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Discussion Starter · #1 ·
Has anyone got any pictures or good ideas about triumph 650 rocker box breathers ? I have always struggled to get the top ends oil tight on triumphs and think breathers might help.
 

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Discussion Starter · #4 ·
Forgive me but i was under the impression that the scavange side of the oil pump was of larger capacity then the feed side, this means this side of the pump for some of its time is pumping air along the return oil line and so air gets to the rocker boxes, no ? This means the rocker boxes are pressurized with air, its this air i want to vent , but i am looking for a neat and tidy solution.

The gasket surfaces have been lapped on a surface plate and are flat, i will be using copper gaskets, but these surfaces are narrow and i think any pressure is enough to force out oil.
 

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Discussion Starter · #6 ·
Bon, the return side of the pump is larger,that is true, but only slightly,and it dumps into your oil tank with only enough restriction to back some of the oil up to the rockers.I've had clear line on a rocker feed before and never saw enough air in the line to say it was significant. The pressure in your rockerboxes is Crankcase Pressure. It is the same pressure everywhere inside the motor that is connected to the c/c. Relieve it one place, it is relieved everywhere. The notion that air from the return side of the oil pump is causing leaks at your rockerboxes is IMHO wrong. Jack
Thanks jack , i haven't built the engine yet , just working on the various bits and want to get it right first time and not have to rework anything, i wonder does the oil passing through the tappet block holes cause an obstruction to air passing down into the crankcase ? I will plumb in a couple of small hosetails in the rocker box caps and link them up to the main crankcase breather.
 

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Discussion Starter · #10 ·
Sorry everyone i should have been clearer , its a pre-unit alternator engine , as i will be running an alternator i welded a points housing into the timing cover because i want to run a boyer ignition , so i have the space normally taken up by the magneto to play with, i was going to mount the oil filter here but don't see why a breather can't be taken from here too.

Thanks.
 

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Discussion Starter · #17 ·
Bon, Haven't built the engine yet? That changes everything, if you want to do it right, research one-way valves. If plumbed correctly,you can get neg. c/c pressure and that equals less leaks and more power.It may not be much in the power increase,but every bit helps and it's "free". Jack
Thanks for the helpful replies everyone. Jack is there a specific valve i should be looking out for ? A commonly available one from a car or truck or machine or something ?
 

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Discussion Starter · #32 ·
I am going to use the breather with the reed valve set from a yamaha xs650 as recommended by the guys on here , this is to create a small vaccum in the crank case , but if i have open vents from the rocker box caps the air will flow in through them and be drawn down into the crank case and be pumped out from the main breather so no vaccum, i was going to use small non-return valves as used in pneumatic systems on the rocker caps, any comments ?
 
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