1980 Invader 440 head bolt torque, sequence & a couple other questions

[freak_in_cage]

This started as a crank seals job, but once I had the motor out I decided to pull it apart and give it a quick "go thru". Everything seems to be good and also to my surprise, it looks like this motor has been tore into at some point in the past. The crank seal on the PTO side was a weird 2 piece one that still looked to be in decent shape, but the MAG side was absolutely sucking air. Although the seal looked good, where it sat in the crank case had a fair bit of corrosion that had to be gently scraped out.

I have read doing the seals three ways. One way is to just put the seals in the case. The second way was to apply Yamabond to the case where the seal sits. The third way was to just put the seals in the case and apply Yamabond to the outside. It seems that the second way would be the best except for the possibility of plugging the case vents. What are the opinions on this? Since I'm asking about seals, some things say to just oil them to get them on the crank and other things say to grease them, which is right or is it personal preference?

Now it's time to reassemble and I cant find the head bolt torque sequence or specs. The only thing I see in my service manual is for the LTD head that goes over both jugs.

I am also thinking it might be a good idea to add another washer or two to the studs to accommodate for stretched studs. Would regular grade 5, zinc coated ones I get from the hardware store be adequate or should I go harder?

The last question is about using sealers on the gaskets. When I tore the engine down, every paper gasket had high temp silicone gasket applied to both sides (including the head gasket) and every seal that had an o-ring type seal had Yamabond applied to it. Would you guys agree it would be prudent for me to do the same thing? If yes, what is the best way to get the o-rings cleaned without damaging them?

Thanks in advance, all the info I get from this site is priceless.

[gixxer6]

My recommendations:

-Lightly oil the surface where the seals meet the cases.  This prevents the corrosion that happens. 

-Grease the insides lip of the seals. 

-grade 5 washers are fine.  Or replace the acorn nuts with regular nuts.  I like the look of the acorns, so I use stainless washers under the original washers.

-most gaskets do not need sealant.  With the exception of the exhaust gaskets and possibly the head gaskets depending on what kind you use...

-If the orings are perfect, no sealant is needed.  If they're damaged/old, use a little sealant

[freak_in_cage]

Excellent info, Thanks! What about torque specs and sequence?

[rminier]

 The shop manual says to torque the head bolts to 16 ft. lbs., using a crisscross pattern. Take them to that final torque setting in 1/3 increments.
  Don't forget to install and torque down that front coolant manifold to the cylinders, so that they are "square" and aligned, before you torque down the cylinder head bolts.
 And, it is good idea to re-check the torque of the head bolts after you have run the engine through a heat cycle or 2.

[Lloyd (ljm)]

 I would agree.

 Although I do give a very light coat of Yamaha bond between the cases and the seal. Oil should work just fine, But I have the Yamaha bond out already. I two grease the insides of the seal, Probably over grease them, but what will it hurt??

I rarely get Winderosa head gaskets to seal. The rest of the gasket kits are fine. Just head gaskets haven't worked very well for me.
Any washer under the acorn nuts will be fine. They don't get torqued that hard. I often use regular nuts, depends how pretty I want the engine.
 That funny two part seal works very well. Remember they seal both directions, Both the gearcase and the crankcase. The PTO seals are the ones that usually last the longest, Oil the gearcase side keeps them lubed.

 If your using a Winderosa head gasket. I would be tempted to give it a very thin skimming of Yamaha bond. The rest of the gaskets either dry or a very thin skin of either Yamaha bond or RTV sealent.

Hope this helps some

[freak_in_cage]

Thanks for the info guys. I am using the Winderosa gasket set. I have heard of them not sealing the best. I hadn't thought of using the Yamabond on it...I really didnt know if it would work. I also have Permatex copper that I use on the go kart and mini bike heads but if the Yamabond will work for everything, then I don't have to open a new tube of copper.

[gixxer6]

I always recommend to everyone that they use the 2 piece OEM 4/6 LTD head gaskets.  They never leak, are re-usable, and do not require any sealant.  They are a little harder to find, and will probably cost a little more than other head gaskets, but IMO they are worth it.  I've tried just about every kind of head gasket made for an Invader, and have had all leak except the 4/6 gaskets.