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06 YZ 125 Project

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Hey folks,

I'm delighted to be back in the YZ 2 stroke forum after a bit of an absence. I used to own a 03 YZ 125 which always regret selling. I currently own a 2011 yz 250f and owned a 03 rm 125 until recently when I sold it to a friend. Only a few weeks later I got the 2 stroke itch and began looking for a 06+ YZ 125, after being blown away by the SSS suspension on the 250f. A few came and went that I missed out on but finally one popped up. Advertised as a 2007 yz 125 (vin checks as a 06) priced at  2500 Euro. The usual BS advertised was on the ad "good tires only one ride, chain and sprockets good etc " Arrived down and found the chain and sprockets absolutely shot, tires were worn, Leaky fork seals(looked like new oil?) rear fender broken few bits and pieces. Talked him down to 2200 euro and was happy enough with that. Picked it up on friday on my way home from college and started ripping it apart. And that's where things go down hill:lame: 

Found the air filter in a shocking state (see pics) which caused a major groan.... still at least its a 2 stroke. From looking in the exhaust and intake ports I could still see crosshatching very clearly, unfortunately I didn't have time to rip the cylinder off yet. Counter shaft seal appears to be weeping so that will get replaced, also isn't there an issue with 06 shift stopper or something? It does have unbreakable levers which is one of the few plus's

All of the bearings will be inspected and replaced if necessary, new top end most likely, new bars, grips, tires, fork seals, chain and sprockets, air filter, restyle plastics more than likely and whatever else I uncover :ride:

Keep in mind this will be a slow build as I'm in college 5 days a week.

Now some pics

 

 

yz 1.jpg

yz 4.jpg

yz 3.jpg

yz 2.jpg

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Well, I am going to say I guess it was a good price, and welcome back to YZ.

BUT. Always bring some tools with you to look at things. If you can see all the abuse, the idiot should have gone lower. Hope you didn't suck to much of that filter material in if you started it.

RMATV=OEM main seal, ProX gasket and seal set (doesnt come with the mains), right size Vertex or OEM piston, and whatever other bits it may need. Put a list together, I'm sure they ship to you unless found on your island. 

:thumbsup:

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Yes the original '06 shift stopper has a design 'weakness'

(a bearing that can fail and send bits thru the gearbox rather than a solid roller wheel)

if not already done, it should be replaced with the improved version.

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Cheers guys, Yeah I regret not asking to remove the seat to see the filter. Oh well live and learn.

Arrived home from college today to find a nice stack of boxes.

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Apologies for the crappy pictures but in these was: 2x MX52 rears and 1x MX 52 front, (one rear for the 125 and one for the 250f), new rear fender for the 125 as a birthday present from my brother,  new xring chain and sprockets, air filters, fork cap wrench (forgot to order the compression wrench:smashpc:), a bead buddy and spare tube, Pro-x fork seals and dust seals- however I need to order another set as both the 125 and 250 are leaking,tie down straps, and finally just a Mikata drill and impact set for my birthday.

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Finally I took the cylinder and head off the bike. Found a badly worn piston with a lot of blow by and some scratches. I don't think the cylinder has ever been taken off as all the nuts look untouched. The cylinder looks to be in good shape for the most part, a lot of crosshatching visible, however the ports look like they could be a little worn so need to get a second opinion. 

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Made a bit more progress today:  Stripped the rest of the bike down, loosed the fork caps and removed the forks, removed ruined steering bearings, removed swing arm etc basically down to the bare frame. Also removed the clutch and engine cover to gain access to the shift shaft and shift stopper. Going to replace that with the updated part.

I also attempted to remove the fork cap from the YZF forks but I couldn't get it undone, using the proper tool and all. Someone had the cap off previous and slightly damaged it and apparently over tightened it in the process:banghead::banghead: So does anyone have any suggestions on how to remove the cap?

I absolutely LOVE that little Makita Impact in the last photo, it's absolutely perfect for the bike makes life so much easier and quicker

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SKQSg_LaLScnSeUZdmA47IHn3mwas85uFXRyMZ_X

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You should also plan on servicing the forks & shock, (oil, bushings, seals, nitrogen).

In some cases, the '06+ 'SSS' KYB forks can develop cracks in the ISC free pistons.

If yours aren't damaged, preventatively doing the 'free piston mod' (drilling a few holes) can prevent it in the future.

