Cam Rubber End Plugs

What sealant should I use on the half moon end plugs? Mine started leaking in about a year. I used a small amount of Ultra Black RTV. I think they are aftermarket plugs but they seemed to seal nicely when installed. I  just ordered OEM plugs hoping they will work better. 

Thanks
Len
1982 LTD 750
1981 CB900 F

There should be no issues with either stock or aftermarket half moons if sealed correctly with RTV.
I use VTECH Vital black 600 degree RTV.
I set them level in the head with a straight edge/steel rule and leave overnight to cure before fitting the gasket and cam cover.
Just before fitting the gasket peel off any excess RTV from the inside and apply a light smear of RTV across the top of the end plug making sure it overlaps the joints either side.
Once the cover is bolted down peel off any excess RTV from the outside and you are done.
 

I’ve always used Yamabond4.  It’s a semi-drying liquid gasket sealer.  A thin skim coat is all it takes, no need to gloop it on.  I RARELY use anything else on engines.   

a.co/d/03bhX7Sn

Later, Doug

I've used Yamahabond#4 forever but same as Hondabond equivalent. Like as mentioned, don't be in a rush! Half moons installed with product, install cam cover, clamp down and let the bonding agent cure overnight. Beware, a lot of those aftermarket moons like to slip out under pressure. Crap that Z1 enterprises sells will do that to you, just not the same as original. This is thru personal experience.  

I've had good success with the aftermarket machined aluminum cam end plugs I got them from Blue Moon on ebay, but there are other sources also. I think Z1parts.net also sells them, their stuff is high quality. Same as previously stated, THIN coat at head install plugs flush with a straightedge for checking. Let cure and then THIN coating where cover meets plug and install cover. Never had a leak this way.

 That's all I do now is the machined half moon plugs from  Blue Moon on ebay. I also order drain plugs and the carb tees. He makes good products. You need to check the fit of each plug first because sometimes you need to file the end of one or two of the castings down a bit. some castings are just a bit wider than the machined plug. I use Yamabond/Hondabond to seal them. 

Yamabond #4, and after they start leaking get rid of them. Once they leak you can add 100x different sealer, and 100x they will leak.

Cra-z1 wrote:

 That's all I do now is the machined half moon plugs from  Blue Moon on ebay. I also order drain plugs and the carb tees. He makes good products. You need to check the fit of each plug first because sometimes you need to file the end of one or two of the castings down a bit. some castings are just a bit wider than the machined plug. I use Yamabond/Hondabond to seal them. 


 

    ^^^ Exactly that ^^^

   Not unlike some firearms mods wherein the vendor states, "Some fitting may be necessary." 

   We bought some sets of the light blue APE plugs decades ago that required light fitting of a very few of the bored half-moon ends in the head to seat fully.  A couple / three strokes with a points file.  Or, just trim a tiny burr parallel on the inside  with a thin, sharp blade.   Once fitted correctly & sealed, they're very unlikely to weep in the bored half-moon cutouts.

Good Ridin'
slmjim & Z1BEBE