Any pictures on how much gasket sealant to use on the cyclinder to crankcase?

[swanker]

No metal gaskets/shims on the 75 (?) + airheads and just some gasket sealant what the doctor ordered.
I'm not sure how much to put on, how thin to spread it out, do I put it on both the cylinder side and the crankcase or just one surface etc.
A picture would speak a shitload but there isn't much information out there on this.
Probably a noobie question but screw it, I'm a noob

[disston]

A 1975 has the gasket/shims between the cylinder base and the engine block.



Part # 11 11 1 255 001

A 1976 does not have a gasket/shim in stock form but there is one for use to make lower compression.

If your bike was built after September of '75 then you are riding a 1976 bike. Calling it by the year it was built is misleading. A 1975 model has a gasket/shim.

Post the serial number and we'll look up the build date and tell you what you have.

[swanker]

I've got a '78 R100 and understand it didn't come with a gasket (that's why I put 75+ didn't have them).
I'm not planning on using a gasket.
I am looking for direction on how best to apply the liquid gasket sealant.

[GSAviator]

Originally Posted by swanker

I've got a '78 R100 and understand it didn't come with a gasket (that's why I put 75+ didn't have them).
I'm not planning on using a gasket.
I am looking for direction on how best to apply the liquid gasket sealant.

http://www.bmwmotorcycletech.info/chemicalsetc.htm

[Airhead Wrangler]

As thin as effing possible. Use a stiff. short-bristled brush to to paint a film of hylomar/yamabond/hondabond/tribond onto the surface and let it set up a bit before torquing. It should be so thin that it's semi-transparent.

[usgser]

A "THIN" smear.

[supershaft]

On a professional basis I have had great luck with Durko spread as thinly as possible with a square bladed Exacto knife. One trick is to make sure the stud O-rings do not fall out of their recesses and down on to the stud before you get the cylinders all they way up on the case. I double check with a mirror right before they are all the way there. I put just a tiny dab of sealant on the O-ring to help it stay in place. If they fall down on the stud the rubber will deform the cylinder and/or case sealing surface and it causes leaks. I have seen a lot of engines that have had this ill fate. BEWARE and good luck!

[Stan_R80/7]

I highly recommend following the manufacturer's instructions on how to apply their product. Personally, I use Hylomar and apply a thin film to both surfaces. Here are Hylomar instructions: http://www.hylomar-usa.com/_resource..._Univ_Data.pdf


The last Hylomar I bought was Permatex Hylomar at Pep Boy's, they now sell Permatex Permashield gasket dressing & flange sealant as a comparable product: http://www.pepboys.com/product/details/9885956/

[squiffynimrod]

There is a pic of sealant thickness in this excellent tutorial

http://www.pbase.com/dqmohan/prtseals

[swanker]

Originally Posted by squiffynimrod

There is a pic of sealant thickness in this excellent tutorial

http://www.pbase.com/dqmohan/prtseals

Hell yeah.
Thanks all for the replies.

[jackd]

Originally Posted by swanker

Hell yeah.
Thanks all for the replies.

Well here's one guy that wouldn't use Hylomar on any surface that comes in contact with oil - that pic showing that blue crap spreading into the block area where the cylinder base flange lives horrifies me. And then I see that BMW sells the stuff over their parts counter. We only use that sealant to hold gaskets in position for installation on external air supply systems in my line of work - fixing airliners - we never let it near oil. In my early years wrenching there were service bulletins against using it for certain aircraft piston engines - when it got loose internally it tended to clog oil passage ways. I would go with the Permatex hi-temp product and probably spread it thinner than that and keep it back from the edges - it will spread toward the cylinder flange when you torque the cylinder.

[H96669]

Notwithstanding the Hylomar, that's a poor prep job. I see little bits of orange in the blue and some other stuff that shouldn't be there. Loctite 518 with the activator. Expensive for the best.

[blaine.hale]

I just used permatex RTV silicone on mine 2 nights ago. Just confirming what everyone said, I drew a small bead around the surfaces and rubbed it thing with my finger. I did tighten it down a little to squish out the excess then later torqued the head to spec. Worked on my last bike, should work just fine on this one.

[Airhead Wrangler]

Originally Posted by H96669

Loctite 518 with the activator. Expensive for the best.

Hmmmm. Never thought to use that on the cylinder base. I might give it a try next time. I like that stuff for getting rid of the enrichener gasket on Bings.

[jackd]

I tend to use a razor blade when I spread sealant on mating surfaces - you get a more consistent thickness than when you use your finger. Something I learned at work many years ago.