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  1. I am trying to put this 2002 YZ125 back together from a box of parts. Can anyone help identify this missing part? Looks like a good spot for a hose clamp but cannot find in any OEM microfiche. See attached pic Thanks
  2. So my yz125 is having some trouble. I went to the track this weekend and everything was great then when I got home the bike wouldn't start. The next dat I put a new plug and saw that it was flooded so I bump started the bike and it ran fine. A couple hours later I went to start the bike and it was fine so I rode it around the yard. Then after riding for a bit I let it sit, went back a few hours later and had the same problem as before. I bump started it again and noticed that it wasn't idling it would just cut out. My guess is the piston rings are gone but I could easily be wrong. I don't really know the condition on the top end I bought it two months ago and it had been riding fine. I'm getting a compression tester to see if it's the top end but would want to know anybody thought it was something else.
  3. I’m looking for a cheap but decently looking and running YZ85 or 125 in the State college PA area and I’m willing to pay cash my range is 600 - 1200 💵 if you comment please attach a photo and I’m only interested in bikes in the area , thank you
  4. Hi, I have a 99 Yz125, split cases because po ran out of oil and stuck in gear (idle gear seized to shaft) got everything split put in used shaft with idle gear. The shift forks show no sign of wear and shifted fine but shift stopper had very little play in wheel and the shift star where it sits on seems maybe worn but had no other to compare. Rode it and sometimes hits false neutral in 4th-6th sometimes if you don't click up with enough force or right click but the times it does not have a issue it revs great in those gears and does not pop out under a load what so ever just if you half ass click out of a corner for example it hits false neutral and i have to sit there and pop it down and start from second or first. I have a tusk clutch in it, maybe bent shift shaft or worn shift star with worn shift stopper? I replaced almost everything except shift forks, shift shaft, shift stopper and shift star. Thanks for any help
  5. Hey Folks, I recently did a top end on my YZ144 and upon firing it up and breaking it in, there was a small coolant leak from the head gasket. It is a metal/plastic sandwich style Athena gasket as below. I chalked the leak up to me installing and torquing it a few times to check squish. I think it went on/off 3X. I should have used the old one for squish testing, but wasn't thinking. Now I am considering whether to use some Permatex copper spray gasket or something before installing the new one, or just going dry again. Thoughts?
  6. every time i turn on the gas, it flows out of this and i’m not sure what it is or how to fix it
  7. Greetings, Long story short, I discovered my oil drain plug was stripped upon inspection for this upcoming riding season. I have a 2017 Yamaha YZ125 and was wondering what size drill bit I need to buy for my helicoil kit. I ordered this kit here: https://www.amazon.com/gp/product/B0002SRG34/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 which is for a M10x1.25 size, the same size as the OEM drain bolt, which I still plan on using after (new bolt and crush washer of course). Would I purchase a drill bit that is size M10x1.25 as well, or would I have to get a bigger drill bit to fit a helicoil with size M10x1.25 in? Thanks everyone!
  8. I have some Yamaha YZ85 bars but I want to use the triple tree of a Yamaha YZ450. My question is, Do all Yamaha YZ’s from 85 onwards have the same diameter on their forks?
  9. hey guys, just wondering if i did any damage to my bike, i just finished a little job and began trying to kick it over without oil in it, im just wondering if this would have done any damage as it didnt actually turn over. I put oil in it and it seemed to run fine after that. do you rekon this has done any damage?
  10. Sorry if I don't give enough info with my question, I am pretty new to the forums and am learning as I go.. I have an 89 yz that I picked up for 50$ in December that was left outdoors and when I picked it up the bottom end was exposed in the snow.. The top end was blown as the piston had caught the powervalve, sucked the dowel pin into the cylinder which rattled around and destroyed it. I bought the bike to learn about how to build and work on a bike so the process took a while but I was able to replace the bottom end bearings, replaced the crank, new piston, resleeved both to the stock bore and it started up and ran to my surprise. However, having never owned or ridden a 2 stroke, I added extra oil to the fuel mixture to ensure I didn't fry the top end in the first break in which I have learned isn't exactly the best option. Anyway. after about 30 minutes of break in, the cylinder has scoring similar to the older sleeve near the exhaust port as ill show. Is this normal for a break in or is there something else going on?
