Valve guid/Valve stem clearance?

[offroadeast]

How much clearance should there be in a valve guide?

I am going to replace all of the valve train in my cylinder head(05 YZF450). I know that after the new guides are installed they need to be reamed to the proper size. How much bigger should the opening in the guide be compared to the valve stem diameter????

Also, is there drawings of valve shapes available anywhere(I am going to use Kibblewhite SS valves) to cut the valve seats to?

Any help will be great!!!!!

 

[Ol'89r]

(05 YZF450). I know that after the new guides are installed they need to be reamed to the proper size. How much bigger should the opening in the guide be compared to the valve stem diameter????

Also, is there drawings of valve shapes available anywhere(I am going to use Kibblewhite SS valves) to cut the valve seats to?

QUOTE]


Intake. 0.010 - 0.037 mm
.0004 - .0015 in.
Wear limit. 0.08 mm .003 in.

Exhaust. 0.025 - 0.052 mm
.001 - .002 in.
Wear limit. 0.10mm .004 in.

Those figures are for a YZF426 but, should be in the ballpark.

Not sure where to find drawings of the valves but the 'stock size' Kibblewhite valves are the same shape and size as the stock valves.

 

[Rich Rohrich]

The Yamaha service manual has drawings with enough information to cut the valves seats to the proper dimensions.

 

[SFO]

You say new guides, are you talking about oem guides? You are going to have fits trying to ream the nickel bronze guides that kmpi offers. They need to be honed to size. Are you doing all the installation and machining? I size my guides to my serdi pilots which have the clearance I want. I set up kmpi guides with .001" clearance on the intake and .0015" on the exhaust. I make sure my guide bores are clean too, it is very easy to get a buggered up guide bore which makes the rest of the process infinetly more work. I preheat the head on a hotplate to help the aluminum give up its hold on the iron guides. If you are running the kmpi valves I hope you also are running their spring kit.