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YZ tranny not working after rebuild - Help me before I turn to alcoholism

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I'll take all of those....

tl;dr - after rebuild its incredibly hard to shift and/or find gears, can get it into first, sometimes second if I'm lucky, that's it. Hard to find neutral from first, and hard to find first from neutral. Thinking external shift mechanism. Thoughts?

:busted::banghead::busted::banghead::bonk:

- Bought 2000 yz125 earlier this year, appeared to have minimal maintenance done on it

- Took it out and 2nd gear didn't work, shifting and other gears were fine

- Tore the whole engine down, replaced

Sixth gear wheel (has the dogs that engage second gear), and

The shift fork that rides in it

(both showed significant wear)

- Also replaced

All bearings

All gaskets and oils seals

Clutch basket

New top end

- When putting it back together, I'm very confident that the transmission and shift cam/forks where installed correctly. They spun fine in the case, and once the cases were back together I could put a socket and ratchet to star detent or back of the shift cam (whatever its called) and could shift through the gears

- Once I installed the rest of the external shift mechanism (arm, shift pawl, etc) I couldnt shift at all.

- Once all back together I note the shift lever is very hard to move and doesnt seem to be finding gears at all. Post on here and decided it will probably be fine if the engine is running.

Put it all back together (whole rebuild took 3 months -thats a seperate issue), she fired up second kick and ran great, I was over the moon. First heat cycle done no issues :bonk::p

Second heat cycle - accidentally managed to put the bike in gear while it was sitting there. Massive bang in the trans. I cut the engine. :lol:;)

Take her out today - something very very wrong with shifting.

- hard to find first from nuetral, however first seems to run fine.

- Almost impossible to get second, pull the shift lever up and it doesnt go all the way up or go into gear sometimes. Sometimes it half shifts and you can hear the gear grinding something but nothing is engaged.

- Cant find third.

- Down-shifting 2 to 1 sometimes I have to shift the lever down like 3 times before it finds first

- Hard to find nuetral from first.

Thinking external shift mechanism. Would a whole kit from a parted out bike on ebay be ok?

Really dont want to split the cases again considering it was such a drama the first time.

help-wanted.jpg

Thoughts?

spent more time fixing this bike than riding it....

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Sorry to hear that. But with that bang you heard something sprang out or in or worse something broke. As for the external shifter, that shaft might be bent. Did it go through its channel easily or under force?

Well at the time of the 'bang' the shift shaft was already installed, but before that when I installed it the thing went in like a hot knife through butter.

I guess a good question is - when I look at the external shifter bits (ie shift parts on clutch side) how can I tell if anything is worn or damaged and needs replacing?

When I had it apart it all looked fine, the springs were all good, everything seemed to fit fine, so unless now when I tear into it again and something is very obviously wrong, how can I tell?

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Normally you are able to see if something is wrong when looking on those parts.

A slightly bent shaft can make shifting harder, it is the only part IMO which could from those outside parts. Can you still shift when using the wrench, I mean through the entire set of gears. It helps when in gear and turning the rear wheel.

The bang was most likely something in the gearbox, I fear that pulling the engine is something you will have to go through again.

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yea last time when assembling I'm fairly certain i could get through all gears.

I'm thinking of picking up this:

http://www.ebay.com/itm/YZ125-YAMAHA-2000-YZ-125-00-SHIFT-CAM-ASY-/270223034786?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item3eea8c49a2#ht_2528wt_1064

It could save me another case split.

Anyone have much luck with buying parted out stuff on ebay? The seller looks legit.

I will split again if needed, done it once so second time round I reckon I'll get it done a lot quicker. Just really wanna get this beast out and ride it! Wrenching is fun.... to a point...

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Although I cannot give an exact answer to your problem I will add from rebuild experience of two motors that, if you could not work the gears smoothly after tightening the cases, something was binding. I did the same thing when assembling my 2001 YZ125. I could not shift after mating the cases the first time, I seperated them again, re-aligned everything and it shifted smoothly thru all gears. The trans has been working fine since rebuild.

Unfortunately, I believe you need to split the cases to explore the problem. Or at a minimum, remover the right cover and make sure the pawl pins are still seated.

Now, if I can't get my plug fowling problem fixed I will be joining you nightly at the pub!

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There is a motorcycle wrecker near me who has the external shift mechanism so I'm gonna go pick it up tomorrow and chuck it in.

I'm hoping that will do the trick, but I'm not holding my breath.

If I have to split again, I think I'm just gonna replace all 3 shift forks for good measure.

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Just wanted to let everyone know it was the external shift mechanism (ie the shift parts on the clutch side)

The shift shaft is fine and I didn't replace it, I think my shift pawl little square arms were worn out, or something like that. Either replaced the lot and it works great now :busted:

Now to chase my jetting issues....

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