Blew a gasket..Literally! lol

[slyone]

Kinda a 2 parter problem maybe? I just finished valve adj w/new cam plugs, run great except idle return sucks, doesn't seem mechanical..at least not entirely? anyways went on a 5 mile rocket run, then idling 5-10 minutes, then end plug just let loose and spewing oil..WTF! now I see the reason people flip em'..upon closer examination I see the plug had no sealer(HondaBond 4) between top surface and cam gasket, not sure if it should have? Is this failure caused by excessive backpressure? and if so, could it also have something to do with my slow rpm return to base? I mean really, it sounded like I was speed shifting thru the gears and cruise control when cruising along not a good way to be operating a roadbike. I'm just kinda bummin...got my tach cable out and resealed but tach response is on serious drugs too

[koolaid_kid]

First, I would not use Hondabond or Yamabond or 3m bond (same thing) They do not dry, by design. Use RTV, it is cheaper and will dry. Second, yes, reverse so they don't blow out. Third, find out why the pressure is not escaping through the factory vent hose(s).

[slyone]

First, I would not use Hondabond or Yamabond or 3m bond (same thing) They do not dry, by design. Use RTV, it is cheaper and will dry. Second, yes, reverse so they don't blow out. Third, find out why the pressure is not escaping through the factory vent hose(s).

lol It seemed the general concensus around here was to use the 3m bond and the HBond sounds exactly like it...didn't want to mess up it seems to be dry? Upon reseal, I'll run a light coat on top to mate with gasket too...? I'll reverse them..can I use them over again since they're brand new??
3rd, guess I should check where hose goes into air box..? This sucks

[loud et]

Clean those moons up and yes you can reuse them. It is usually said to only put sealant on the curved portion of the plug, not on the top as it will stick to your valve cover gasket. Oil or wd 40 your valve cover gasket and you will be able to reuse it when you do a valve adjsutment. If you use the sealant on the top of the moon, it will stick to the gasket and tear it when you go to remove the gasket.
I used black rtv. I put my moons in flange in. I let the rtv dry overnight after torquing the valve cover back on.

[Nessism]

Did you wait for the sealer to harden before starting the engine?

Threebond 1194 is what I use.

[slyone]

Did you wait for the sealer to harden before starting the engine?
Threebond 1194 is what I use.

Yes about 36 hrs. or so. Seems odd that after warmup and a 5 mile ride, then idling about 8-10 minutes it pushes out? Is there more upper end back pressure at idle?
Also, I did not have the engine racing or not returning to base idle on deacceleration before the carb overhaul/valve adjustment procedures..
maybe like a "vacuum leak" on a car but once down, it idled very nice

[slyone]

Breather cover and hose were both clear of any obstruction and I just pulled the air cleaner and all looks good, I will however blow air thru breather nipple at ait box...hopefully tomorrow!

[chuck hahn]

I ..as well as many many others..use Three Bond 1194 without any mishaps. Just a thin coat is needed. Let it set up for a good 1/2 hr and that should be sufficient for assembly. Little tip here is to have a little piece of steel or whatever with a flat edge to se them in the recess. Line them up and use the flat edge to be sure they are level across the edges of the machined head surface. You dont want them cocked up at one end if its avoidable. AND over torqueing the cover bolts will start the pushing out process too. Use a inch torque wrench at the specified torque ( 10 inch pounds if i recall right). If you dont have a torque wrench then use this method..Hold the wrench with the tip of your middle finger against it once you get the bolt to start feeling tight. Then just use that one finger and push the wrench till it stops turning the bolt. Believe it or not, this actually gets them pretty darn close to right!!!


EDIT...Be sure to degrease all mating surfaces WELL with rubbing alcohol or some laquer thinner.

[slyone]

yea I know, I always wipe surface to be sealed/gasketed with an alcohol based product to remove any residue, I torqued camcover too. now I got this new tube of hondabond and everyone says rtv..wtf? now my $50.00 cam cover gasket which I installed dry will prolly leak on reuse due to gasket compression? and everyone says to "grease gasket" that's a new one on me?

As you can see, 2 others are ready to pop too? though when 1st installed they did not set as flush to side as I would have expected? so much for HB, I'll be trying "something else" upon reseal! and..maybe I should turn em' around??

[koolaid_kid]

There are several types of Hondabond and 3Bond. You want the one that dries; some do not.
The gaskets are reuseable. While they are designed to go on dry (no sealant) some grease them lightly so they do not adhere to the surface and tear.

[tkent02]

Regardless of how you put them in, they shouldn't fall out. Something is wrong if you have that much pressure inside the engine.

[koolaid_kid]

We were in Robbinsville for the rally one year when firsttimer blew out a plug on his Yoshi replica. It was ugly.

Like I said, it does not look like the sealant he is using is the drying kind, and his crankcase pressure is way, way too high. I suspect it is a combination of the two that is doing it.

[slyone]

Like I said, it does not look like the sealant he is using is the drying kind, and his crankcase pressure is way, way too high. I suspect it is a combination of the two that is doing it.

I'm not using the Hondabond anymore, it says semi-drying..? Not sure about excessive backpressure, I think you're right on the sealer and the seal just walked. I was thinking I'll install reversed and will clean out air box tomorrow too.

[koolaid_kid]

Like I said, they make several flavors. I used Yamabond (same stuff) on my case halves when I put the GPz together, and your pics looked exactly like what I used, which was the stuff that did not dry. That is why they slipped out. At least I got half your problems correctly diagnosed.
AFA backpressure, is it possible to leave the hose disconnected from the airbox so you can do the old "hand over the hose" to check the pressure? There may be a little, which is why that hose vents into the air box, but not an excessive amount (subjective, at best).

[chuck hahn]

Well you wont like the fact that Three Bond says the same thing. I would be sure the breather meshes arent all pluigged up too. Whatb airbox setup are we talking about?? If stock, is the hose running to the nipple on the airbox? Seems to me that the excessive pressure is coming from the valves not seating fully and your basically blowing the top- end full of compression. I know you adjusted the valves...but thay may be worth a second look. Roll each lobe around so it is pointing directly AWAY from the bucket and then see if the bucket is moving around freely by trying to move it with your finger. If they dont at least all move freely by finger, then the ones that dont you need to see whats up with those ones, because they are holding the valves open.