YZ426 - Help needed with removal


10 replies to this topic
  • YZ Yankee

Posted September 06, 2015 - 09:03 AM

#1

I'm running into some issues as I attempt to pull the head off.
1. The bolt in the photo is catching on somehing inside the head. It will not come out. Any suggestions on what might be the problem and solution.



2. The #7 nut, toward the intake side of the cylinder is in accessible. Clearance is about an inch.
You can't get a socket in there. An open end will strip it.
Thought about pulling the entire engine, then pulling the cylinder and head off as one piece. Then I'd have the room to get to it .
Will that work?


Is there really only 2 bolts holding the cylinder to the lower case?
3. Look at photo 3. Is that a gouge made by the valve? That valve clearance measured .17mm. Specs are .10mm to .15mm.
Thanks for your help.

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Edited by YZ Yankee, September 06, 2015 - 09:21 AM.


  • mortimor

Posted September 06, 2015 - 09:35 AM

#2

I hope i can help a little here....
I have a motor out right now, and have a pic.
1st... there is 4 (large) bolts needed to remove the head...2 of them are inside (which you found)..the other 2 are on the outside....the sticking feeling on removing the 2 inside ones are most likely binding from not having the outside ones loose or out..

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  • mortimor

Posted September 06, 2015 - 09:48 AM

#3

Oh, and to answer your question to #2...i nearly stripped the same bolt too..
You have to just wiggle on the closed end of a 12mm , ...make sure its level and on the good...and really make sure youre turning it the right direction...(that was my mistake..
I took a pic. ....turn the handle to the left..

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  • YZ Yankee

Posted September 06, 2015 - 10:35 AM

#4

Oh, and to answer your question to #2...i nearly stripped the same bolt too..
You have to just wiggle on the closed end of a 12mm , ...make sure its level and on the good...and really make sure youre turning it the right direction...(that was my mistake..
I took a pic. ....turn the handle to the left..

Thanks for the quick reply. In regards to item 1. I did remove the other 2 bolts that you mentioned. Maybe I'll put them in , tighten a little and try to pull the one binding , out first.
#2. I felt the closed end wrench slipping, didn't want to strip it. Maybe a better quality wrench will help.
How are you going to torque that when it's time?

  • YZ Yankee

Posted September 06, 2015 - 11:57 AM

#5

Okay... good tools are a must. Just realized my open end wrenches are junk. Just bought a Husky set, no trouble with that nut!

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  • mortimor

Posted September 06, 2015 - 12:05 PM

#6

Alright..good to go!
Glad to hear it..

  • Birdy426

Posted September 06, 2015 - 09:38 PM

#7

How are you going to torque that when it's time?

 

Motion Pro makes a dog-bone wrench...12mm on 1 end, 13 mm on the other, 3/8 square drive hole (for a torque wrench) in the middle.

 

My guess is the one head bolt threads are grabbing the edge of the hole in the head gasket...should be noting else holding that bolt in as long as the threads are fully dis-engaged.



  • mortimor

Posted September 06, 2015 - 10:03 PM

#8

That sounds like a good plan...i was just going to do it without one..
That bolt issue is baffling to me...sounds bent though..

  • YZ Yankee

Posted September 07, 2015 - 06:09 AM

#9

I tilted it a little and it came off.. not sure why it was catching.
Looks like I'll be ordering new piston and rings. The reason I started this is due to coolant in my exhaust and oil in the radiator. I was advised it was a headgasket. As I began to remove the head bolts, I found one totally lose. I also need to check valve clearances. Found the middle intake valve with less than. 006mm clearance, should be .10 to .15.

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Edited by YZ Yankee, September 07, 2015 - 06:09 AM.


  • Birdy426

Posted September 09, 2015 - 05:45 PM

#10

I tilted it a little and it came off.. not sure why it was catching.
Looks like I'll be ordering new piston and rings. The reason I started this is due to coolant in my exhaust and oil in the radiator. I was advised it was a headgasket. As I began to remove the head bolts, I found one totally lose. I also need to check valve clearances. Found the middle intake valve with less than. 006mm clearance, should be .10 to .15.

Learn from my mistakes...any time you replace the head gasket on one of the 5 valve motors, have the head surfaced.  If you don't, you'll be chasing blown head gaskets until you do...



  • YZ Yankee

Posted September 09, 2015 - 06:16 PM

#11

Learn from my mistakes...any time you replace the head gasket on one of the 5 valve motors, have the head surfaced.  If you don't, you'll be chasing blown head gaskets until you do...

Thanks for the tip'






 
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