leftfield6 
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« on: January 31, 2011, 08:13:16 AM » |
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 I had a smallish oil leak on the front side of my valve cover. Over on the right side front about 2 inches from the corner. Easy fix, right? I buy a new valve cover gasket and set aside a few hours to do the change, following the steps in the factory manual. I'm all proud of myself for getting my hands dirty, that is until the next ride. Old oil leak? Fixed!!  New oil leak? Yep  Exact same place, but on the left side of the engine now. Dammit. So, this seems as straightforward a process as it can be. Any secret sauce I'm missing here. Tips? Obviously I'm pulling it to retry, can I reuse this gasket, or is a one time use kind of thing?
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tomb raider
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« Reply #1 on: January 31, 2011, 08:26:51 AM » |
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That's no good, I have one on each side. Have a new gasket to, I think Gammer said he used a tad bit of RVT as well  .. Makes no sense on it still leaking. You should be able to reuse it many times.. |
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Jimbo
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Munkey
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« Reply #2 on: January 31, 2011, 08:31:55 AM » |
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I had the same problem. Normally I'm against using any kind of sealer on valve cover gaskets but Gammer said he uses a thin layer high temp RTV on his so I did the same and that fixed it.
Also watch how much you tighten those valve cover bolts. Too much and it will squash the gasket out and cause it to leak.
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1985 CB700SC Nighthawk
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muttstang
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« Reply #3 on: January 31, 2011, 09:10:08 AM » |
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I used a little RTV on mine and it has worked well. I put it in the groove on the valve cover itself but not on the other side of the gasket
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1985 CB700SC always a project in process! Cams re-timed ;)
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Brittles
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« Reply #4 on: January 31, 2011, 11:54:43 AM » |
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Interesting as I'll be installing a new gasket on mine in the near future. Hoping to only do it once.
I know the manual doesn't say anything about it but should the gasket be "pre-treated" with motor oil before installation? Like is done on oil filters. I was hoping not to use any type of gasket sealant but I will if need be.
As far as reusing them goes.........the manual says to inspect and replace if neccessary.
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John
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gammer
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« Reply #5 on: January 31, 2011, 12:53:40 PM » |
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What I have found, is that if you use a new gasket, along with new rubber washers for the valve cover bolts, then you probably don't need RVT. If you re-use any or all of those parts, then there is a very good chance you will get a leak without any RVT.
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Bad Boy
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« Reply #6 on: January 31, 2011, 01:54:07 PM » |
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The valve cover hold down bolts have a shoulder on them so you can only tighten them down to a point and they stop. So you can not tighten the cover down any more. Also the rubber washers on those hold down bolts shrink so the cover will not go down as far. Often the gasket is not the cause of the leak but these rubber washers are too thin.
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Where am I going and why am I in this hand basket?
_
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Brittles
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« Reply #7 on: January 31, 2011, 04:29:58 PM » |
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It's probably pretty important to tighten the valve cover bolts in a staggared sequence. An old mechanic friend, who I totally trust, told me to use a torque wrench on each sequence. Such as starting out with 5 ft/lbs and working up to the specified torque and doing it in 3 steps.
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John
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gammer
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« Reply #8 on: January 31, 2011, 06:06:19 PM » |
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Thats a good idea John. I know I've broken several of these valve cover bolts by hand tightening them. Lesson learned.
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leftfield6
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« Reply #9 on: January 31, 2011, 06:45:56 PM » |
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I replaced the bolt washers with new ones, so it can't be that they are too compressed. Is there a torque setting for these bolts? I don't remember seeing one in the manual. I didn't use a torque wrench, I used my "tight enough for aluminum" ballpark estimate. I have a highly calibrated elbow.  Okay, maybe not. |
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tomb raider
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« Reply #10 on: February 01, 2011, 04:36:38 AM » |
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I have a highly calibrated elbow HAHAHA !!!!! |
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Jimbo
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muttstang
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« Reply #11 on: February 01, 2011, 06:44:13 AM » |
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be sure to look up the timing thread ;) It is as good of a time as any to get some more low end grunt out of the 700! http://nighthawk-forums.com/index.php/topic,7174.0/highlight,timing.htmlInteresting as I'll be installing a new gasket on mine in the near future. Hoping to only do it once.
I know the manual doesn't say anything about it but should the gasket be "pre-treated" with motor oil before installation? Like is done on oil filters. I was hoping not to use any type of gasket sealant but I will if need be.
As far as reusing them goes.........the manual says to inspect and replace if neccessary.
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1985 CB700SC always a project in process! Cams re-timed ;)
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skramer360
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« Reply #12 on: February 01, 2011, 06:45:42 PM » |
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On page 1-6 of the service manual it gives general torque values for various sizes of bolts. I'd use that.
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I'd rather be riding my blue '85 (700s)
Steve
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spiritof86
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« Reply #13 on: February 02, 2011, 02:41:54 PM » |
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I used a little Super Gray gasket maker on the new gasket when I installed it and torqued everything to factory specs. Hasn't leaked at all since.
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I'm a Nighthawkus Emeritus
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