is this head OK to run ? (pics)

S

sandman28

Been Around the Block
While cleaning up my head I saw some slight damage / 'deformation' on one side only.(shown in photos) It does not appear to effect the valves or valves seats in any way. All of that, valve guides and rest of head are good shape. Searching on eBay for possible replacement I noticed alot of head have similar slight damage on one side. Wondering if this head is OK run?, and what causes this? . Piston hitting ?
 

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It's OK to run. The head is aluminum.

Something got into the engine while it was running. Most common culprit is a screw from the carbs.
 
Every high point is and will be a hot spot i wouldnt run it with out dressing it with a die grinder
 
bradj said:
Every high point is and will be a hot spot i wouldnt run it with out dressing it with a die grinder
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Not a huge deal on an aluminum head. Aluminum transfers heat much more quickly than iron or steel.
 
Sonreir said:
Not a huge deal on an aluminum head. Aluminum transfers heat much more quickly than iron or steel.
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Aluminum head yes, but take a better look at the chamber
 
those seats are pretty bad... really bad... so bad I may actually think of scrapping the head, that much constant impact and they very well may have cracks all through them, even getting them recut they may shift around or fracture more after running, i'd say junk it and cut your losses right here
 
Roc City Cafe said:
those seats are pretty bad... really bad... so bad I may actually think of scrapping the head, that much constant impact and they very well may have cracks all through them, even getting them recut they may shift around or fracture more after running, i'd say junk it and cut your losses right here
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I disagree that the head is junk. Seats can't shift around- I will refer to my previous post. I'm not just gonna give to you. Look close. Pitting in the exhaust seat is totally normal from carbon and other debris going through a motor and more so on older vehicles with softer exhaust seats. You will need to have a valve job from your local machine shop
 
cb350... if it seems questionable i'd rather get another used in better shape. all im trying to do with head is simply lap the valves.
 
there is a local place in town that builds vintage race bikes, ill take it there and see what he says. its hard for ya'll to judge from pics. thanks for the feedback.
 
Good idea. It's hard to tell from pics on the internet but those valve seats look like they need cutting, not just lapping.

And the other damage is not helping the cause when there's a bunch of other heads on eBay for cheap.
 
i zoomed the pics, scrap the head
but if you decide to try to recut the seats save yourself the trouble and check the guides first they are lkely worn out as well
it must be done carefully with clean dry guides the procedure is IN THE shop MANUAL
 
If you do end up just throwing it out, I'll pay for postage to have it shipped my way.
 
reds said:
I disagree that the head is junk. Seats can't shift around- I will refer to my previous post. I'm not just gonna give to you. Look close. Pitting in the exhaust seat is totally normal from carbon and other debris going through a motor and more so on older vehicles with softer exhaust seats. You will need to have a valve job from your local machine shop
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dunno man, I zoomed in and that doesn't look like pitting due to combustion or corrosion, it looks like the valve was chomping on something pretty hard, any surface treatment of the seat has probably become fractured from the base metal and those fractures likely carry through into the seat itself, seats don't shift around under normal circumstances, but if its cracked enough to change the cylindricity of the seat, then shifting is a distinct possibility, that or just cracking and starting to fall apart under running conditions
 
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