Author Topic: Fine! I'll pull the god blessed carburators!  (Read 834 times)

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Offline eigenvector

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Fine! I'll pull the god blessed carburators!
« on: April 08, 2017, 01:13:01 PM »
How many of us have said that?  All of us I wager.  I probably say it more than most because it takes a while for information to seep into that concrete around my brain.  It seeps right back out much quicker though. :P

My thoughts on carburators in general:
If you have to resort to chemicals, surgery, fine tuning, self-mutilation in order to get the bike running (poorly) - pull the freakin' carburators and clean them again.

There is nothing magical or mystical about carburators and the function isn't so super sensitive that turning the pilot screw an extra 1/64 of a turn is going to magically get the bike running again.  There are optimal settings - but they aren't necessary for the bike to run, and run acceptably at that.  You should not have to use choke in order to idle.

I won't go into the various means and ways to do all this - far too many other resources out there.  However in general, factory settings are where you should start and if the carbs are clean and the plugs not fouled - the bike will run, first time too!

For all those saying - "what a freakin' hypocrite!"  Yeah - I am a hypocrite, because I piss and moan about this all the time and it all comes down to laziness.  I would hazard a guess that laziness accounts for 90% of the problems people have who say "I cleaned the carbs" right before launching into a tirade about how much they hate carburators.

General observations:
PD carbs are in general very tolerant of debris.  Their weakness - the fuel inlet valves leak like sieves.
CV carbs (Keihin Vx series carburators) are VERY sensitive.  The pilot and slow jet circuits really require concerted effort to clean out.  Not helped by the fact that testing the circuit is very difficult due to the small passages and the multiple paths the circuit takes.  I haven't found anything which will go through the pilot and slow jet passages on the VB and VE carburators.  Made even worse by the presence of the choke circuit.  Air leaks are the death of these carburators too.

In short - quit hosing the bike down with starter fluid and carb cleaner.  I know the airbox is scientifically designed to cause maximal pain and anguish.  Yes I know those once supple airbox boots could be used to deflect bullets now.  Really - pull the rack and clean them again.  Focus on that pilot circuit!
Rob
--------------------------------
2018 HD Softail Heritage
1979 CB750K Limited Edition
1977 CB550K
1984 CB700SC Nighthawk
1983 VF750S Sabre

Offline Trevor from Warragul

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Re: Fine! I'll pull the god blessed carburators!
« Reply #1 on: April 08, 2017, 05:43:29 PM »
A trick with CBX carbies.  Fill the clogged circuit with brake fluid, then heat with a propane torch until the brake fluid boils. 
1971 Kawasaki H1A
1972 Honda CB350F
1976 Moto Morini 3 1/2 Sport
1978 Honda CBX
1997 Suzuki Bandit 1200
1999 Ducati Monster 750