Yz 125 Issues

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1/24/2011 2:01 PM

Well a while back we traded our 03 rm 250 for an 03 yz 125 (and cash) Took it out and rode it ran and rode great then went to the track one day and on the face of a jump it acted like it was in neutral couldn't shift out of it or anything so we took it home split the cases transmission was fine so we figured it was the clutch replaced pretty much everything in the clutch and now it just slips what could be the problem?

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WFO #229

1/24/2011 2:08 PM

I heard they have an issue with the shift return spring or something like that, not a hard fix.

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1/24/2011 2:08 PM

There is a shifting fork in their that is known for braking, hasn't happened on mine, but I have heard of it happening to others.

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Epstein Barr is a form of the Herpes Virus.

1/24/2011 2:08 PM
Edited Date/Time: 1/24/2011 2:09 PM

I know the 05' and 06 motors had weak bearings for the shift stopper and the fix was to update to the 2007 updated part. Not sure if the pre-05 motors have this issue too, but its very possible.



Just gotta pull the side cover off. No case splitting required, so should be easy to diagnose if this is the issue



http://www.thumpertalk.com/...hlight=yz125+stopper

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1/24/2011 3:19 PM
Edited Date/Time: 1/24/2011 3:20 PM

Would that cause it to slip? Would the 07 part work? Thanks alot guys!!!

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WFO #229

1/24/2011 3:22 PM

Off topic, but I'm fully surprised to find honest answers to your question. I expected nothing but sarcasm lol

Sorry I don't have anything more to contribute than that..

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Osama Bin Mixin - Head of the 2-stroke Taliban

1/24/2011 3:29 PM

MX_Andrew83 wrote:

There is a shifting fork in their that is known for braking, hasn't happened on mine, but I have heard of it happening to ...more

Yes, both my 05 and 06 yz125's had a bearing type shift stop, make sure yours is a solid wheel type and replace if it has the bearings with an 07 part. I've seen the bearings ground down to almost nothing at all. Here is good P/N 1c3-18140-10

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1/24/2011 3:31 PM

JW381 wrote:

Off topic, but I'm fully surprised to find honest answers to your question. I expected nothing but sarcasm lol

Sorry I don't ...more

I think one of the things you were looking for was.......... All that and only one period at the end! Longest sentence ever! Sorry wink

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1/24/2011 3:31 PM

Definitely a common problem. I had 2 of those bikes and was constantly dealing with it.

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@dannystu

1/24/2011 3:38 PM

Ds164 wrote:

Definitely a common problem. I had 2 of those bikes and was constantly dealing with it.

I thought 4 strokes were the unreliable bikes?

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4 strokes started this sport!

1/24/2011 3:49 PM

Ds164 wrote:

Definitely a common problem. I had 2 of those bikes and was constantly dealing with it.

MX7MX wrote:

I thought 4 strokes were the unreliable bikes?

It's an 03. How many 03 4 strokes do you know that still even run?

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1/24/2011 3:56 PM

So that causes it to slip?

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WFO #229

1/24/2011 4:10 PM

That is for the transmission this is a slipping clutch problem and the parts are not the same from the years how could that do it?

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WFO #229

1/24/2011 4:29 PM

What kind of clutch did you put in? Have you ever put plates in before?

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1/24/2011 4:32 PM

You do have some play in the clutch lever right? May sound dumb but I have seen people do this before after putting a clutch in.

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1/24/2011 4:35 PM

Trent179 wrote:

You do have some play in the clutch lever right? May sound dumb but I have seen people do this before after putting a clutch ...more

Yes its really a mystery to us why its like this

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WFO #229

1/24/2011 5:13 PM

and oem plates thats the only way to go

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WFO #229

1/24/2011 5:43 PM

We had an 03 and a 05 and they were the most reliable bikes we ever ran.......

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Don't Drink the Kool Aid..................

1/24/2011 5:51 PM

We cant get the clutch figured out otherwise its awesome

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WFO #229

1/24/2011 7:11 PM

I could go through a 15 min. write up on the problem but the best thing to do is just add another fiber disc to what you have now. One of the old ones will work fine. If this is the problem it will get you buy for a few months. Save your money and buy a new basket and pressure plate down the road and you should be ok .

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1/24/2011 10:03 PM

Give us the writeup man we the basket looks fine?

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WFO #229

1/24/2011 10:08 PM

nadeauracing229 wrote:

We cant get the clutch figured out otherwise its awesome

Did you replace the pressure plate and the clutch hub.
And if so was it the right year. It sounds like they are not collapsing tight on to the plates.
Like the pressure plate is worn out.

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1/24/2011 10:12 PM

nadeauracing229 wrote:

We cant get the clutch figured out otherwise its awesome

toolie wrote:

Did you replace the pressure plate and the clutch hub.
And if so was it the right year. It sounds like they are not collapsing ...more

I guess we will try that how can a pressure plate even go bad? The new one we changed on our last kx looked the same as the old one and made no difference

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WFO #229

1/24/2011 10:20 PM

nadeauracing229 wrote:

We cant get the clutch figured out otherwise its awesome

toolie wrote:

Did you replace the pressure plate and the clutch hub.
And if so was it the right year. It sounds like they are not collapsing ...more

nadeauracing229 wrote:

I guess we will try that how can a pressure plate even go bad? The new one we changed on our last kx looked the same as the ...more

They do wear out if the outer clutch plate picks up some debris and it starts eating up the pressure plate same with the hub, Usually it will be discolored or grooved.
And do change the shift stop roller the other people are talking about , I have repaired two my self. P/N 1c3-18140-10

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1/24/2011 10:21 PM

Ds164 wrote:

Definitely a common problem. I had 2 of those bikes and was constantly dealing with it.

MX7MX wrote:

I thought 4 strokes were the unreliable bikes?

SlowOldGuy wrote:

It's an 03. How many 03 4 strokes do you know that still even run?

LMFAO smile

You do have a point there smile

However my 03 TTr 125 is still running but very tired and not worth rebuilding. Typical four stroke predicament.

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Patrick Trowbridge

1/24/2011 10:25 PM

Babba Boey on here had his bearing in the shift fork fall apart and down into the tranny and nuke the entire thing, Yamaha forgot to put out a bulletin on this very simple fix. Don't hesitate if that is what the problem is. BTW is your clutch basket in decent shape?

Sometimes if you put a little sawdust in there it will tighten things up. smile

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Patrick Trowbridge

1/24/2011 10:29 PM

Will the 07 part work in the 03?

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WFO #229

1/24/2011 10:34 PM
Edited Date/Time: 1/24/2011 10:41 PM

nadeauracing229 wrote:

Will the 07 part work in the 03?

not sure

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1/24/2011 10:39 PM

On some YZ125 the clutch pressure plate has to be "indexed". That means, the pressure plate aligns with all 5 clutch spring towers, but only fits all the way down on ONE OF THEM. Take the springs out and keep rotating the pressure plate until it fits all the way down on the first fiber plate. If you have it on the correct one, it will make all the difference. Also, make sure to measure the thickness of the pressure plate, if it's worn, you will install a new clutch and it will still slip.

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1/24/2011 10:41 PM

nadeauracing229 wrote:

Will the 07 part work in the 03?

Scratch that I just looked it up they look totally different. Sorry.

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