During the last ride we blew a belt on the death machine, busted the left rear shock eye and then I noticed a collapsed bellows. I'm suspecting that the crank seal on this Engine is on the way out. This is the Engine with the welded piston and the Engine that blew up the clutch on the homemade dyno.
This machine and Engine have seen a lot of action.
The good part seems to be that it's not pulling oil out of the counter balancer area and the oil is clean.
The clean oil means that the seal is not allowing two stroke oil into that area from the crank case.
The collapsed bellows does tell me that it's pulling a vacuum. What puzzles me is that there is no oil missing.
CO

Does that when it's running? Or does it do that after cooling of, after running?

If it's a sealed up system I would say that's a good thing. Expansion and contraction! Now if it never did that before maybe not. I would think like any vehicle it has to take place to operate properly. Any Engine,trans,diff etc.

You did say the weather is changing, may be barometric pressure related and its effects on the fluid in a confined space with a quantity of air. Check the pressures for the past week and see.

Would would be cool if this set up can detect a seal going out. Discovery by accident.

With that broken shock eye. Get ya at least one bearing for miss alignment and run you a radius rod on that will help take load off of shock eye. With your hacking skills should be easy.

What I like is the fact the welded piston is still working.

And so is the homemade head .
CO

I might believe your theories above but that does not happen on my other two machines.
CO

I didn't notice until we got home so I can't say for sure when it happened.
CO

One thing that I do know for sure is that if you check your counter balancer oil and it's black then you know the crank seal is leaking and allowing two stroke oil from the crank case into the counter balancer area. I have commented on this in the past.
So that's a quick and easy check.
CO

Vented any way. One way check valve?

My first thought was it just happened because it cooled off. If the system is sealed, but vents with enough pressure, wouldn't it make sense that the bellows would look like that after it cooled?

Well if the system is sealed then how did it vent ??
Not sure what is going on here but my other two machines don't do this.
Might have to keep a closer eye on my other machines and this one to be sure.

At the end of the day this machine runs fine, even though it's the experimental unit. It has been through a lot ---- A huge crash that broke my back and twisted the frame -- Many very high speed runs up the mountains when I first got them -- A huge clutch explosion on my homemade dyno -- Experimental head -- Welded piston -- anything else I can dream up.
CO

I used the word ''sealed'' loosely. Even if the system were only able hold a percentage of a psi before it leaks at, lets say where the hose goes into the bellows, then as the system cools, you get a small amount of vacuum.

Kind of like when a plastic gas can swells up, some of the pressure then slowly leaks out through the threads in the cap, or the vent cap, then as the can cools, it looks like it's caving in.

Flux capacitor????