G80cs head crack

torker · Post by **torker** » Wed Mar 02, 2011 12:00 am

I am having a valve job done on my 1964 g80cs. We noticed a small hairline crack from sparkplug hole to the exhaust valve seat. The crack goes down the sparkplug hole about 1/4" but not into the sparkplug threads. Is this a problem. Do I need to remove the seat and have the head welded? Thanks

chasdev · Post by **chasdev** » Wed Mar 02, 2011 12:00 am

It is a problem and must be corrected.
Depending on your welder and/or machine shop, it may be cheaper to buy a "new" head.

wilko · Post by **wilko** » Wed Mar 02, 2011 10:17 pm

Give us a gander?

torker · Post by **torker** » Wed Mar 02, 2011 11:08 pm

How do I insert my cracked head images?

torker · Post by **torker** » Thu Mar 03, 2011 4:07 pm

Here are two pictures of the cracked head. Tell me what you think?

torker · Post by **torker** » Thu Mar 03, 2011 4:32 pm

Second try for pictures of cracked head http://s1104.photobucket.com/albums/h322/34chop34/

1608 · Post by **1608** » Thu Mar 03, 2011 6:01 pm

Shame, its otherwise a nice clean looking chamber. The head on my G12 has obviously been welded in the same place, before I inherited it. However, the valve seat was loose, so I had the sest replaced at quite some cost. I very shortly afterwards found a second hand head ( in vgc ) for sale and bought it - cost £5. The lesson being, don't rush into an expensive repair as I'm sure there are plenty of s/h heads available.

Don Madden · Post by **Don Madden** » Thu Mar 03, 2011 7:38 pm

You will have to dig through the RHS to find any CS head. Cheers, Don. Edited by - Don Madden on 03 Mar 2011 7:39:28 PM

itma · Post by **itma** » Thu Mar 03, 2011 8:45 pm

why does the Royal Horticultural Society have spare CS heads?

torker · Post by **torker** » Thu Mar 03, 2011 9:30 pm

I talked to the fellow I bought the G80CS from (about 20 years ago). He said that the head had that "crack" back when he did a valve job on the bike. I have rode the bike about 12,000 miles since then. Maybe I have been lucky. The exhaust seat does not seem loose. I guess I will start looking for a head.