Topic: How do my Valves and Pistons look?

[The Gurg]

Getting the pistons and valves checked at a machine shop tomorrow. Seeing what you guys think of their visual appearance. Do these look ok?

1975 CB750 K5 33k mi.

[thep1pe]

Pistons are f#*!%d. Can’t see the valve properly.

[rotortiller]

I wouldn't say they were totally pooched until the corrosion is carefully cleaned up and everything measured and closely examined. Must have been lightly seized at one time. I'd smooth out the scratches in the crowns too. I have seen worse in service. Hard to tell the extent of the skirt damage, may be varnish too, a bit of scotch brite might help.

[754]

We can't see  the parts of the valves that matters..

[The Gurg]

Does this photo of the valves help?

[thep1pe]

Unless the pistons were unavailable,I would never use reuse a previously seized piston. The piston could have been seriously weakened due to the heat. Don't let a few bucks saved now turn into a money pit further down the road.

[rotortiller]

I would never use reuse a previously seized piston. The piston could have been seriously weakened due to the heat.

It looks like it was lightly seized by corrosion from sitting and not heat. I see no heat distress here to affect metallurgy.

[The Gurg]

Just got back from the machine shop. Three different guys took a look and they said the pistons and valves look fine. Pistons are within spec. Valves are being ground.

[MRieck]

Just got back from the machine shop. Three different guys took a look and they said the pistons and valves look fine. Pistons are within spec. Valves are being ground.

I wouldn't grind the valve face....it removes the Stellite and you have only fairly soft steel left. They last about 1,000 miles or so after that How about a set of Vesrah valves....they are pretty inexpensive and work OK

[754]

I got at least 7000 on my ground ones.
 I thought Stellite was only used on a few early years, and early F models.