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By Allanfox
#91205
Hi, while i have the bike in bits I am just having a chassis tidy up and was giving some thought to removing the huge plastic airbox and moving the catch pot across a bit, all very tight under the seat!

Not planning on changing the carb at the moment, is there a suitable K&N type filter that would fit directly onto the back of the UCAL CV BS 29 carb, not a lot of area to clamp to, anyone done this? I assume the CV carb would be ok with this?

One logic is every time I open the airbox there is a pool of emulsified oil in it, can't be good to the longevity of the filter, with a catchpot move will be able to vent elsewhere and not make the bile eat its own exhaust!!

Or more trouble than it's worth?
TIA
User avatar
By Allanfox
#91215
Hi Tony, not don't think it is that, they just breath into the airbox and sure overtime the fumes will condensate into gloop, just doesn't feel right to me that we put filters in the same place as the oily breathing goes. Just starting to put it all back together as have been waiting for local engineers to reopen as need as few bits of work doing.

Now I know the sump and oil-tank were joined by the crankcase leak it does explain all the history of wet sumping, disappearing oil and and oil coming out of breathers, just hope it has fixed it!
By papasmurf
#91216
Allanfox wrote:
Thu Jul 02, 2020 7:10 pm
Hi Tony, not don't think it is that, they just breath into the airbox and sure overtime the fumes will condensate into gloop, just doesn't feel right to me that we put filters in the same place as the oily breathing goes. Just starting to put it all back together as have been waiting for local engineers to reopen as need as few bits of work doing.

Now I know the sump and oil-tank were joined by the crankcase leak it does explain all the history of wet sumping, disappearing oil and and oil coming out of breathers, just hope it has fixed it!
If oil is getting into the air filter box, it is too much oil. (You have followed the precise instructions for checking the oil level?)
User avatar
By Adrian
#91217
Here's the UK site for K&N universal air filters, there must be one among the five pages worth that will fit on the carb and under the side panel, which I presume you want to keep! Clue, use a narrow band jubilee clip. Ramair also supply some universal pod filters, have a look for those too. The other option is a direct K&N replacement filter for the Indian OEM item in the filter box, there IS one but I can't remember the number.

https://www.knfilters.co.uk/air-filters/universal.html

While you're working on the bike, I suggest this if I haven't already done so (my memory is cr*p these days) : ditch the entire catch can assembly, it can clog up resulting in oil being pumped up out of the timing chest and overflowing the catch can into the air filter housing, which sounds like is what has happened with yours.

Block off the smaller bore hoses to the back of the timing chest and the primary drive.

From the original collection of 1/2" breather hoses keep a short piece from the hose with the 90° bend in it. Fit that on top of the breather pipe exit from the oil tank, plug a non-return valve into it (not one with too strong a spring ), then run a longer piece of hose from the NRV along the rear chain guard to the back of the bike.

Sorted.

Just remember not to overfill the oil tank, as papasmurf says. You might get a little emulsified residue dribbling from the breather pipe end, but if you can keep the rear pipe run straight that's about it.

A.
User avatar
By Allanfox
#91219
Now, I am liking your thinking and does make perfect sense, Papa-smurf is correct of course and I have been very careful with oil levels but I do think there is an inherent problem with the standard set up anyway. What I don't understand is the timing case breather has a duck bill on the inside so surely it is intended to breath into the timing chest, I thought duck bills were on the end of a pipe like a NRV? I have no idea what the primary breather does , there is a crank oil seal so what pressure is it relieving? Is it all just part of the clean air aspect of the leanburn, no fumes will escape unfiltered!!! I was thinking of clipping the pipe to the back mudguard using 'P' clips a bit like my old Bonnie had. But hadn't thought of the chaingaurd!!
User avatar
By Wheaters
#91220
I’ve gradually come to the conclusion that the oil return to the reservoir benefits from the timing case being slightly pressurised. This would explain why the duckbill fitted to the timing case breather fitted to some bikes was on the inside.

My 350 has only one engine breather and that’s the one on top of the oil reservoir and that’s how it came from the factory. I also recently discarded the catch can and fitted a one way valve in the breather. The breather pipe now vents onto the lower run of the rear chain. Excess blow-by oil (not that there’s any to speak of) just lubricates that. It seems to work very well. Before, the catch can used to block with gunk quite often and when it needed cleaning out the exhaust began to smoke. There doesn’t seem to be any exhaust smoke now.
User avatar
By Adrian
#91225
The duck bill on the inside of the timing chest is SUPPOSED to act as a non-return valve on the Electra-X (I'm not familiar with the 350 Electra's set-up, it might be slightly different), but it's pretty useless!

What can happen (and did on mine) is this. The main breather pipe between the top of the oil tank can get blocked with oily gloop/condensate/mayonnaise if it doesn't have a constant rise. With the main breather blocked, crankcase pressure will still be looking for another escape route. This will now build up in the timing chest via the oil tank, and from there force its way past the duckbill, which might as well not be there, taking oil from the timing chest with it, which it dumps in the catch can. This oil fills the catch can and then overflows through the catch can's gas vent pipe up into the air filter housing. Yuk.

A.
By papasmurf
#91227
Allanfox wrote:
Thu Jul 02, 2020 7:10 pm
Hi Tony, not don't think it is that, they just breath into the airbox and sure overtime the fumes will condensate into gloop, just doesn't feel right to me that we put filters in the same place as the oily breathing goes. Just starting to put it all back together as have been waiting for local engineers to reopen as need as few bits of work doing.

Now I know the sump and oil-tank were joined by the crankcase leak it does explain all the history of wet sumping, disappearing oil and and oil coming out of breathers, just hope it has fixed it!
You do realise there is a ducks bill in the catch catch can?
User avatar
By PeteF
#91228
There seems to be a lot of confusion about the crankcase breathers fitted to the later RE classic Bullets (after about 2004)
The later Bullet (Iron barrel) models do it like this;
1. There is a hole in the wall between the crankcase and the oil tank so that pressure from the crankcase passes to the oil tank (this is not really an oil tank as such, but the rear part of the main engine casing which is a separate chamber to the crankcase)
2. There is a vent out of the top of the oil tank, which relieves pressure via a black rubber hose into the catch can, which is situated behind the battery.
3. Pressure is vented to the catch can through a duckbill (non return valve) which is inside the catch can.
4. Excess pressure in the catch can is vented through another tube to the air filter in the RH toolbox.
5. Oil (and water) caught in the catch can is returned to the engine via another tube to the back of the timing chest. There is another NRV in this tube so that oil can't blow up from the timing chest into the catch can. (I suspect that oil drains down to the timing side mainly when the engine is stopped) Some people think this is a timing side breather but it's not.

IMHO the best thing to do is ditch the whole system and fit a length of 1/2" ID plastic tubing to the vent in top of the oil tank
Lead the pipe up behind the battery to terminate under the LHS rear footrest and fit a duckbill in the end. (you can take the one out of the catch can or get a new one) You need to block off the return pipe to the timing chest as well.

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