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Valve replacement procedure

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Do I need to do anything to the seats when I replace the valves.

Assuming that the seats "look" OK, is there any machining that "must"

be done.

Like do I have to cut the seats ????

Or can I just install the new ones and be good to go. :naughty:

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Unless you have a TON of hours on it, the stock seats are probably good to go. You can tell visually if you know what to look for. Mine were perfect at 35 hours.

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Or can I just install the new ones and be good to go. :naughty:

You probably already know this, but you should also install new springs and seals with the new valves.

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You probably already know this, but you should also install new springs and seals with the new valves.

Ooops....so very true.

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thanks for the info.

So I am assuming that as long as the seats do not look cracked, pitted,

or in anyway deformed, I am good to go ????

I guess want I need to know is if they visually look OK, not to worry.

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thanks for the info.

So I am assuming that as long as the seats do not look cracked, pitted,

or in anyway deformed, I am good to go ????

I guess want I need to know is if they visually look OK, not to worry.

That's a good question and one that I will be asking shortly as well. I hear a lot of people saying things like "I had my head reworked", and "I had the valve seats touched up". I'm a mechanical idiot and that's like reading Chinese to me.

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Assuming that the seats "look" OK, is there any machining that "must" be done.

You probably can go by how the seats "look", but it's probably worth your time to have a qualified and trusted engine machinist look them over while you have the head apart. Good engine guys can pick up on a lot of details that we normal people don't see; things like guide to seat eccentricity. Plus, the good ones are so busy, they won't try to sell you anything you don't need.

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"seat eccentricity" It's actually "concentricity" or having the same circle center. You can try putting the valves in if you do it yourself and pour a little gas in the intake and exhaust ports. See if any gas seeps through around the valve from the piston side (this is the poor mans way but is effective). It is REALLY best if you have a qualified person true up the seats as long as you have the thing apart, but do NOT let them "lap" the valves or they're junk. You might as well put new springs, retainers, seals and cotters in too as they are known to fail by pulling the end off the valve at the retainer. :naughty:

Wasn't trying to be a smart a$$ either Skip

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Thanks for all the good info ....

I will do the "gas' test after installing.

And "No" lapping..... :naughty:

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"seat eccentricity" It's actually "concentricity" or having the same circle center.

Actually, I meant eccentricity, as in not having the same center. That is the issue you'd want a machinist to identify and fix. To be even more technical, they should actually be coaxial; as in having the same axis of symmetry. But most people use eccentricity/concentricity. BTW, no smart a$$ assumed :naughty: .

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OK potato tomato it's all good. I'm eccentric myself :naughty: I use cutters instead of stones to do my seats, it's all I have used for years. I also cut the seats 1 degree off from the valve angle then go 60 degrees inside and 15 on top. Hardest thing was to find a 5mm pilot for my cutting tool.

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Maybe a dumb question but how do the valve seals go in? :naughty:

The end with the bigger hole goes down on the valve guide, the small hole goes up to ride on the valve

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You might as well put new springs, retainers, seals and cotters in too as they are known to fail by pulling the end off the valve at the retainer. :naughty:

This I did with my new 2005 spec head, everything was new except I reused the camshaft. That's it. The retainers and spring seats don't add too much...

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therapture---did you have to ream the new guides? or is everything good to go.

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therapture---did you have to ream the new guides? or is everything good to go.

Everything was good to go. Guides and stems were smooth fit, no binding, no slop...

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The intakes have a thin coating on them that is essential for long valve life. Lapping will at least remove some of this coating.

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If you mean is doing a valve overhaul easy? The engine is very easy to work on except the @%#^@ carb..it sucks.The only special tool you will need is a valve spring compressor,,,,the rest can be done with common mechanics tools. I would suggest you get a manual so you know how to check some of the tolerances in the top end and understand the process. If you seats are bad you will have to have them reconditioned also but they should be OK unless you've run the engine way past when the clearances have closed.Its actually pretty easy to do. You should have some common sense mechanical ability to tackle the job however and replace the piston while your in there. :)

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