When to replace valve cover and adjustment cover gaskets

If it's broken or just needs tweaked

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When to replace valve cover and adjustment cover gaskets

Postby juntjoo » Wed Jan 09, 2019 5:25 am

I've got leaks from mine which I partially remedied torqing down on them a bit beyond spec(probably not good) which helped a bit but not entirely. The gaskets aren't old at all but I've removed the covers a few times for hiding valves and other work so I'm wondering how quickly, or after how many removals, they lose their effectiveness. I have a fresh set of gaskets but before using them I just wanted to make sure the current ones definitely have worn out despite their young age and good appearance before using the new ones and that there couldn't be other issues. I can't really imagine something else (maybe my torque wrench is off?) is king on but just wanted to make sure. How often do you have to replace these gaskets(main head cover and side adjustment covers)? Thanks
82" cb650 Nighthawk

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Re: When to replace valve cover and adjustment cover gaskets

Postby Volker_P » Fri Jan 11, 2019 2:38 am

The center cover (and at Z-model and '79 also side covers) are a bit special.
The center cover is fixed with two of what you called "weird looking ufo bolts" some time ago. :lol:
If you turn them in, the metal step at their bottom fixes and limits their position in the thread. More torque does not make any difference and sense here, it may only strip the thread for nothing.
In fact it is a fixed gap and the rubber parts just have to fit. The tension to fix the cover and seal is at the bottom the gasket and on the top the rubber cone around these bolts. If the rubber cones are poor, brittle or worn, you won't get a tight valve cover even with brand new cover gaskets.
Normal bolt side cover is similar, but there it is only the gaskets.

Fix: Bolt on all covers without gaskets and measure the remaining gap. Then measure your gasket thickness.
If you find you need to rasp something a very little bit (!) down, decide for the thread stud and not for the (side) covers.
Cosky's great (free) online manual: http://cosky0.tripod.com

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