Author Topic: Head gasket  (Read 739 times)

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Offline emlupi

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Head gasket
« on: October 10, 2018, 06:34:59 am »
Good morning,
I have a 1972 CB750K2 that is all stock and running well. Recently I have noticed that there is a very light oily sheen appearing around the perimeter of the head gasket after riding. It looks like oil is slowly wicking through the gasket. This only happens while the motor is running. It doesn’t happen while the bike is sitting. It doesn’t drip or run, it just gets a little damp around the gasket.

The bike had sat for many years before I owned it so I’m assuming that the gasket has deteriorated and is now beginning to leak? I guess this means that I will soon be looking at doing a top end rebuild.

Anyone else with a similar experience or advice I would be happy to hear from you. Thanks

Offline beemerbum

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Re: Head gasket
« Reply #1 on: October 10, 2018, 08:14:58 am »
My 1977 K7 does the same thing as well as the cam cover. Not even Soichiro could install gaskets that would last 40 plus years in an air-cooled motor.

Offline PeWe

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Re: Head gasket
« Reply #2 on: October 10, 2018, 08:33:21 am »
Tighten the head nuts demands so much work. Very heavy too if frame has no frame kit :(
Tighten them might help.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline flybox1

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Re: Head gasket
« Reply #3 on: October 10, 2018, 09:21:31 am »
If it aint soaking your riding pant leg(s), its not worth the trouble.
Wipe it down after a ride, and check that your oil tank is topped off.

...you can also get a few feet of cotton rope, to push in between the fins around the gasket seam. 
Change it every so often.  That'll buy you at least a year  ;D
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline emlupi

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Re: Head gasket
« Reply #4 on: October 10, 2018, 01:04:03 pm »
Thanks for the replies. It is not really losing that much oil. I check it after riding and the last time it was down about 4 ounces after 300+ miles. Definitely not making any mess. I only noticed it while giving the bike a good wipe down after riding. I guess I will keep an eye on it but plan to eventually go in and make repairs.