Yz 125 trail/ enduro

my 03 has never seen a track. nothing but mountains with tight twisty trails and many obstacles. all i did was gear the thing down on the counter and up on the rear.

from there i added a kickstand. one of the best $100 ever spent. no more falling over on the triangle stand or tree searching.

another cheap(free) mod i did was to cut hand holds through the plastics surrounding the air box. very similar to what the free stylers do to enable superman style tricks. none of that for me(intentionally), but it sure makes it easier to move the bike around when needed. saves the fenders and such. i have duplicated this mod on several.

Did gearing it down help low end torque? That's what my idea is with flywheel weight. Btw, what brand oil are you running and at what ratio?
 

my 03 has never seen a track. nothing but mountains with tight twisty trails and many obstacles. all i did was gear the thing down on the counter and up on the rear.

from there i added a kickstand. one of the best $100 ever spent. no more falling over on the triangle stand or tree searching.

another cheap(free) mod i did was to cut hand holds through the plastics surrounding the air box. very similar to what the free stylers do to enable superman style tricks. none of that for me(intentionally), but it sure makes it easier to move the bike around when needed. saves the fenders and such. i have duplicated this mod on several.

Yeah it's kind of a pain to lift the rear up on a stand on them. I usually grab the subframe to pick it up, I've also tried the swingarm but I only recommend that when the bike is clean (fuel from the carb lines tends to get on the underside of the swingarm which dust and dirt sticks to).
 
Well, the mods have been out on hold. Apparently the previous owners thought that greasing the rear linkage was optional...... So along with the top end I'm doing( for comfort) I also have to do the swing arm bearings and seals, and 2 of the bearings and seals in the linkage. Not a big deal, but not where I would have preferred to put the money.

Does anyone have any experience with swing arm and linkage kits from all balls or other after market companies? There are so many little parts I think I may just save the trouble and buy a kit. I'll price out oem parts too, if they aren't crazy expensive I may just go that route.
 
Yamaha should have a kit available. When i changed mine on my wr thats what i went with. I am using allballs on the steering stem though without issues. The only bad experience ive ever had with allballs was with their fork seals. If you have to change them go with oem kyb seals. I get all my oem parts through cheapcycleparts.com
 
Yamaha should have a kit available. When i changed mine on my wr thats what i went with. I am using allballs on the steering stem though without issues. The only bad experience ive ever had with allballs was with their fork seals. If you have to change them go with oem kyb seals. I get all my oem parts through cheapcycleparts.com

How much was the kit through Yamaha? I rather go oem seeing as how these bearings have been in there for all 10 years. If it's not too extreme I'll go that route.
 
$150 i think it was after tax and shipping but its a different kit for your bike. Should look like this though.Screenshot_2015-04-17-12-12-06.jpg
 
Ended up going with a pivot works kit. Got all my parts BUT the upper rod bearing.... Hate when this happens. Also noticed I have a power valve stuck open so I have to deal with that too.

I was going to recommend them to. They have lifetime warranty on alot of their kits. When the snow goes im gona strip my bike down to replace timing chain and clean carb. Pretty slick deal how they designed the subframe to swing up straight to get easy access at carb.
 
I have found all balls kits to be good but they never put enough lube in their sealed bearings, so I always add grease on any I use. did my wr at 10000km for the rear swing arm and have had no problems with it in 6000km.
 
Opened up a can of worms..... Broken power valve(300$) and now this.....ImageUploadedByTapatalk1430485998.799764.jpg bridge on the exhaust port is cracked, not all the way through but it still is. F¥ck me eh? This motor has never been apart and probably has been running like this for most of its life and hasn't even left a mark on the piston or ring. I know a lot of motors still running with a cracked bridge like this and has never caused a problem. It's common on small bore cyls because it's so thin.

Now I have 2 options:
-1 replace it now for $400
OR
-2 put a new piston and ring in, run it and look for a good used in the mean time.

Option 2 goes against every thing I stand for but I'm not about to dump more money into this bike at this point in time. AND LOOK AT IT THIS WAY, replace it now 400$: put a new piston and ring in and run it till she blows(if ever... Seen a lot of motors o forever like this) and then look for a new cyl plus an 80$ piston, not much loss there.
 
Can it be resleaved?

Nope:(. I called a well known engine builder in my area who does sleds and bikes (bondi motors) and asked them about it, they said that although not ideal, it will be fine. They have seen tons of guy fun with it broke and if it was never causing a problem, probably never will. I'll take the risk.
 
A friend of mine has a 99 yz125 with the same problem. Had the crack fixed and cylinder re-plated, it ended up cracking again. He was told that you could weld up that bridge to make it a little wider so it was less likely to crack. He didn't want to spend anymore money on it so he has been running it cracked and it's been holding up just fine.
 
A friend of mine has a 99 yz125 with the same problem. Had the crack fixed and cylinder re-plated, it ended up cracking again. He was told that you could weld up that bridge to make it a little wider so it was less likely to crack. He didn't want to spend anymore money on it so he has been running it cracked and it's been holding up just fine.

Yeah, I will just keep my eyes open for a good used one. That's good to know that it's been running still. Just waiting on a new power valve my least favourite word.....BACK ORDERED!
 
They even tell you how long it was gona be backordered for? put some new rubber on my bike today and cleaned carb.1431293608728.jpg
 
2-3 weeks. it will be almost 3 this week, im going to call. maybe i can get it rushed or something. if not, im putting the old valve back in for this weekend. ITS THE MAY 24 LONG WEEKEND!
 
2-3 weeks. it will be almost 3 this week, im going to call. maybe i can get it rushed or something. if not, im putting the old valve back in for this weekend. ITS THE MAY 24 LONG WEEKEND!

On 2 seperate occasions i needes a part for my sled for a planned trips so id pay extra and get 1-2 day shipping. One time the part was backordered 2 weeks. The other it took 3 days just for them to ship it. Havent been to dealer since. Be sure to bring your gopro when your out for a rip.
 
oh for sure! it becomes quite the motor storm on long weekends in my neck of the woods. there usually are a few events by local bike clubs that can make for some fun too
 


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