  11. So, I just finished completely rebuilding a 2000 YZ125. I just finished heat cycles, so today I decided to give it a ride to see how it does. I got off in first gear doing alright and then all of a sudden I was about to shift to second and then it bogged way down beyond the point where you could pull the clutch and save it from dying and it died. I started it again and revved it to see if it would clear anything out and it did somewhat, but when I shifted into second it bogged and died AGAIN. So now I’m getting frustrated because it won’t even let me take off in first gear because it just bogs no matter how much throttle I give it. I don’t know what it is. I’m running motul 800 premix and I run 32:1. Any advice out there on how to fix this?
  12. Why are the teeth bending forward towards the front tire? Aren't they supposed to bend the opposite way towards the back tire? Thanks. Shoot this is the wrong bike. This is my nephew's 150xcw front sprocket. Sorry not a yammi question, but would anybody have any insight on this? Moderators if you want to move it you can sorry.
  13. I have the cylinder completely apart and the right side power valve is stuck...it won’t come out. The left slid right out. I don’t want to damage anything. I sprayed some PB Blaster on it but still stuck (maybe that’s not the best for carbon). Thoughts?
  14. Hey guys, so I ordered a 9 oz flywheel weight for my yz125 and received what looks to be the completely wrong part. It is literally just a weight, no set screws with it or anything. Does anybody know if this will fit my bike?
  15. My clutch is moving mad, so the bike kick starts first kick from cold, but when I put her in 1st,2nd or 3rd from still and let off the clutch it’s like it’s still fully disengaged? And moves slightly but like less than 1%. When the bikes not started and I push it in any other gear than neutral even with the clutch lever held down the back wheel locks up and drags slightly. So here’s the back story: So I bought a yz125 2005, let the person I bought it from ride it to show it’s in working order as didn’t have cash. Turns out he bump starred it. Opened her up and the clutch rod was snapped in two. So ordered a new one, while it was opened ordered an actuating arm, clutch basket, pads, plates and springs - also got a new clutch lever unit and cable too. Everything is installed now and when pulling the clutch it feels brand new, the actuating arm comes up and the plates release as it should only slight issue is how tight the cable is but I don’t think it’s that as the actuating arm is still all the way down, far enough to actually hit the bottom of the clutch cover. Need any advice I can get please, anyone. Thanks
  16. I apologize if this is the wrong place to post. I did a search and I dont believe I have enough posts to put it up on the classified section. If a moderator could do that for me, much appreciated. If not, we can exchange payment info and I will ship to anywhere in the US. Here is a V Force 3 Reed Block with the reeds in good, non worn out or chipped condition. These retail for 125+ dollars, so lets start the negotiations at $70. The gasket is slightly worn, but should work out ok. If not a $5.99 boyesen rad valve gasket from motosport or rmatvmc will work just fine. It was pulled out of a 2002 YZ 125, so its up to you to determine if it will fit in yours. I believe any YZ from 98-new will work, but please do your research first. Here are some pics
  17. Should i replate my oem cylinder or can i get an athena standard bore 54mm(not iversize). If i get athena i can sell my oem cylinder. Is there any benefit athena has over oem?
  18. hi everyone, i recently overfilled my gear oil by roughly 150ml without realising, i rode my bike for quite a while (30 - 60 minutes) before it started groaning and squealing (thought it was breaks) and making weird engine noises, before bogging out and then becoming very hard to start, i rode it back onto the road where i could get picked up from, took it home and drained the oil completly and put the correct amount in aswell as a new spark plug. the bike has not lost compression and seems to be running and revving ok but it still groans a little bit from the engine and it blows way more smoke than usual, i have not rode it yet but just wondering what it could be, what i should and need to do. Any help would be greatly appreciated
  19. So I replaced the Governor Spring , the 3 washer plates and the 2 thrust bearing/washers and the collar on my kids 2005 YZ125 the other day and felt satisfied that I did a good thing on a 15 year old bike... I'm figuring those parts were original, cheap enough, and I put in the YZX spring while I was at it. Then I got bored and started to read all the threads on the Governor Washer/Spring mod for the 250's... I ride a 250. So in there, I read about when re-connecting the linkage that you should not have to lift up on the arm to reconnect and it should just line up and press on. On my 250, when doing top-ends this is what I experience. But on my 125, this has not been the case and I never really thought much about it until last night. On this bike I have to pull up on that arm ever so slightly to get those flat surfaces of the link to line up with the flat surfaces of the shaft. It's not far off from just sliding on with no issue, but I do have to slightly pull up on it. I threw in some picks that show how close it really is to just sliding back on as well as what the p-valves looks like when open and closed. What do you all think? Is that little bit that it's off acceptable? Bike runs really well, no issues whatsoever.
