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Zakrad_u

How bad are these valves out?

29 posts in this topic

This is an 09 yz450. The bike has a LOT of hours on it with no valve adjustments. It is pretty damn hard to start so they are finally being done. Here is what I came up with.

 

Looking from the back of the bike forward, the intake valve left to right are .077, .077, and .127mm . The .077s I am unsure of, the smallest feelers I have are .004" (.127mm) and they would not fit so I am assuming .05mm (.002") would fit.

 

The exhaust left is .203 and right is .152, yikes....

 

What does it sound like..?

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Hmm well buy a shim kit and be done I have never in my life seen shims wear evenly haha. But yeah shims are pretty cheap just make sure they are a good brand.

Yzs are pretty bullet proof so I'd say your engines okay

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This is an 09 yz450. The bike has a LOT of hours on it with no valve adjustments. It is pretty damn hard to start so they are finally being done. Here is what I came up with.

 

Looking from the back of the bike forward, the intake valve left to right are .077, .077, and .127mm . The .077s I am unsure of, the smallest feelers I have are .004" (.127mm) and they would not fit so I am assuming .05mm (.002") would fit.

 

The exhaust left is .203 and right is .152, yikes....

 

What does it sound like..?

Clearances are easily rectified. What are the shim sizes / thicknesses?

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Looks like a valve job in your future. At this point, nothing is more than .5mm out, so you can try reshimming, but you will want to recheck them after each ride for the next little while to see if they will hold at the new setting. If they continue to close up, they're shot.

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Sounds good thanks.

 

Am I better off ordering the shims I need or the whole $80 hotcam kit.

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Just the ones you need.  The trouble with the kits is that they cover a size range that you will never use on a YZF.  If you want to have a selection around, you can buy two of the "refill kits" that each have 4 shims each of 6 sizes that could be used in your bike for $30 each.

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Just the ones you need.  The trouble with the kits is that they cover a size range that you will never use on a YZF.  If you want to have a selection around, you can buy two of the "refill kits" that each have 4 shims each of 6 sizes that could be used in your bike for $30 each.

Where do I get that kit?

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That's where calipers come in handy.   :thumbsup:

 

 

21.gif

I figured lol where can I get one and what price am I looking at?

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Well, like most anything, you can spend as much as you want.

 

I've got a couple of Mitutoyo's that were a bit pricey.

 

However, I've seen some of the dial calipers from Harbor Freight be accurate enough for this work and I think they paid about $10 for them.

 

Won't be hard to determine if they're accurate enough: take some marked shims and measure them. If they match the markings then you're close enough for gubmint work. 

 

21.gif

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I went to lowes and got a 3" digital caliper. Seems to be very accurate down to .01mm.

 

So heres what I came up with.

 

Here is the clearance I got with the feelers.

 

Intake from left to right .

.077 - .077 - .127

Exhaust

.203 - .152

 

Here are the shims in the bike.

Intake

1.78 - 1.80 - 1.80

Exhaust

1.82 - 1.85

 

So I figured what I need is this, just want clarification here.

 

Intake - Needed

1.75 - 1.75 - OK

Exhaust - Needed

Ok - 1.80

 

 

Another thing I was wondering is it fine to reuse shims If I have the size I need to replace others with?

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No sealant.

 

"Shuffling" old shims from one valve to another to adjust them is perfectly fine unless the shim is somehow worn or damaged to the point it shouldn't be used.  Hardly ever happens.

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No sealant.

 

"Shuffling" old shims from one valve to another to adjust them is perfectly fine unless the shim is somehow worn or damaged to the point it shouldn't be used.  Hardly ever happens.

Ok thanks, are  the sizes I posted the correct ones?

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The shims in the kits I have seen are in multiples of 5. Are the other shims ending in, say 6, the original from yamaha?

I ask because the 09 I bought used has 68 hrs on it now. I checked them for the first time today. Basically wondering if that was the first time adjusted judging by the odd shims. Trying to get an idea how far they move and how fast.

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