Author Topic: Should I replace my valve guides - CB550F  (Read 1061 times)

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Offline psykod

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Should I replace my valve guides - CB550F
« on: April 05, 2009, 04:03:26 PM »
I'm in the middle of a rebuild and have taken the head to a local motorcycle shop for a mild port.  While removing the valves during the head disassembly, one of them was a little difficult to pull through but not thinking, I pulled it through anyway. 

After I inspected the valve, I noticed a small burr below the groove on the stem.  Now I'm worried that I may have damaged the guide but I can't see anything wrong with it.  The head itself has 47k miles on it. 

The shop owner says he doesn't see anything wrong with any of the guides and doesn't recommend I replace them because the seats would probably have to be re-cut and they look good right now.  The head is getting new intake and exhaust valves and a new Webcam cam as well as a port and polish.

Should I follow his advice and not replace the guides or go ahead and replace them and re-cut the seats?
1977 CB550F.  Mostly Stock.

Offline bwaller

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Re: Should I replace my valve guides - CB550F
« Reply #1 on: April 05, 2009, 04:31:47 PM »
The best way to know for sure is to check valve/guide wear with a dial indicator.

I was cleaning a head for re-use and with everything clean and no oil residue discovered there was excessive wear and this on a 20,000 mile head. I fiqure this is unusual.

Check with new valves and see.



Offline MRieck

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Re: Should I replace my valve guides - CB550F
« Reply #2 on: April 05, 2009, 06:23:42 PM »
I'm in the middle of a rebuild and have taken the head to a local motorcycle shop for a mild port.  While removing the valves during the head disassembly, one of them was a little difficult to pull through but not thinking, I pulled it through anyway. 

After I inspected the valve, I noticed a small burr below the groove on the stem.  Now I'm worried that I may have damaged the guide but I can't see anything wrong with it.  The head itself has 47k miles on it. 

The shop owner says he doesn't see anything wrong with any of the guides and doesn't recommend I replace them because the seats would probably have to be re-cut and they look good right now.  The head is getting new intake and exhaust valves and a new Webcam cam as well as a port and polish.

Should I follow his advice and not replace the guides or go ahead and replace them and re-cut the seats?
The seats would absolutely need to be re cut with new guides. The word "probably" doesn't even figure into it. Lengthwise grooves will ultimately let in more oil even with the new seals. Considering the cost of new valves I'd put in guides and cut the seats. That's just me but the seats on these old bikes have 45 degree widths all over the place.....and that's from the factory. I'd start fresh with new stuff and not think about it again....just my opinion.
Owner of the "Million Dollar CB"