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Engine breather


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Hi guys


After sitting for a year waiting for a restoration,  we tried to start the motor (M10) and other than a tired battery, it started up after a few tries! Question is, currently the crankcase breather is disconnected to the factory air box due to running a 32/36 carb, but the breather tube is shooting out a little bit of smoke at start up..is this normal?

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Yep, especially if


1. the engine has some miles on it

2. it's been sitting for awhile

3. the engine is brand new and not yet broken in

4. valve stem seals are old and/or the original style


If you're not running the stock air cleaner that has a provision for the breather hose, you should route the hose into  a catch can, or run it down to the level of the oil pan so it'll "breathe" onto the road.  This latter solution isn't the most ecologically friendly, but it's how engines were vented well into the 60s.  


Better you either get the adapter or modify your stock air cleaner to mate with the Weber carb.  Not a difficult task (ten minutes with tinsnips or a Dremel, or buy an adapter) and works much better (cool outside air for the engine, more air cleaner surface so more time between cleaning/replacing the filter) and a place for the breather tube.  




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I have just completed the same task. New engine with DCOE's.


I vented to road whilst I wait for this catch can, which I will modify a little to accept a mini filter:




Although for neatness and originality I would like to plumb the crankcase vent to the air filter of the carbs.... perhaps at a later date.

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