[TR] synching carbs

John Macartney standardtriumph at btinternet.com
Sun Nov 23 14:48:58 MST 2008


I've been following this general thread for almost all the time (I think) that its been running and 
I have to say I'm becoming disappointed in what appears to be the level of enthusiasm many are 
showing for the carb balancing device. Aren't we all getting a bit too over-dependent on gadgetry?
What's wrong with the 'old fashioned' way described ad nauseam in a plethora of workshop manuals and 
car handbooks?
Mixture strength can easily be checked by pushing the palm of your hand against the exhaust tailpipe 
to verify misfires and smoke - and to then 'smell' the palm for richness or weakness. Yes, you 
really can 'smell' it! Having then initially set the slow idle, you can use a short piece of garden 
hose pipe to one ear to compare the level and pitch of intake hiss. One of my 'tools' (and I copied 
it from many colleagues) was to use an old twin tube stethoscope. That way, on a twin SU set up, you 
can hear the hiss in 'stereo' and do the fine tuning that way. I later graduated to a single tube 
steth that in itself was extremely useful for diagnosing other internal rumbles and rattles before 
they became serious.
I guess some may think all this too non-scientific? For the record, I used those bits of equipment 
less than a month back to reset the carbs on the UK Raffle Spitfire before it went in for its annual 
(and mandatory) safety test. It fires up instantly from cold, the choke can be pushed fully home 
within two minutes and the exhaust emissions were within limits established for a car of its age. 
I'm no ace mechanic but you really can accurately set up a set of dual or triple SU's without having 
to resort to a colour tune and visual balancer and all achieving exactly the same result. What's 
more. countless thousands of people have done it too and its certainly not rocket science.

Jonmac 


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