay tuned 

[80-85 husky]

Another work of art

[mainline]

Very schmick mate, great attention to detail

[Rossvickicampbell]

Alex - if you sign up for Classic MX WA whole different numbering system now - certainly not 900 competitors there yet 

[FourstrokeForever]

Great work Alex. You sure do know how to bring a bike back to life. Well done

[r4brightred]

Pure eye candy! Nice work.

[smed]

  I think my spring preload may be up around 15mm.  Recommended for this bike is 5mm.  Race Tech says make changes in 2.5mm increments.  Just wondering if that can make it feel a lot stiffer when just sitting on it.

Yep, that's what i'm thinking  , I used what  Race Tech called there  triple rate spring kit  to suit my weight which I thought meant just that, a progressive spring but when I opened the box to my surprise I found 2 long springs & 4 short springs which were about 50mm long, On reading the instructions it all became clear,The long spring alone is the stiffest rate 0.46, the long spring + 1 short spring is 0.43 & the long spring + 2 short springs is 0.40, I needed the 0.43 set up according to them so that's what I fitted, The kit also came with spacer material which seems to be  thick walled PVC, so you just calculate how long they need to be & cut to suit, I will use this type of kit again if I need new springs for another of my bikes because of the tunability  

 

[alexbrown64]

Thanks for the comments fellas. 

Its been flat out but worth it, as i hope to race this one in the future and then keep it for the boy. 
Anyway Smed, and anyone else that has been playing around with the emulators.  I was lucky in that i found a bloke in the US that used to race this model and he gave me the contact details for Matt Wiley at Race Tech in the US who in turn gave me all the settings to use.  Smed, i also have the .43kg springs in. However, initial feel on the bike gave me the impression the rear was great but the front was really stiff and there was no sag.  Forks apart again and the first thing i did was take the emulators apart and drill two more holes in the bleed valve.  Mine only had the standard two, but Race Tech recommends four holes in the bleed plate.  This softens up the initial stroke.  Then i reset the preload. I had nearly 15mm which is way too much.  I reset this to 2.5mm.  Got it all together and what a difference.  If i sit centrally up near the tank and bounce up and down, the bike goes up and down evenly and nice and smooth.  I now have some sag in the front and everything feels balanced.

I wheeled it out the shed and fired it up.  Took it for a ride around the garden and all good.  Brakes, clutch, gears, everything smooth.  Bike runs well but a little oily and a lot of splooge coming out.   Its early days though and i will need to adjust the air screw and run it in.

Cheers,
Alex

[Lozza]

I like to use acorn/domed nuts on head studs with copper washers underneath. Nice job. Have you burned/shredded all the  receipts so the Mrs happen across them

[alexbrown64]

Thanks for the heads up Lozza.  I stopped in at Masters and got some 8mm SS domed nuts.  Copper washers are harder to get.  Want 8mm x 16mm x 2mm.  Masters didnt have them, or Repco or the local bike shop.  Ordered a pack of 20 for 7 bucks delivered, correct size on Ebay.  Not sure what i would do without Ebay these days.  I have also ordered some YZ80J exhaust gaskets which are a much thicker material and recommended for the bike in the old magazines.  I will do all these mods together as i have to take the pipe off to cut down one of the cylinder head studs which is a bit long.
I also got an email back from Jon Easton who runs the Jon Easton Manufacturing Co. (JEMCO), who hand made the cone pipe.  Gave the bike the thumbs up.
As for the receipts, i would rather burn and shred the missus first   
Edit: The bit about the missus is a joke... please dont try this at home 

[80-85 husky]

I would seriously modify that last post Alex