Why don't more of us put adhesive on the 'upper' case half?
 

When you read/talk about 911 bottom end assembly, you always see the 574/yamabond/1104/whatever going on the 'stud side' of the case. That is, the case half attached to the stand.

Why is that?

Last night I did a bottom end. For *****s and giggles I put the adhesive (Threebond 1104) on the upper case half. Not only was I able to apply the adhesive much faster when I didn't have to navigate around all those studs, I was able to get a much more consistent rollout. So, why isn't everyone doing it this way? What am I missing? Sorry, just idle curiosity on a Friday afternoon....

You might get adhesive on the threads the way you did it? :)

I thought everybody put the sealant on the side without the studs. It makes it much easier.

-Andy

Steve - I think you mis-read. I put the sealant on the side w/o the studs.

Andy - yeah. I think I'm sold. Tonight I had to re-do the case b/c of a tweaked oil pump seal, and did the sealant on the top again. MAN it is easier - even the cleanup from the first round was better. There wasn't sealant 'squirted' up all the studs, there was less squeezeout because I was able to apply it more sparingly.

Makes sence to me other then you run the danger of the sealer being scrapped off by the studs if the top side is not lowered directly into the holes......result -no sealant = leak.....

Other issue is that sealant from the holes ends up on the threads of the stud as it passes through the hole....no big deal you could just wipe it off!

Mark......

What is the general consensus on the best product for this, Yamabond, 574, etc.? I'll defer to Wayne's book but wondered if there was any late breaking news on the best product...or is this one of those subjects that generates heated discussions and name calling?

Mark - lowering directly onto the studs is easy enough, and you can also check the mating surface before lowering down all the way. Any errors can be touched up. This really hasn't been an issue on either of the times I've tried it. As far as sealant on the studs as it goes through the hole - not sure what you mean here. No sealant goes in the holes. You're laying it on too aggressively if there is.

Buck - please see one of the many other threads on case sealants. There is no consensus. I'd rather this thread not degenerate into another my-goop-is-better-than-your-goop threads. Incorrect application and bad prep seem to the culprits in most failures.

dtw,

It makes sence to me to put on the upper ...just trying to justify a practice that has been around for years with no apparent reason...also trying to justify why I did not think of it!

Have used this method on bikes for years.....everyone in Porch land says lower BHA BHA...just following the other sheep.

Mark...

The factory tells you to put the sealant on the LEFT case half, the one without the studs poking up. This way you can use a roller to apply it and get a smooth, THIN (nearly invisible) coat.

That's the way I do mine...

I also did the left side. I used Threebond 1194 because 1104 is no longer available. Spent a day on the dyno and now back on the bench. No leaks so far.