Engine breather B31

[DGBland]

When the engine is running should I be able to feel some sort of pulse or air coming out the breather pipe.?
The valve in the breather pipe connection appears to be working fine. I have a new oil pump returning oil properly and have put new oil seals in the timing cover.
I can't feel any air coming out the breather pipe at all. I have also fitted a new spring and ball in the return valve. I read somewhere that these springs can occasionally be a bit too strong and I was wondering if this would prevent the oil flow into the timing case?
Thanks
David

[Roy]

You would normally feel the engine breathing yes ,if you take out the valve and start bike with out it in you would /Should hear it breathing ,and if oil is getting around timing gears etc you would get oil/vapour come out of breather hole , obviously put valve back in when riding bike

[Bigsingle]

You would normally feel the engine breathing yes ,if you take out the valve and start bike with out it in you would /Should hear it breathing ,and if oil is getting around timing gears etc you would get oil/vapour come out of breather hole , obviously put valve back in when riding bike

My B33 has been bored and stroked to 597cc , it seemed to weep oil around barrel studs , I took off a old cover that used to drive a rev counter on the timing cover and , it had so much windage ,so I made a breather tank ,  .works great ,motor stopped leaking oil . Try to add pic but my file was too big .

[Bigsingle]

You would normally feel the engine breathing yes ,if you take out the valve and start bike with out it in you would /Should hear it breathing ,and if oil is getting around timing gears etc you would get oil/vapour come out of breather hole , obviously put valve back in when riding bike

My B33 has been bored and stroked to 597cc , it seemed to weep oil around barrel studs , I took off a old cover that used to drive a rev counter on the timing cover and , it had so much windage ,so I made a breather tank ,  .works great ,motor stopped leaking oil . Try to add pic but my file was too big .

[neil1964]

Looks very neat.
Where do the brass outlets go (chain lube?)
and how much oil do you find in the breather?

[Derek996]

Have a look at the breather system on this M24 based racer. The huge catch tank has hoses from the drive see original breather, from the breather on the later timing side cover and 2 addition breathers from the rocker box. It has  tap underneath to drain off any oil collected.

[Rog1]

Looks very neat.
Where do the brass outlets go (chain lube?)
and how much oil do you find in the breather?

Just what I was wondering.

[Bigsingle]

I drilled and tapped the timing cover to ⅜ bspt and the inlet rocker cover to ¼ bspt  they are plumbed to the tank , it has a k&n type filter on it ,at a later date if i find some good non return valves I might try them , which might create  some crankcase vacuum all the hoses go upwards first which helps stop oil getting to the tank ,i have only just made the tank and done about 100km  my engine has a bore and stroke of 94x90  tank has taken the pressure out of the crankcase , I haven't checked my drain yet but don't expect too much if any . Cheers. .

[Rog1]

I drilled and tapped the timing cover to ⅜ bspt and the inlet rocker cover to ¼ bspt  they are plumbed to the tank , it has a k&n type filter on it ,at a later date if i find some good non return valves I might try them , which might create  some crankcase vacuum all the hoses go upwards first which helps stop oil getting to the tank ,i have only just made the tank and done about 100km  my engine has a bore and stroke of 94x90  tank has taken the pressure out of the crankcase , I haven't checked my drain yet but don't expect too much if any . Cheers. .

Nicely done. I've been thinking about using a reed valve from some sort of 50cc 2-stroke moped in a breather box; it would certainly be able to respond quickly enough!
I expect your 597cc Beesa is quite torquey! Did you change the gearing?

[Bigsingle]

It is quite torquey , it has a small 30mm dellorto,  I'm not sure what size front sprocket I've only recently bought the bike and I'm trying to fix the problem issues,  I'm working on the front brakes , forks and steering head bearings at the moment , the rest of it is pretty good. Cheers.

[neil1964]

My ABSAF 600 motor has a reed valve  breather in the large bore pipe fitted to the upper part of the timing case (where a DBD has its disc valve). Jan does not fit the disc just uses the reed valve.

[Derek996]

I currently have the primary chaincase off my B32 and have been looking at the rather crappy breather valve. It's the same as fitted to the timing cover of the later bikes but is fitted to the main bearing housing instead. It has the same little fibre disc clack valve in it which really doesn't seem to work very well. I intend to fit a check valve in the hose downstream of it so that a partial vacuum is created in the engine. But I'm additionally considering two other options.
1. Fit an addition breather to the inlet rocker cover using the same check valve in the same direction, to allow air out but not in creating a vacuum internally,
2. Fit an addition breather to the inlet rocker cover using the same check valve in the opposite direction. This will allow air to travel into the top of the engine and get pumped out the bottom breather taking fumes and condensation with it. As long as the inlet is restricted it should create a partial vacuum in the engine helping to reduce oil leaks but given the location of the bottom breaker it might also carry a lot of oil with it. If it doesn't work I can just reverse the check vale in addition top breather.
These are the valves I'm using.

[DAVE BRADY]

Hi,

I fitted a breather on a Golden Flash rocker cover as many people have done over the years.  The pipe is probably 5/16 so not huge but enough to let a bit of excess pressure out.  However, to avoid any bits potentially being sucked up the pipe I shoved a Schrader valve from an inner tube in the open end of the pipe.  Seems to work.

It would have been interesting to have left the inner tube attached to see how long it would take to inflate but that would have been silly.

Dave.