  20. I recently bought a 2014 YZ125 with fairly low hours. What I have done so far is... Rebuilt the carb(stock jetting with needle in std position) New Spark Plug New Twin Air filter Repacked the FMF powercore silencer (stock expansion pipe) Changed the transmission oil I'm pretty happy with how it runs. I think I could drop the needle 1 clip. I'm running Klotz R50 40:1 with 1/3 VP C12 and 2/3 90 Ethanol Free. The problem I'm having is the balance of the bike. The rear end feels bouncy and gets really light any time you touch the front brake. I'm 5ft5in and 145lbs. I checked the static sag and it was at 30mm. My race sag was 84mm. As far as I know, the suspension is stock. My dad who is 175lbs got 108mm of sag. I couldn't find a jetting chart or a sag chart in the owners manual. Only found shock preload. It seems like I could get the sag for him to be within spec (25mm static, 103mm race). My question is what rear spring rate is stock, and which rate should I drop down to? I think the front forks are pretty good. thank Johnathan
  21. Hey guys doing my first full rebuild done crank bearings new crank my question is when putting the cases back together the transmission was spinging good however when i tightened up case bolts the sharft stopped spining its like its really tight i have to put clutch basket on and turn with force to get it to move please help ive split cases over 4 times each time looks fine nothing wrong gears spin smothly its when i put cases back together and tighten engine case bolts down
  22. I have an 03 yz125 and I have a pro x piston in that’s an A size. I’m looking for a B sized pro x and I can’t seem to find/understand the right size. It has been replated with steel already and was still stock. I know B size is 53.961~53.964mm as far as the manual says. Thanks, Kodie
  23. Will a stock 2002 yz125 exhaust pipe fit on my 1999 yz125
  24. Hello! I am currently rebuilding a 1991 YZ 125, photos here: https://photos.app.goo.gl/ZDjkk38BzmM4iQ1L6 I finally got the engine rebuilt and back in the frame. I was lucky enough to score an OEM 91 yz125 exhaust header in VG condition on ebay, but it does not fit my bike!! I couldn't understand why, I wondered if the person I bought it from made a mistake and it wasn't a 91? Well then I noticed that my cylinder head has a number stamped "3SR" I looked that up and apparently that is a 1990 cylinder? 1991 should be "3XJ", my bottom end engine serial number starts with 3XJ so im pretty sure the rest of the bike is a 1991, maybe someone replaced the head with a 1990 at some point in its lifetime? I have no history of the bike, so who knows what happened over the years and the bike was not running when i got it, the previous owner bought it as a project and never had it running. SO I am very concerned if the cylinder is a problem, its such a shame cause I sent it out to Power Seal and had it re coated! My main questions are: 1) Will a 1990 cylinder work with a 1991? 2)Will a 1990 exhaust header fit my setup? 1991 bike w/ a 1990 cylinder. Is the frame different over the years? I know the cylinders changed each year from 90 to 91 Any help would be greatly appreciated! Thanks, Joe
  25. Son is going through his "new to him" 125 and checking everything over and replacing what needs replacing. I see in the manual that the listed fuel level using the fuel level gauge is 9.5-10.5mm above the float chamber mating surface. I seem to remember that most people set the level a little different for typical woods use? Is that correct or am I imagining things? What is the consensus here? Thanks so much.
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