Topic: Rebuilding a F2/3 head

[fatmatt650]

Thanks for the info Pat! Is the rebuild you describe appropriate for a street/touring motor or is it more of a racing application. I don't mind paying a little more for some extra peace of mind but hate to waste money on something that I'll never need.

[scottly]

A series of video instructions here:

<iframe width="420" height="315" src="

frameborder="0" allowfullscreen></iframe>

There are several errors in the video about cutting the valve seats. For example, the 45 is always the first angle cut; the 60 and 30 cuts are used to adjust the contact area on the valve face. The back and forth motion of the cutter in the video will result in a "wavy" cut on the seat, since the individual cutters are sweeping over the same areas over and over. A smooth rotation in the cutting direction would give a better sealing surface.

Having actually done this, rather than theorizing, the back and forth motion creates a smoother surface requiring less lapping.  The key is to overlap each rotation and to move the cutter each time.  A final sweep all the way around will indicate the cut is smooth if it doesn't grab or drag the cutter.  It is all in the feel and the back and forth motion is ideal.  As far as which surface to cut first, it does not matter at all, each surface is cut lightly at first and then the contact band adjusted with subsequent cuts.  It is always best to base your responses on actual results rather than just wanting to type something and seem informed.

I suggest you re-read the Neway instructions. You must have missed the parts where they said "Turn clockwise", and "Always turn clockwise".

[scottly]

No rebuttal King Rigid? I only am bumping this due to the thread about bogus "how to"videos.
BTW, how long have you been doing valve jobs? I was trained in proper valve/seat resurfacing 40 years ago...

[chewbacca5000]

A series of video instructions here:

<iframe width="420" height="315" src="

frameborder="0" allowfullscreen></iframe>

There are several errors in the video about cutting the valve seats. For example, the 45 is always the first angle cut; the 60 and 30 cuts are used to adjust the contact area on the valve face. The back and forth motion of the cutter in the video will result in a "wavy" cut on the seat, since the individual cutters are sweeping over the same areas over and over. A smooth rotation in the cutting direction would give a better sealing surface.

Having actually done this, rather than theorizing, the back and forth motion creates a smoother surface requiring less lapping.  The key is to overlap each rotation and to move the cutter each time.  A final sweep all the way around will indicate the cut is smooth if it doesn't grab or drag the cutter.  It is all in the feel and the back and forth motion is ideal.  As far as which surface to cut first, it does not matter at all, each surface is cut lightly at first and then the contact band adjusted with subsequent cuts.  It is always best to base your responses on actual results rather than just wanting to type something and seem informed.

I suggest you re-read the Neway instructions. You must have missed the parts where they said "Turn clockwise", and "Always turn clockwise".

Scotty,
I agree I thought the video was great making a complex topic easy and accessible.  I have a CB750 head and would like to get Neway seat cutters used in the video as I need to recut the seats on a few heads for engine rebuilds I am working on over the winter.  Can give me the part numbers for the following Pilot, T-Handle, 60 Degree, 45 Degree, 30 Degree it would be most helpful.  Also is the author using 60,45,30 for both intake and exhaust seats?

Much Thanks!

[chewbacca5000]

Never Mind I found my own answer.  Kingcustomcycle got back to my and his response is posted on the video.

A few of you have asked about the cutters and tools used. They are Neway CU128, CU124, cutters and a 120-6.5 mm Pilot. The nylon 'T" handle is a universal unit sold by Neway also. The total bill will run around $275. A good investment even when doing one head. Both Honda intake and exhaust valves have a sealing surface of 45 degrees with a 30 and 60 degree narrowing/positioning cut