Honda CX 500 Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
52 Posts
Discussion Starter · #1 ·
My new 78 CX500 (79 engine) is leaking oil from the spark plug drain hole on the left cylinder. Reading some other threads and other sites, it's obvious to me that this is an issue with the plug hole gasket. I have procured a new gasket. Being new to working on bikes, is replacing this gasket as simple as pulling the cover and replacing the gasket?
 

·
Super Moderator
Joined
·
15,414 Posts
Simple as that. But the bolts only need to be hand tight. Any torque could strip the hole or break the bolt. They get torqued to 6 pounds otherwise.
 

·
Registered
Joined
·
2,282 Posts
Don, if you can hand tighten bolts to 6 ft lbs, I don't want to shake hands with you. I believe they need to be past hand tight, but these bolts are shoulder style that only will go so far in before the shoulder contacts the head. That keeps the gaskets from squishing too much when people think that all bolts should be tightened within a spec of breaking and then turn it another half turn. If you grip a 3/8" ratchet over its head and then use that grip to tighten, you probably won't strip them or any other small bolts.
 

·
Premium Member
Joined
·
2,510 Posts
Many valve cover bolts have been snapped due to being over-tightened. If uncertain, this is one where it is probably best to err on the loose side and tighten slightly more if there is a leak.



I usually just use a small torque wrench set to 6 lb-ft.
 

·
Super Moderator
Joined
·
15,414 Posts
You mean you cant hand tight 6 pounds. That's like the equivalent of a screwdriver.



After doing it who knows how many times I know just to turn it in and where there is resistance then you stop.



A 1/4 drive ratchet with 5 inch handle is your best friend in many cases with these bikes.
 

·
Registered
Joined
·
122 Posts
Many valve cover bolts have been snapped due to being over-tightened. If uncertain, this is one where it is probably best to err on the loose side and tighten slightly more if there is a leak.



I usually just use a small torque wrench set to 6 lb-ft.


Very true. I would rather wipe up a little oil than wipe up some broken valve cover bolts.
 

·
Registered
Joined
·
2,282 Posts
Don, the way I read your post, I thought you were just using your fingers and thumb to turn the bolt. I can probably do 6#, even with old Arther in my hands.
 

·
Registered
Joined
·
1,871 Posts
I use a short little box end wrench, and hold it with my finger tips so I don't have much leverage at all.  I feel better doing it that way than trusting in a torque wrench.
 

·
Registered
Joined
·
52 Posts
Discussion Starter · #9 ·
Thanks, guys. I appreciate the help. I'll plan on doing this tomorrow and erring on the side of caution with tightening the bolts.
 

·
Super Moderator
Joined
·
15,414 Posts
Don, the way I read your post, I thought you were just using your fingers and thumb to turn the bolt. I can probably do 6#, even with old Arther in my hands.


Yeah hand tight not finger tight.



You might not want to do it with old Arther in your hands if there are children around. I think the police give a pretty ugly ticket for indecent exposure.
 

·
Registered
Joined
·
52 Posts
Discussion Starter · #11 ·
I did this repair and while it decreased the leak, I am still leaking a tiny bit of oil from the plug hole drain. I tried it again with some gasket seal, which cut down on the leak more, but there is still a slight leak. I'm wondering if the gasket isn't quite right. It seemed to fit the cap pretty loosely. Should it fit the cap fairly tightly?
 

·
Registered
Joined
·
102 Posts
some of those round spark plug hole gaskets are rubbish, you could try putting a little hylomar blue on the rocker cover and letting it set for a few minutes, then placing the ring in and let it stick for a while. torque up the bolts to 6 ft/lbs using an accurate torque wrench. whatever you do - don't try blocking the oil drain hole. I did this once just because I wanted to ride and my new gaskets hadn't arrived yet and after a few minutes I had oil spewing out of the plug caps!
 

·
Registered
Joined
·
8,423 Posts
some of those round spark plug hole gaskets are rubbish, you could try putting a little hylomar blue on the rocker cover and letting it set for a few minutes, then placing the ring in and let it stick for a while. torque up the bolts to 6 ft/lbs using an accurate torque wrench. whatever you do - don't try blocking the oil drain hole. I did this once just because I wanted to ride and my new gaskets hadn't arrived yet and after a few minutes I had oil spewing out of the plug caps!




Ditto.I use clear silicone RTV that I have in one of those big sealer guns in the groove.This is not so much to seal but to hold the rubber seal in place so it doesn't malform/drop when fitting.Same with the spark plug rubber seal but wipe off excess after leaving it to dry for half-an-hour.
 
1 - 17 of 17 Posts
Top