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mark-Thanks again-I still have a couple of questions,
1.how do I refinish the valve seats
2.what do you mean by ream the new valve guides?
3.does heating up the head do anything to the exhaust valve seals that are still in place?
ThanksiDave Laub
Answer -
Hi David!
Note: Refinish valve seats whenever the valve guides are replaced to prevent uneven seating.
Replacing Flanged Guides:
Chill the new valve guides in the freezer for about an hour.
Heat the cylinder head to 275 to 290 degrees F. Do not heat the cylinder head beyond 300 degrees F. Use temperature indicator sticks, available from welding supply stores, to be sure the cylinder head is heated to the proper temperature.
Caution: Using a torch to heat the cylinder head may cause warping. Wear insulated gloves to prevent burns.
Support the cylinder head and drive the old guides out of the combustion chamber side of the cylinder head. Avoid damagaing the head when driving the valve guide out.
Apply oil to a new O-ring and install it onto a new valve guide. Drive the new guide in from the camshaft side of the cylinder head while the cylinder head is still heated.
Let the cylinder head cool to room temperature, then ream the new valve guides.
Replacing Flangeless Type Guides:
Same as above except: Measure and record the exposed height of the valve guide using a pair of vernier calipers.
As always, follow the service manual procedures specific for your MC.
Respectfully,
Mark Shively
Answer -
David
Send me an email, I'll return repair files. mshively1@woh.rr.com
Mark
AnswerDavid: How do I refinish the valve seats?
Mark: If you're not experienced, have a shop or machinist perform this work. They have a saying: "You can pay me now, or you can pay me later."
David: What do you mean by ream the new valve guides?
Mark: You must finish the inside diameter of new valve guides to fit the outside diameter of the valve stems. We use reaming tools to perform this work.
David: Does heating up the head do anything to the exhaust valve seals that are still in place?
Mark: Remove valves and guide seals prior to heating cylinder head.
Check out "Neway" brand valve cutting tools on-line. Perform internet searches for "replacing valve guides." to get an idea of the work involved. The process is about the same for all engines.
Mark Shively
