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Discussion Starter #1
Have any of you gone fron a timing hole breather to a timing cover breather system ?.
Has it helped with the oil blowing out the breather tube ?.
What's your opinion on a better way to go.
Thank you as always.
Bill
 

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I'm not sure what you are asking? Are you talking about the timing hole behind the cylinders?
 

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Discussion Starter #3
I'm not sure what you are asking? Are you talking about the timing hole behind the cylinders?
Exactly, when I got the belt drive dry clutch set up, it came with a breather system that goes through the timing plug hole.
My engine spits a lot of oil directly off the crankshaft, it coats the back of my bike so I don't have to worry about rust, that's why I was asking about anyone with experience with the breather going through the timing cover.
I'd like to keep the majority of the oil in the tank.
 

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Hi Bob
You have to be careful in the timing cover also,
The pressure relief valve has two oil dump ports, on into the crankcase the other into the timing chest, this oil is picked up by the timing gears and flung about in the timing chest, it is full of oil mist just ready to be drawn out of the engine by the breather draught. I have tried a breather in the timing cover but it was a struggle to keep oil out of the breather tube.
There is an internal chamber neat the front engine mounting, people have a lot of success with modifying the crankcases and fitting the breather here. The downside is that you to completely strip the engine to make the modification.
Regards
Peg.
 

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My dual engine land speed racer breathers...Zero oil blows out even at 7000 plus rpm...I did the same on a unit 650 engine with a 750 kit asxthe 9nly breather...after about 100 miles a few oil dropswould form at the breather tube exit...

746777
 

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Discussion Starter #6
My dual engine land speed racer breathers...Zero oil blows out even at 7000 plus rpm...I did the same on a unit 650 engine with a 750 kit asxthe 9nly breather...after about 100 miles a few oil dropswould form at the breather tube exit...

View attachment 746777
First things first, damned nice scooter.
I myself think anything away from the crankshaft has to be better than what it is now.
I also understand a dribble of oil, that's what I'm hoping for, a dribble is normal.
 

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that front cavity where the motor mount bolt runs through is where i put the breather on my last two 1970 LSR motors. i had put a dry belt on this machine and needed to isolate th eprimary from engine oil, so i installed a crankcase seal and had to re-locate a breather

to put a breather up front, you can drill and tap the cavity for a spigot. i put them on the top, but they work on the sides as well:



drill some 1/4-inch equalizer/drain holes into the crankcase:



put in some stainless mesh to keep oil splash out of the tubing:



screw in a hose barb spigot



run some hoses to the rear:



if you want, you can also vent the crankcase from the rocker boxes. the pressure balancing from these is not negligible:





i use a catch bottle back there, as this is a race bike. but just an open breather works as well, so long as you run it all the way to the end of the fender so it doesn't drip on the rear wheel.



mine blows much more than a few drops without a catch bottle, and alarmed my neighbor in th epits who runs an immaculate ZX14. i told him the back of my bike always looked that way and he calmed down.
 

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Exactly, when I got the belt drive dry clutch set up, it came with a breather system that goes through the timing plug hole.
My engine spits a lot of oil directly off the crankshaft, it coats the back of my bike so I don't have to worry about rust, that's why I was asking about anyone with experience with the breather going through the timing cover.
I'd like to keep the majority of the oil in the tank.
Ok, Now I understand. I always thought the vent through the primary was an improvement to the Triumph engine. However, it does screw up the option of a belt drive / dry clutch.
 

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how have you run the breather pipe from the timing hole ? - have you tried running it straight up as high as possible to the underside of the fuel tank before turning it to the rear of the bike - might give any oil time to drain back - just a thought !
-- and what diameter hose - bigger is better i would think
 

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I have seen some breather pipes that are 1 inch diameter which would slow the air speed and therefore less oil would be taking air pressure carrying it up and out. I would agree with WOL on larger pipe.
Interesting, that my primary case vented normal engine, emits no oil and virtually no air can be felt coming from the end of the pipe.
 

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The hoses I use are 7/8 ID....Not seen on my double are the rocker box 1/4 inch breather hoses.No catch cans becuase the don't drip oil...
My single engine racer has a front breather hose like Speedrattle plus a 5/16 hose from the timing cover.
 

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Discussion Starter #12
how have you run the breather pipe from the timing hole ? - have you tried running it straight up as high as possible to the underside of the fuel tank before turning it to the rear of the bike - might give any oil time to drain back - just a thought !
-- and what diameter hose - bigger is better i would think
I do have the breather pipe going straight up till the fuel tank, then follow the normal placement of the hose along the left side rear fender.
 

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Hi Bob, How are you breathing the frame? I've found during hard breaking down hill oil will run up top tube & drain down the vent hose back to primary.

The later bikes have frame vent to top of exhaust rocker boxes. The thought of breather from top end is interesting. I've ran my motor with valve covers off to observe oil flow. Very minimal splash up there. The 2 oil drain holes in tappet block are similar size as 2 breather holes on cam end disc, if you vented both boxes. Then use check valve like off Yamaha 650 or Norton breather kits. With good rings the cam disc breather works well & can even create negative pressure in breather hose.

An interesting puzzle. I'd think the TDC plug hole vent would put out more oil than could drain back??

Here's breather on '69 Bonnie for reference. The Triangles only line up fully for a moment as pistons fall. They are covered as pistons rise. I don't know this, but breather hole (1/4") in hollow cam might act as centrifugal oil separator??
Don
 

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