swedishbiker wrote on 10/13/13 at 16:52:06:


BACON!!!

With the stock CV carb, the petcock valve and fuel line need 8mm (ok, 5/16” is ok since more readily available and more common in US).  Stock is 8mm is a smidge bigger than 5/16” though.  While a 1/4” valve and hose may seem close, it’s about 1/3 smaller in volume/diameter than 8mm.  Remember Pi r2 math and the stock carbs are designed to suck at this proportion.  This is needed for the vacuum operated aspect of the carb.  Now, if you are just using gravity fed operation of the carb, the 1/4” stuff is fine.  The bike will never be able to swallow more gas than the 1/4” line/valve can provide even up to high rpms.  Similarly, a gravity fed carb, like the cheap knock-off PWK40 I’m experimenting with on my project bike, does just fine with 1/4” valve and fuel line.  I’m using a $7.99 e.Bay Chinese petcock valve on it.  If it craps out in a year or two, fine.  It has decent filters built in (main and reserve), so for $7.99 for a valve with good fuel filters - deal!  Free shipping too!