I thought I did a good job of cleaning and sealing my engine cases, but they are leaking before the first startup.
I used Loctite 574 to seal them, which cures in the absence of air and is typically used on air-cooled Porsche cases.
Thinking now that the cases don't fit tight enough for that sealant. It is designed for close fits, like .009" gaps.

Would I have any better luck with another sealant, or should I just get a larger drip pan?

terry

 

Be more specific.

Motor is fully assembled and you put oil in the crank? Motor in frame and oil in the tank?

Sumping is a big thing with them, some can be mitigated but sitting for a long time they will sump.

Or can you actually see a leak from your cases?

Pics are everything.

 

Good questions - I should have given more detail.
Unfortunately, it is just sitting on the stand with no connection to the oil tank, so no outside pressure.
I added about 4 ounces as I put the cam gear cover on.
It is leaking on the bottom of the case halves where they join.
I can wipe it dry at night and a new drop will be there in the morning.

If this is not 'normal', I should probably crack it open and try another sealant.
As I mentioned earlier, I probably need a sealant that will accommodate a larger gap between the case halves.
It certainly won't get any better when there is crankcase pressure.
What is a better sealant?

t

 

If its leaking from the joint then you need to reseal it unfortunately and be happy you discovered the leak now and not when the bike is together and running!

 

Yeah, I agree it has to be fixed.
- I need a different sealant
- This flywheel assy is new to the case and I may have to adjust the thrust washers to get it centered.
I have the right crank end play, but I am waiting on the pistons and cylinders to be delivered, so that I can make sure that the flywheel/rods are correctly centered in the case. If I need to center the flywheel, then the gear cover has to come off again.
Always something!

t

 

i use ( Yama bond 4 for ) case halfs and threaded plugs been good to us 30 years - you can pull the one side and re seal and re assemble

you might want to epoxy the trans studs tops - as they leak through the threads and the slots that align with the frame - 1/2 turn to tighten them is a lot - so we epoxy the tops - then use glyptol to coat the inside of the case - I have also drilled and tapped a 1/8 pipe plug in the trans case you can get to so you can drain and re fill the gear box < just a thought we have an evac pump not every one has one

the block looks sweet BTW

 

YamaBond 4 !
Thanks John. I used it before and forgot how good it was.
If I don't have to shift the flywheel to line the rods up it will be easy.
As I mention above, the bottom end came from a different case, so I'm not sure if the flywheel/rods will be centered in the case.
Truett&Osborne rebuilt the bottom end and they still have my cylinders. I'm looking for a procedure to measure to ensure the rods will be centered.
I like your idea of sealing the mounting studs. I'll do that.
I have a suction device for the tranny fluid, so i'll skip drilling/tapping the case.
I am adding a magnet inside the tranny case to collect all the teeth I break.
Found one at McMaster-Carr that fits on the reverse gear shaft.

 

we JB weld that sort of thing but leave it a bit thick don't press it to the case

remember the JB weld desplay bottles they were always thick holding stuff

 

I have a magnetized drain plug in the transmission cover, you can not see it unless you get down on the ground. To drain the fluid you just need to pull the plug lean the bike over, takes a minute or two and away you go.

Funny, I noticed a transmission leak my last ride, I think the studs, which I know I sealed, are leaking. need to get underneath her to check. But it was only a drop or two, that is Winter work. For now I will just top her off before I ride.

Keep going, looking good.

 

Where did you guys drill the drain hole?
Pictures?