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cylinder base gasket - gasket sealant?

mnvkngs65

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Finishing the upper motor rebuild on my 73 cb750 and am a little nervous about the final steps failing (i.e. gasket leaks).

I have a KP gasket set and was wondering if I should use any type of gasket sealant on the cylinder base gasket? The online company I bought it from advertised it does not need it so I'm inclined not to.

Also, I purchased new APE cylinder studs and plan to torque them down to their recommended ft/lbs and then loosen them and retorque as many suggest.

Do I need new nuts for the studs or can I use the old ones?

Thanks for any help.
 
if the surfaces of the block and cylinder are clean with no nicks you shouldnt need any sealant. I tend to use Copper kote on the gaskets and have had no issues. Dont use silicone or RTV anywhere on these motors. Hondabond or equivalent or Copper Kote on certain gaskets. Pay attention to the head gasket material and quality. I only suggest using the graphite type material head gaskets. Many of the aftermarket head gaskets are a cheap hard gasket material, I have used them and they all leak at some point no matter what you do to them. For stock rebuilds I only suggest OEM honda or Cometic graphite head gasket.

You can use the original cylinder nuts no problem with the APE studs.
 
Hi all, I'm about to reassemble my engine and I nicked up the base gasket surface. Should I use sealant in my specific case? I have some Hondabond but I was told its only for metal to metal surfaces? I also have the right stuff which I was told not to use with gaskets. Should get some gasgacinch or something else? I should mention I bought the full Vesrah gasket set so that's what I'm working with. Thanks!

https://drive.google.com/file/d/1qvBdEuST78H_U0tnQnmbBFlNZdI1tLlH/view?usp=sharing

This is the worst of it:

https://drive.google.com/file/d/1ZY2EYZc3Tf1mxTIrEfrvo0JlthfbN3hm/view?usp=sharing
 
Need to have understanding of what kills you there at your localized damage area. The high spots. The lows aren't spit, the gasket simply crushes into those to hold better as long as the lows do not lead from inside to outside to form a trough to leak oil. Out in the middle of the flat lows simply become trapped air pockets that do nothing. It's the highs that screw up gasket by holding the 2 metal parts apart to leak.

With that in mind, take a small flat file (ignition points file works perfect) like Harbor Freight sells in a pack of different type 5 inch files for small $$$, and LIGHTLY move across the damage while lightly pressing file down to stay in flat using the surrounding metal as support. In 2-3 short strokes you will be able to tell where your highs are as compared to lows which will not remove any metal at all. Lightly work the highs down until you are close to matching the surrounding metal, it shouldn't take virtually any work there at all. You may even find there are no highs at all. Come back and dress the worked roughness lightly with say 400-600 sandpaper to meld the work into the surrounding area, the idea being removing as little as possible. Remember if you have damage on one part the opposing one likely has it too if it came from prying parts apart. Those spots might take a minute total to dress and then put your choice of gasket sealer (Hondabond works fine) in the lows only. You don't want to put sealer over the full gasket as the more sealer you add the more the gasket can squeeze/squelch out of place in distortion to leak. You want as much of it dry as possible to lend friction to holding it in place. Make sure you do use all the rubber seal o-rings on cylinder spigots as well as for sure the back row inner 4 cylinder studs which can leak on some engines. Don't forget your dowel pins.

I have assumed this is on an early DOHC based on your past postings.
 
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You might want to try diamond files. It's one of the tools the Chinese haven't been able to screw up yet. They are quite small and easy to work into tight areas, and even the coarser ones remove material very slowly. I use them for gunsmithing, and couldn't live without them now. I'll mark the area with a sharpie to reveal the high spots and know precisely when material is being removed.
 
I've thought about them but always concerned the diamond particles might not all be the same size (height) to alter the true dead flat of the file. The bonding process thickness worries me too. If Chinese made, I already avoid cheap value Chinese sandpaper as it mixes different size particles to sand weird patterns. Their listed #500 I feel has both 400 and 600 grit particles in it, it sands well but does not leave as smooth a finish.

Maybe nothing, I haven't used them in a big way.
 
That'll work, use # 5 or 6, be careful, one looks flat but is slightly curved, you want the flat one. Mine came in a red plastic slip container and no handles like that. One piece each file.
 
I've thought about them but always concerned the diamond particles might not all be the same size (height) to alter the true dead flat of the file. The bonding process thickness worries me too. If Chinese made, I already avoid cheap value Chinese sandpaper as it mixes different size particles to sand weird patterns. Their listed #500 I feel has both 400 and 600 grit particles in it, it sands well but does not leave as smooth a finish.

Maybe nothing, I haven't used them in a big way.

I've been using the diamond files on gun actions for years with no issues. They leave an exceptionally flat and smooth surface, which is what we want for a crisp trigger job.
 
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