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Re: Burning Rich HElp

To: "Paul Osborne" <>, <>
Subject: Re: Burning Rich HElp
From: "Paul Hunt" <>
Date: Fri, 6 May 2005 15:40:13 +0100
How are you using the Colourtune?  Because your car has twin HIFs with a
balance pipe the combustion in *any* cylinder is dependant to some extent on
both carbs.  When making an adjustment to one carb, which ostensibly is
feeding just two of the cylinders, it does have an effect on the other two,
so you have to make a small adjustment to that carb.  That then has an even
smaller effect on the first two cylinders, so you have to make an even
smaller adjustment back on that carb.  Two or three iterations is usually
required to get both right.  The only way a Colourtune can be used is by
continually moving it back and fore between cylinders 1 or 2 and 3 or 4
whilst you fine tune each carb, or using two of them.  And I never had much
luck with a Colourtune on a single carb engine.  I always have good results
from using the lifting pin and Mk1 ear on both HSs and HIFs, although the
fine tuning *is* more tricky on HIFs, being almost subliminal.  But all you
have to do is be able to identify when each carb is rich and when it is
weak, and position it between those two points.


----- Original Message ----- 
> >Engine starts with no problem warms up,
> >running though it burns rich. Black soot on plugs, same in the
> >exhaust pipe,and rather high fuel consumtiom.
> >Idle seem ok. Have tried a color tune and seems to be right on. I

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