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installing new black diamond vavles

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is it nessacary to lap new valves when installing them?

i am a little confused as to what lapping is for.

is it....

a) lapping is done to identify where the valve is sealing on the head, and to ensure that it is a uniform, even seal. ( a diagnostic procedure?)

or

:busted: it is done to wear the valve down to an even surface to ensure a good seal. (an installation type procedure?)

in other words, is it nessacary to lap new valves?

thanks

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You did have the valve seats cut as well didn't you? Then you lap the valves in, to make sure the valves seat into the valve seats.

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will i need to cut the new black diamond vavles to install them or can i just install them striaght up?

when switching from stock valves to black diamonds, is it nessacary to cut the valve seats?

thanks

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The valves are new so, they are fine but, a valve job will include the valve seat to be cut. A three angle grind is best and is the only way to go. Then lap the valves to the seats. Any GOOD mechanic will do it right. Doesn't have to be a motorcycle shop ether/nether.

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so you would cut the valve seat (which is on the head, where the valves make contact when shut?) in a circular manner with the three different angle cutters?

i read about it in the manaul, but i guess i'd have to see a video or see it in person to fully understand it.

i am rebuilding my bike and i do not want to do it half-assed. it is 100% fully OK to not cut the valve seats when installing new black diamond valves on the stock head that has about 50hours or so of use on it?

thanks

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so you would cut the valve seat (which is on the head, where the valves make contact when shut?) in a circular manner with the three different angle cutters?

i read about it in the manaul, but i guess i'd have to see a video or see it in person to fully understand it.

i am rebuilding my bike and i do not want to do it half-assed. it is 100% fully OK to not cut the valve seats when installing new black diamond valves on the stock head that has about 50hours or so of use on it?

thanks

I have been biulding engines for years and would never install new valves on old valve seats (not ground/cut).

Cutting valve seats is just another way for saying grinding the valve seat or resurfacing. There are two angle valve cuts and three angle cuts for the guys that do it right. This is more of something you want to practice at not experiment on your bike with. It would cost little to have a mechanic do it for you. I would never, never install any valve on a valve seat it did not mate with.

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Since you asked and I am a picture/post whore.:busted:

Before.

Note the valve seat erosion where the intake valve had mushroomed out.

IMG_0924.jpg

IMG_0925.jpg

The tools to do the job.

30°, 45°, 60° Neway valve seat cutters, 6.6mm soild pilot, Neway E-Z wrench, tube of Prussian blue oil paint, 2.5mm allen key and new black diamond +1mm valves.

IMG_1120.jpg

From left to Right.

The 45° 607 the 30° 270 and the 60° 608.

Note the different carbide bits and quantity. The cutter with 5 bits cut smoother than the cutter with 3. Also the bits with the serrations all the way across the face cut really smooth but also cut slowly. So a 3 bit cutter with the single edge bits makes for really rough cuts but fast. If you can buy all 5 bit cutters.

IMG_1116.jpg

This is how the tool looks on the head.

IMG_1135.jpg

IMG_1136.jpg

After

I have only completed the intakes.

IMG_1124.jpg

IMG_1125.jpg

So smooth. If I were a valve I would want to mate with this surface.

IMG_1126.jpg

What to look for with the prussian blue.

Nearly done. I want this blue band to be a near perfect as possible. No breaks, no variations in width (1.2mm intake 1.4mm exhaust), no variations on placement. Yes the seat is a bit high on the valve but I want all the life I can get out of these intakes.

IMG_1130.jpg

This seat still needs a bit of work but the placement is right.

IMG_1123.jpg

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Can't explain it any better then that:thumbsup: Lap those puppies in and call it sex. Ahh, I mean mate those puppies or finish the job. All the same I guess?:busted:

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