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engine problem... plz help

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hey.

so to start off I bought a new/used 2005 Yamaha yz125 about 3 weeks ago. Guy told me the clutch needed adjustment and it ran good and everything. thing I noticed was that the clutch seemed to be worn out. he told me it needs to be adjusted. which I didn't really believe. So I get it and been riding like everyday at motocross track for the past couples weeks with no problems at all. just yesterday something in my inner engine grinded. I don't think its piston. I was going down a hill in 3 gear and I went around a berm and halfway through it I dropped down to 2nd. as soon as that happened something inside motor grinded, gears or something in tranny im assuming. I continued to riding and it didn't bog out or stall yet. maybe 8ft later I was going up a step up and bike stalled. picked it up and I tried to kick it over but it was seized. and the clutch was gone. like there's all play in it like the cable snapped but nothing was broken from what I seen at that time. it wouldn't go into gear or anything so I had to break chain to move it. I brought it home and took off clutch. under the pressure plate was that centre bolt that drops in. I can post pics of it later or if someone asks. but the bolt that just drops in had one huge gash all the way from top to bottom. bolt isn't very big. went I had all the plates out and pushed the kicker over it sounded like something a little further down was rubbing/gridding. if anyone has had this issue or has an idea of what happened lemme know. Thanks   

 

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Whew, what a mess, I feel your pain.  

 

Take the pipe off and look inside the cylinder and look for nasty scratches.

 

Take the clutch all apart and see if the basket will spin freely.  Start eliminating variables, one at a time.  Hang in there, these guys will help you get it going again.

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ill try haha. I wanna get this fixed before September 5 cause I wanna race so bad. but yeah. hopefully ill get soe tips on here. Thanks!

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One thing you could check is the clutch actuator on the ignition side. On these bikes it has a flat that the pushrod sits in. As the clutch wears it creates a misalignment between the two parts and the hand lever will go completeley loose and have a ton of freeplay. I had it happen on our 11 yz125. Make sure your inner hub is OK as it can literally become bent and not run true.

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The part I'm point at is seized. It's not recoiling back out into position. Basically it's stuck in the disengaged position. So something in my tranny is causing everything including gears to be seized. The was on the shifting side.

1439611068107.jpg

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Take off the clutch cover and the clutch plates then pull out the push rod , just watch as the 125's normally have a ball bearing on the end of the push rod.

 

Once the rod is out you can remove the flywheel and the cable from the clutch arm you pointing at in the pic , the clutch arm can then be pulled out.

 

It is probably worn on the end which has caused the push rod and arm to jam .  

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Im pretty sure the 2005 yz 125 had a problem in the tranny from stock and were renown for destroying the bottom end the problem was fixed in 06. But im not sure what part it was. This may be your problem not entirely sure but i will look further into it for u.

Hope u find your problem! :)

EDIT:

The problem was the shift stopper and it was not fixed in 06 but was in 07

Here is a link on how to replace it and more details i hope it helps

http://www.thumpertalk.com/topic/512858-replace-your-shift-stopper/

Edited by Max.J331

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I think you found your problem. Did the tiny ball bearing that fits between the pushrod and pressure plate disappear? That could have caused the big gouge you describe.If you can get the pushrod out its an easy job to replace the clutch arm and pushrod. I'll bet that if you measure your plates and fibers you will find that they are at the service limit. Even if the springs are good and within the free length spec the wear from the clutch has caused them to not hold enough pressure. As the whole clutch assy wears the clearance created forces that pushrod further towards the ignition side of the engine and the pressure plate also moves that way with wear which creates a situation where the springs installed height is longer,hence the lack of spring tension regardless of spring condition. Is your clutch ez adjust at the limit of its usable range? That's another indicator.

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Thanks guys for the help and ideas. I think I'm bringing it to one of my buddies and he's gonna take it apart and fix it. I'll let you all know what the issue was later on. If I end up doing it I'll keep posting pics and what's happening

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Its the cover thats behind your kick start youll have to remove your water pump its a cover that goes onto your crank case. So you have a clutch cover then the clutch cover bolts onto the the side cover. Remove this and you should be able to remove your basket

EDIT:

Actually you shouldnt need to remove the side it should come off easily just turn it a bit then if it doesnt take off your side cover and have a better look

Edited by Max.J331

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That basket is cactus. I bet you would've had heaps of clutch drag and it would've been a bit of a pig to start in gear.

The washer between the inner and outter baskets is also splined and needs to be lined up before you can pull it, and the basket off. Can't really tell if it's still there or if you've removed it.

Edited by EYY

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I agree eyy. Clutch basket is really notched.It should come off easily. If not the inner bearing is toast or its in contention with the drive gear. Good luck

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That basket is cactus. I bet you would've had heaps of clutch drag and it would've been a bit of a pig to start in gear.

The washer between the inner and outter baskets is also splined and needs to be lined up before you can pull it, and the basket off. Can't really tell if it's still there or if you've removed it.

yeah, I could never, like not once get the biked started in gear. All it would do it do is kinda jump forward without engine fire.

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That basket is cactus. I bet you would've had heaps of clutch drag and it would've been a bit of a pig to start in gear.

The washer between the inner and outter baskets is also splined and needs to be lined up before you can pull it, and the basket off. Can't really tell if it's still there or if you've removed it.

is this the wash you're talking about?

1439749410142.jpg

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That basket is cactus. I bet you would've had heaps of clutch drag and it would've been a bit of a pig to start in gear.

The washer between the inner and outter baskets is also splined and needs to be lined up before you can pull it, and the basket off. Can't really tell if it's still there or if you've removed it.

I got it out but it's looking like something not right in here. Bearings just fell out. I'll post some pics

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Its the cover thats behind your kick start youll have to remove your water pump its a cover that goes onto your crank case. So you have a clutch cover then the clutch cover bolts onto the the side cover. Remove this and you should be able to remove your basket

EDIT:

Actually you shouldnt need to remove the side it should come off easily just turn it a bit then if it doesnt take off your side cover and have a better look

1439750080312.jpg

1439750128194.jpg

1439750162402.jpg

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Your kickstart gear looks pretty bad. How does the big gear on the basket look? I'd get a new basket. I just put a wiseco on a 13 yz 250 and it came with the kickstart gear new and already installed.Not sure if the part for the 125 comes like that. If the basket is that beat up how do the splines on the inner hub look? Not good I bet. With all that are you able to spin that shaft and notice any crunchy sound coming the trans? You should be able to spin the shaft and run it up through the gears. If that seems OK your probably good once you she'll our some cash for clutch parts.

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