Full Rebuild on 06YZ450F after 246hrs with photos


29 replies to this topic
  • sacfelix

Posted February 23, 2010 - 10:16 PM

#1

Well, it is finally time to do the rebuild after 246hrs of original engine time. The motor still ran great but I rather do it now than pay for it later. Here is my motor in the engine stand I built.

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I started with the magneto side first.

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I removed the flywheel and loosened the balancer nut but did not remove it.

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I then rotated the motor and started on the other side

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Start by removing the clutch assembly

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Dont forget to remove the clutch rod

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You then remove the right side crankcase cover

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I removed all the gears but the right side counter balancer. I then broke loose the counter balancer nut and the nut on the crank and removed those gears as well.

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Its important that you note the placement of the gears but they can only go on one way.

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I then removed the oil pump, shift assembly and shift shaft before going back to the other side.

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I went back to the magneto side and removed the counter balancer

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I then focused on the top end by removing the cam chain tensioner

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Well thats as far as I got so I will update as I finish. Later!


PII:http://www.thumperta...8905&highlight=
PIII:http://www.thumperta...8907&highlight=
PIV:http://www.thumperta...8908&highlight=

Edited by sacfelix, February 23, 2010 - 11:12 PM.


  • sacfelix

Posted February 23, 2010 - 10:21 PM

#2

Continue from part I

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I removed the cams, valve buckets and valve shims noting what shim went where

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I then went back to the magneto side and removed the cam chain guide and cam chain

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I then removed the head bolts

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Removed the head by tapping it with a rubber mallet

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And then the cylinder and piston

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I removed the neutral switch and made a diagram for the crankcase bolts

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I then split the cases exposing the inner workings

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I removed the tranny, shift drum, and crank with the crankcase splitter I made. Dont laugh at it!

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I then removed the oil pick up, old crank bearings and after a good cleaning I put the crank halfs in the oven. The crank and crank bearings were in the freezer for the past 3 hours while I was tearing it apart. I pulled one case out of the oven at a time and the bearings slid right in. I then put the left crankcase back in the oven and once warm the crank slid right in the bearing

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Well thats all for now but I will update as I go along.

  • sacfelix

Posted February 23, 2010 - 10:24 PM

#3

Continue from PII.

Now that the crank was installed I put the tranny back in lubing every thing as I went along. I also replaced all oil seals and all new gaskets

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Before I put the cases together I applied Yamabond to both halfs

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Then mated both halfs and bolted together

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I then placed the motor back in the engine stand for reassembly

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I started reassembly with the right side case

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And the magneto side

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I installed the neutral switch making sure not to loose the little pieces

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I then took the new cylinder and cleaned it . After a good drying I oiled down the cylinder and gapped the rings. I then installed the rings on the piston and installed the piston in the cylinder.

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Well thats all for now but I will update as I go along.

  • sacfelix

Posted February 23, 2010 - 10:30 PM

#4

I then mated the piston and cylinder to the lower end after I put on a new base gasket.

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I cant go no further until I get my head back because Im getting it ported and polished so stay tuned.

  • ThumperKid250F

Posted February 24, 2010 - 06:24 AM

#5

nice job.. i love my 06 motor.

i just did a complet rebuild after my wrist pin snaped on me. ( dont get a wiseco piston) heres what i did

all new valves
mild port and polish
CP HC piston 13.5
sent my crank to falicon and they lighten polished fully welded and blueprinted and they put a 6mm long rod on it, then balanced it to my piston..
then i put a whole hinson clutch kit ( basket, hub pressure plate and stock yamaha plates,

let me tell you putting that long rod in it made this bike a low and mid rang monster and i dident loose really anything up top.

good luck with your build:thumbsup:

btw who did you send your head too?

  • hillclimbguy

Posted February 24, 2010 - 08:02 AM

#6

I like the engine stand. Sure beats working on the bench with the motor sliding around.

  • grayracer513

Posted February 24, 2010 - 08:10 AM

#7

No trans bearings, eh? :thumbsup:

  • ThumperKid250F

Posted February 24, 2010 - 10:31 AM

#8

No trans bearings, eh? :thumbsup:


if your talking about mine then yes all the bearings in the bottem end were replaced with stock yamaha bearings when we spilt the cases..

  • grayracer513

Posted February 24, 2010 - 10:32 AM

#9

I'm not. I'm talking about the OP's job.

  • ThumperKid250F

Posted February 24, 2010 - 11:02 AM

#10

I'm not. I'm talking about the OP's job.


gotcha..

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  • tek_01

Posted February 24, 2010 - 06:58 PM

#11

Good write up, doesn't seem too much more difficult than my old xr bottom end.
So no gasket between the halves? thats interesting

Would of been a pretty expensive little exercise but you know its going to last

  • sacfelix

Posted February 27, 2010 - 11:51 AM

#12

I got my head back and went to install the cams last night. I used redline assembly lube, the clip that goes on the bearing slid right in and the cap slid right on with no problems. After I torqued them to spec I checked the valve clearance and set the valve clearance, the exhaust cam turns freely but the intake cam is hard to turn. I removed the intake cam and double checked that every thing was in place and it looked good so I reinstalled every thing again and still the same problem. Any input would be appreciated. Thanks!

  • grayracer513

Posted February 27, 2010 - 03:16 PM

#13

This isn't too unusual. Run down to the auto parts house and pick up some Plasti-Gauge for measuring clearances under .003". The dig out the manual and look up checking the clearance on the camshafts.

  • Aka.Goose

Posted February 27, 2010 - 03:33 PM

#14

I trip on people who rebuild their motors without washing them first! hehe
Nice work, thanks for posting, and keeping us updated until break in!

  • NortonMoto

Posted February 27, 2010 - 06:16 PM

#15

I concur!



I trip on people who rebuild their motors without washing them first! hehe
Nice work, thanks for posting, and keeping us updated until break in!



  • sacfelix

Posted March 01, 2010 - 10:28 PM

#16

I checked the clearance on the cam to to cam cap and they measured .038mm.

  • grayracer513

Posted March 02, 2010 - 10:56 AM

#17

I checked the clearance on the cam to to cam cap and they measured .038mm.

So, that's on the tight side, but within specs. Check the runout, and if it'd OK, run it.

You could also take the cam to a machinist and ask him to polish .0004-.0005" (count the decimals) off of it, too, and that might be a better way to go, but it should work as is.

  • sacfelix

Posted March 03, 2010 - 09:26 PM

#18

So, that's on the tight side, but within specs. Check the runout, and if it'd OK, run it.

You could also take the cam to a machinist and ask him to polish .0004-.0005" (count the decimals) off of it, too, and that might be a better way to go, but it should work as is.





What are you refering to as "the runout"?:thumbsup:

  • grayracer513

Posted March 04, 2010 - 12:10 AM

#19

Runout is the amount a rotating part or assembly moves off center or out of plane as it turns. See page 4-25 of your manual.

  • Slick_Nick

Posted March 20, 2010 - 07:57 AM

#20

Good job man! Keep it up!





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