305 Head Gasket-What Caused This?

jcspc · Post by **jcspc** » Sat Aug 29, 2009 6:34 pm

I had put my motor together this winter and this summer after riding around it developed a leak. I pulled the motor today and took the head off and this is what I found, 2 splits in the gasket right next to the oil ports... did I use a cheap gasket or is something else happening.

Also, since I need to replace it, and I don't want to buy a complete gasket set, where can I get just the head gasket? I didn't disturb the base gasket so I don't think that needs replacement and those plate gaskets came off nice and clean. I believe those are reusable.

My bike is almost done...

davomoto · Post by **davomoto** » Sun Aug 30, 2009 11:16 am

Did you have the o-rings over the dowels? I know western hills honda has the head gasket seperate, but it's spendy.

davomoto

jcspc · Post by **jcspc** » Sun Aug 30, 2009 11:56 am

Yes I did, and I used slightly over-sized o rings out of my plumbing truck. They were pretty well smashed, in other words, they didn't hold their shape very well. I thought o-rings were o rings. I used the over-sized o rings on advise from Ed. They weren't humongous but they were bigger. When I put this back together again, I don't want it to leak (really? duh) Got a link or sure fire suggestion for the rebuild?

jcspc

davomoto · Post by **davomoto** » Sun Aug 30, 2009 12:54 pm

I suggest using correct o-rings. Here's a link for a top end gasket set, a complete gasket set, and another for head gasket only. Also link for western hills honda. I use a small amount of hondabond around the o-rings

davomoto

http://cgi.ebay.com/ebaymotors/honda-cl ... .m20.l1116

http://cgi.ebay.com/ebaymotors/CB77-HON ... 06.c0.m245

http://cgi.ebay.com/ebaymotors/HONDA-CB ... .m20.l1116

http://cgi.ebay.com/ebaymotors/honda-cl ... .m20.l1116

http://www.westernhillshondayamaha.com/

jcspc · Post by **jcspc** » Sun Aug 30, 2009 1:50 pm

Thanks davo,
Is hondabond a silicone or will silicone be ok to use?
Also, I think that the failed head gasket came from a DK gasket set. Don't think I'll go that route again. I Guess that NOS one for 35.00 looks good...Maybe I'll check my local dealer.
How much silcone is too much.
I fell pretty dopy asking this stuff but I don't want another leak.
Thanks for your help

Jeff

jensen · Post by **jensen** » Sun Aug 30, 2009 2:53 pm

Hi,

Are you sure the head and cilinder surfaces are flat within specification ?

jensen

e3steve · Post by **e3steve** » Sun Aug 30, 2009 3:06 pm

I'd be inclined to be in agreement with Jensen. As regards using goop, O-rings aren't designed to be gooped, as the 'wrong' goop will cause the composition to break down under stress/heat. And I know Ed will slap your legs when he reads this. On the other hand, davo is a respected member here with a lot of experience, so if you are going to use anything, use Hondabond, not silicon!