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1 hour ago, mlatour said:

You should also plan on servicing the forks & shock, (oil, bushings, seals, nitrogen).

In some cases, the '06+ 'SSS' KYB forks can develop cracks in the ISC free pistons.

If yours aren't damaged, preventatively doing the 'free piston mod' (drilling a few holes) can prevent it in the future.

I plan on doing all of these on both bikes, just as long as I can get the caps off the YZF forks... going to take them to a suspension shop during the week to see if they have any ideas

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Just ordered the final parts I hope... piston kit, gaskets, rear wheel bearings, steering bearings, fork oil, fork seals, shift stopper, sprocket bolts, exhaust packing and I think that's everything. Restyled plastics will have to wait a while as this is costing more than I expected:p

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Just ordered the final parts I hope... piston kit, gaskets, rear wheel bearings, steering bearings, fork oil, fork seals, shift stopper, sprocket bolts, exhaust packing and I think that's everything. Restyled plastics will have to wait a while as this is costing more than I expected:p

 

steering bearing.jpg

Edited by owainyz03

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Annoyingly the photos has disappeared so I'll re upload most of them. Shift stopper arrived yesterday, look at the difference:jawdrop: Caught it just in time!

 

Parts.jpg

Piston.jpg

Shift stopper.jpg

Cylinder.jpg

Frame.jpg

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Your old shift stopper is missing parts, hopefully they aren't floating around in the gearbox.

This is what the original 'problematic' design looks like, when it fails it sends it's tiny bearings loose to create havoc.

DSC_1727.JPG

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Oh no :thumbsdn: I did find some metal alright, hopefully it's all gone.... Got some more parts in today, fork seals, steering and rear wheel bearings, packing, piston kit, gaskets and fork oil.

Annoying found the circlip in the rear wheel bearings to be missing so I need to get a new one, anyone know if it's a special size or should I get able to find one?

Installed the shift stopper, piston and got the engine all buttoned up. I sure hope I don't run into any issues....

Had some problems installing the steering races so decided to call it a day. 

 

engine.jpg

metal.jpg

parts 2.jpg

piston 2.jpg

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Some more updates, got the steering bearings in, cleaned and greased all the linkage, and started assembly. Repacked the exhaust although it wasn't too bad really, bit of a pain in the ass to line the core up on reassembly. Got the engine, subframe, rear plastics and radiators mounted. Not quite sure of the routing of the electrics around the top rad hose so if anyone could snap a pic that would be helpful, and the connection from the engine to the loom, by the bottom hose.  Also removed a spinning insert from the tank and must glue that back in

I'm still waiting on a fork compression tool to do the fork seals along with the countershaft seal kit:lame:Need to change the tires, order a new gear lever as mine is almost stripped, a rear circlip for the wheel bearings

 

assembly.jpg

roller bearings.jpg

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owain, did you get the new-design upper steering bearing? It has a built-in seal, whereas the original didn't. It's mentioned in this thread...

If you got the older bearing (no big deal), use the 4-stroke top seal; it's seals better, as mentioned here...

 

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1 hour ago, CaptDan said:

owain, did you get the new-design upper steering bearing? It has a built-in seal, whereas the original didn't. It's mentioned in this thread...

If you got the older bearing (no big deal), use the 4-stroke top seal; it's seals better, as mentioned here...

 

Damn no I didn't the Pro-X kit I got was just the run of the mill stuff. Actually something I found interesting was the lowering bearing in the kit was an All Balls bearing... :smashpc: And there was two bottom seals included strangely....

Thanks for that info :thumbsup:

Just ordered what I hope will be the last of what I need.... seems I say that alot:( : Gear lever, got a 3 pack of grips, engine oil, air filter oil, spark plug, fuel hose and a bolt kit for the plastics, oh and the circlip for the rear bearings..... I hope to be riding by next weekend but who knows... hopefully one of the bikes will be going

Edited by owainyz03
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Got a few more bits done this morning. Mounted the radiators, tank, and few bits of the plastics. I have a bolt kit on the way so some of the stuff is only temporary. I wasn't sure about this wiring, maybe someone can shed some light.

Apologies for the crap photos, the messy garage doesn't make for a great backdrop

assembly 2.jpg

wiring.jpg

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some pictures of how the routing of the cables has to be: 

 

the water overflow can you see on the last picture, its comming together with the powervalve hose on the left side

20161125_150826.jpg

20161125_150852.jpg

20161212_160707.jpg

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