Topic: 77 CB750 missing condensation chamber; options?

[timmerk]

Hi all,

I have a 1977 CB750 that I'm trying to get running again, but noticed the condensation chamber is missing - just the top case with the 2 hose outlets is there. What are my options? I see the chamber is different on a 78, which is the closest one I found on eBay.

Thanks!

[lucky]

Just use the one from the 1978 model.
It is actually called a air/oil separator.
It takes fumes from the crankcase and when it condenses
the water goes to atmosphere and the oil in the fumes goes back to the crank case.

You could just use one from almost any motorcycle of equal size engines.
They all work the same.

[timmerk]

Ah, thanks! As you can tell, I'm a newbie. I'm trying to learn, though.

[martin99]

On mine I just have the hose from the cam cover open to atmosphere, behind the left-hand side panel. If you are missing the bottom part on yours, it's pretty much the same as I have anyway. Some put a small K&N type filter on the end, some fit one where it exits the cam cover. In my experience, it doesn't affect the running whatever you do. If you are into cleaner emissions though, you might want to try to source a new one.

[Bankerdanny]

Running without it shouldn't be a problem, it just vents vapours out of the crankcase.  But route the line carefully since you will get a fine mist of oil out of it and you don't want to get that on your tire.

You can add a small filter to the end to trap the oil, but you will likely get some dripping on the ground from that and will need to replace it periodically.

[Jerry Rxman Griffin aka MuthaF'er]

My F still has it's but I'm running CR31 Special carbs so no air box. That leaves me with one leftover hose from the seperator. I'm installing one of the K & N filters as mentioned. It will catch any condensate vs allowing it to drip somewhere unwanted plus it won't allow any thing to get inside.

[timmerk]

Any recommendation on a K&N filter? I'm guessing one of these crankcase vent filters would do nicely, especially since it has a vent tube for a hose: http://www.knfilters.com/vent.htm

[martin99]

Bling option...

http://www.ebay.co.uk/itm/crankcase-breather-pod-filters-filter-cafe-racer-cb750-cb650-cb550-cb900-cb700-/321395791369