Forum

[Graham43]

In order to keep the garage floor clean (and my friends drives) I bought an ali water bottle from the pound shop and fitted it as a catch tank for the main breather coming out of the top of the gearbox/engine on my Electra X - I was very surprised how quickly it filled up. Full of creamy oil. Is this 'normal'? I note that Hitchcocks sell a breather kit that returns the oil to the filler cap, not available for the Electra X but I am sure I could make one - is this a good idea? Looking forward to the usual knowledgeable and helpful comments. Thank you.

[Frank]

The engine doesn't get hot enough to burn off the condensation so it is normal that you get a fair amount of emulsified oil blown out the main breather. That is better than having it recirculated through the engine as per the original set up. I kept the original catch can which was mounted high enough to minimise oil loss, I just disconnected all the other outlet pipes breaking the recirculation cycle and routed the can outlets to the vent to the outside. There is now only a spot or two of oil dripping from them after a long run and no more blocked pipes.

[Davie Hall]

Can you tell me/show where this can is mounted? . I sometimes wonder if the condensation in the oil contributed to the big end failure on my bike.

[Leon Novello]

As Frank says, the engine doesn`t get hot enough. They run too cool.
The oil should be around 80c; it only gets to around 50c, maybe 60C on a hot day in Australia. You can fit an oil temperature gauge to the indicator stalk with the probe through the oil reservoir drain plug if you are interested in watching it.

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[Frank]

Davie, the original can was mounted next to the top right hand side of the battery, bolted to a frame tube under the seat. The advantage it has is that it contains a duckbill valve so that to some extent it just blows out and doesn't suck back in. I've also fitted a replacement hose to the timing case which contains a one way valve so that it sucks fresh air in only, so that it can ventilate the system.The hose to the airbox has been removed and the hole in the airbox blanked. The spare ports on the can have been routed down near the battery breather hose. I was surprised at the amount of visible water vapour blown out initially but it soon settled down and all I get now is a couple of drips from the drain hose after a good run. Crucially the pipes never block, previously I would be cleaning them out every 300 miles at least.

[PeteF]

The breather pipe needs to be routed upwards first so oil tends to fall back and just the vapour escapes. Up behind the battery seems to work for me. It does need some sort of one way valve as well; the simple duckbill does the job.
You don't want that crap back in your engine (well I don't anyway) I suspect that commercial breather systems are not allowed to dump any oil overboard.
When I got rid of the original catch can I monitored what was coming out of the breather and found it was so little that I didn't need to catch it.

[ed.lazda]

The water vapour has to come from somewhere. The breather system can, but shouldn't, let air into the crankcase on the upstroke. Another source -- maybe the main one -- is from exhaust gases getting past the piston rings. Maybe these need to be checked.

I used to get a lot of "mayonnaise". Mucking around with the breather system seemed to make a bit, but not a lot of difference. Then I had to investigate some piston slap, which ended up with a new barrel and piston. Now, no more mayonnaise.

[wilf]

I got rid of the catch tank on my 05 bullet after being unable to stop oil emptying into the air filter box. I mean ALL of the oil! For a couple of years I had both pipes diverted over the chain, which was a bit messy, but oil consumption was only very little. Recently I decided to do a "proper" job and ran the crankcase breather up and back to exit behind the back wheel. Very little mayonnaise seems to escape, but I have big trouble with the smaller pipe from the back of the timing case which seems to be constantly pumping oil out. I have a short piece of pipe jubilee clipped to the outlet with a bolt inserted into the end and again jubilee clipped. Oil still gets through. Would a duck bill in the end of the crankcase breather pipe cure this?

[Graham43]

Thank you for all this information. My catch tank was fixed down by the footrest so now I see I was causing more problems so I will fit it high up. I have a breather filter to feed fresh air. I agree with Frank, I don't fancy recycling this fluid back into the engine. Thank you all.

[Frank]

Wilf, I'm not sure that trying to block the timing chest pipe off is a good idea. Ideally it needs to suck fresh air in. I ordered a new pipe from our hosts which came with an internal valve so it allows only a flow of air into the case and nothing the other way. The main breather pipe has a duckbill, in my case in the original catch can, so that it can only breath out and not suck in. Ideally the air going in to the timing case needs to be filtered so you could route it to the airbox where the disconnected pipe from the catch can used to be.