2006 yz450 Valve Adjustment. What do I need?


7 replies to this topic
  • 4stroked

Posted April 26, 2007 - 08:40 PM

#1

Question

What tools do I need?

How long will it take(1st time)?

Any how too thread or link?

Photos of step by step?

Thanks for your help.

Ben

  • grayracer513

Posted April 26, 2007 - 09:02 PM

#2

http://motoman393.th...ech/valves.html

Or, this, it's for a 250F, but it's the same procedure (the clearance is different!):

http://www.thumperfaq.com/valves.htm

Special tools you will need are your manual, a set of feeler gauges, and, if you have to actually make an adjustment, an inch pound torque wrench.

Note that YZF's are built deliberately with the valves set at the tight edge of the spec. (your intakes will probably all be at .10 mm). This is in spec, and you should not adjust.

Without an adjustment, it will probably take you an hour and a half to do the first one.

  • Desracer

Posted April 26, 2007 - 09:10 PM

#3

If your going to own the bike for a long time buy a shim kit. It will be about $80.00 and has all the shims you will ever need. My local Yamaha dealer never had shims, be the Honda dealer was stocked. The dealer wants $6.00 for each shim so my head was $18.00 for the intakes. So now I have saved money and can sell shims to my friends with the kit.

  • grayracer513

Posted April 27, 2007 - 05:49 AM

#4

If your going to own the bike for a long time buy a shim kit. It will be about $80.00 and has all the shims you will ever need. My local Yamaha dealer never had shims, be the Honda dealer was stocked. The dealer wants $6.00 for each shim so my head was $18.00 for the intakes. So now I have saved money and can sell shims to my friends with the kit.

I've owned my Ti valved '03 for nearly 4 years and haven't needed a single shim.

In the shim kit, you get only 3 of each size shim, and you get sizes you will never be able to use in a YZF.

No more often than you'll need them, just buy what you need from the local Honda dealer (the 9.48mm shims for a CRF are the same). Yamaha dealers rarely stock them because of the lack of demand.

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  • WFOracer

Posted April 27, 2007 - 06:10 AM

#5

Agree with Gray..... also

It's a good idea to run to a Napa store and get some plastigage, it is for checking the bearing surface clearance as well as double checking you torque wrench. The amount of torque that you apply to your cam bolts can change your valve clearances.

  • grayracer513

Posted April 27, 2007 - 09:39 AM

#6

The amount of torque that you apply to your cam bolts can change your valve clearances.

It shouldn't, but what it can do, and often does when the job is done incorrectly, is to change the shape of the bore through the cap/head assembly, and thus the camshaft clearance.

It cannot be stressed enough how important it is to correctly retorque the cam caps to the head. It's not hard to do it right, but you have to pay attention.

> The mating surface of the cap and the head must be clean, and completely free of anything foreign. No chips, dirt, or shop towel lint. Oil is OK.

> The cam cap should be pushed down into place and fully seated BY HAND until the mating surfaces come into contact with the head. The cap needs to fit down over the bearing locater half rings, and the doweling sleeves at the corners. DO NOT pull them into place with the bolts.

> Run all of the bolts in each cap in to the point where they are "just snug" before torquing that cap. Torque the cap in a crossing/circular pattern, starting on the ball bearing end (shown in the manual), and tighten the bolts in 3 steps, starting at 40-45 inch pounds.

> And this is my own recommendation. Some agree, some do not; I don't care. I do it this way: Torque the bolts to 75 inch pounds (6.2 ft/lbs) NOT the listed 86 inch pounds (7.2 ft/lbs). Based on my experience, and the feel for this kind of thing I've developed over more than 40 years, and the fact that the bolts specify oiling the threads, 75 in/lb is plenty; 86 is too much. My opinion, take or leave it.

But anyway, as important as these points are, they're easy to comply with, and the job will go well if you do.

  • WFOracer

Posted April 27, 2007 - 11:02 AM

#7

> And this is my own recommendation. Some agree, some do not; I don't care. I do it this way: Torque the bolts to 75 inch pounds (6.2 ft/lbs) NOT the listed 86 inch pounds (7.2 ft/lbs). Based on my experience, and the feel for this kind of thing I've developed over more than 40 years, and the fact that the bolts specify oiling the threads, 75 in/lb is plenty; 86 is too much. My opinion, take or leave it.


What are the negative effects of tightening to 86 in lbs? The bolts can definitely hand it, not sure why you would want to under tighten them. :applause:
Please explain more....

Thanks

  • grayracer513

Posted April 27, 2007 - 12:48 PM

#8

86 inch pounds on an oiled thread, as is called for in this application is a good deal more than the generic 86 in/lb used on the same 6x1.0 thread in most other places around the bike. In fact, the actual clamping force and tension placed on the bolt and threads can be from 25% higher to nearly double what it would it would be with "clean dry" threads. Too much clamping force in an application like this can pull the mating surfaces up around the bolt, distorting the fit, and can also distort the cam cap in this case.

As I said, it's a matter of experience and feel. I would certainly not suggest under tightening anything, but I don't don't see that I am. I do not like the feel I get from these bolts at 86 in/lb, and I see 75 as being more than adequate. Every YZF I've done, I've done this way, and they all work fine. By contrast, I know of several cases of seized cams and pulled cam cap threads. I'm not going to state categorically that torque was the cause, but in each of those cases, the caps were torqued to 86 pounds.





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