How to move shift assembly to align with shift stopper

How do I make this rotate down where it it should be on my yz125? It will move some but not where it should be?




Try turning the countershaft with some pressure on the shift drum.  Should click through.

What do you mean by countershaft, sorry I'm pretty new to working on motorcycles

Never mind. It works thanks a lot!

Power from the cylinder/piston turns the crank.  Crank's got the flywheel/stator on one end, primary gear on the other.

Primary gear engages the clutch hub, power through the plates, and to the inner hub.

Inner hub turns the transmission shaft.

Gears on the transmission shaft engage with other gears on the countershaft. 

Shift forks move the position of the gears on those two shafts.  The shift forks are moved through slots on the shift drum.

Countershaft pokes through a seal that your countershaft sprocket (small one) is splined onto. 

Through the chain, to the rear (wheel) sprocket. 


The gear stacks on the transmission and countershaft may not line up with everything sitting the way it is.  Turning the countershaft changes the alignment of those gears; putting some pressure on the shift drum will let it 'snap in' when the gears are aligned.


Counterbalance is on the far left, your engine may or may not have one of those.

Big one to the right of that is the crank. 

Clutch goes on the other side of the engine case. 

Transmission (upper) and countershaft (right side).

Hollow aluminum thing is the shift drum.

Shift forks ride on the dowels between the transmission/countershaft and shift drum.



All those pieces out of the engine...


Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By faizakhtar125
      Hey guys I just bought a bike last night. So the seller said the bike will turn on but then die. We didn't try it because it was really late at night and it was raining (seat was wet). But he said if you bump start it, it will turn on and ride. So what do you think the problem is? I just want to make sure it runs... I probably won't be able to bump start it till Saturday (rain)... It's a four stroke, and I know absolutely nothing about them. Thanks.
    • By neonmarine
      Hey guys, 
      I've used this forum as a "guest" for awhile now and I thought I'd share my build now that it's all coming together.  The primary purpose of this project is to help me train for roadracing my 2009 R1 at lower speeds as well as giving me a cheap alternative to racing the big bike. 
      Here's what she looked like when I picked it up from a local shop.  Paid $800 cash for the bike as you see it with 17' rims, FMF pipe, EBC 250mm front rotor and clip on handle bars.

      Fits PERFECT!

      Shake down run at the Herrin Compound last summer:

      As she sits today:

    • By 125 yamaha guy
      i bought my yz125 from a dealer and they said that the clutch was broken so i bought it and it worked fine it would run move and everything and then it started to act up and now only first gear works barely though. when you put it in first it acts like its bogging down but its not and when you go into gears 2-5 it wont move i dont know whats wrong with it im assuming the clutch is slipping or something if you know please leave me a comment 
    • By Randomneewb
      Hey guys, I have a 2003 cr125 I bought a couple weeks ago and I'm having a problem with it. The spark plugs die every about 15 minutes, with hotter plugs it will last about 45 minutes. I herd that if the timing is off it can over heat the plugs and burn out the the resistor. Is there any truth to that? The reason I thinks it's not fouling is because when the plug dies it gives no spark no matter how much you clean it, And it shorts out.