Colortune

Color Tuning the carb.

Question:

Has anybody out there ever used the Color Tune for tuning the carburettor ?
It enables you to see the colour of the flame inside the cylinder.The flame should be blue when the carburettor is set correctly and if it's yellow the mixture is too For example the weber 45 has 4 different systems idling, low speed,normal speed,high speed (I read the weber manual :-). I know how set the mixture at idling but how about the> others ?
The manual just explains how the carb. works not really anything about how to tune it. I thought that the Color Tune might be one solution because im suspecting the carb. running too rich and I don't want to leave the car to an expensive garage ;-)).

From: David Allen ,Me. USA dandr@gwi.net on 4/4/1997 13:46

Jhonny: Keep reading that manual. Make sure the float level
and fuel pressure is correct. Remove the carb and adjust the
idle speed screw, so only the idle mixture screw port is
exposed. Do not adjust the speed screw after that, warm the
emgine up and adjust the mixture screw to best idle. Note
how far in or out the screw is, compare that to what the
book says[3/4 turn out?].If you have to turn the screw way in,
install smaller idle jets in both sides of carb.
Once you have the correct idle jet, you can start to work with
the idle air corrector. Keep reading that manual.

Good Luck
Dave

From: Jhonny Sokura, Vadstena, Sweden on 4/4/1997 19:39

Dave ,

Well my manual doesn't give me any good advise on how
to proceed just basic information about the specs. for
the carburettor.
What I really want is a manual that explains the procedure
step by step about tuning it.I think I have to look for
a more general manual on carburettor tuning instead.The
reason is that I want to learn how set up the carb. from
start.
I thought that by seeing the colour of the flame it would
be easier to tune the carburettor.Especially on higher
rpm's when various systems are engaged.

Regards,

Jhonny

From: David Allen ,Me. USA dandr@gwi.net on 4/4/1997 22:01

Jhonny: I've never used a Colortune, do'nt see why it will not
work.Haynes has a manual on Weber carbs. Did you ever determine
what main venturies {chokes} you have? How about idle jet sizes?
You can spend HOURS tuning that carb to perfection!
Do'nt give up
Dave

From: Jhonny Sokura, Vadstena, Sweden on 5/4/1997 13:52

My current configuration is what's suggested in the
Weber manual and for the MGB that is:

Chokes: 38
Aux. venturis: 4.5
Main jet: 155
Emulsion tubes: F16
Air correction jet: 160
Idling jets: 60F8
Needle valve: 2.25
Pump jets: 60

No modifactions are made to the engine.Standard MGB.

/// Jhonny

From: David Allen ,Me. USA dandr@gwi.net on 5/4/1997 15:01

Jhonny: 38 mm chokes are pretty big, unless you drive at high
speed most of the time? Smaller chokes will pick up the air
speed through the carb. the carb will love it, you will too!
You might not notice any loss in high speed performance with
smaller chokes and a stock engine. I'd try 32 or 34mm first
you can always bore them out on a lathe, to make them bigger
if need be. Idle jet @ 60 sounds a little large too. How far
out is the idle mixture screw?

Hope this helps
Dave

From: Dave dandr@gwi.net on 5/4/1997 15:06

One more thing: My Stage V 2130cc Volvo used 40mm chokes and
i do'nt think we ever went below 4000rpm on road race tracks
Dave

From: C. Woodford, Mt. Sterling, KY USA cw@sprintmail.com on 5/5/1997 19:52

One more time...

I've had a difficult time working with Colortune. The
device always seems to indicate a too-rich mixture, regard-
less of the mixture adjustment. Finally had better luck
with the "lift 1/8" and see if it dies" process. Also,it
seems that the procedure is inherently made more uncertain
by the fact that you always have both carbs on line even if
the interconnect has been loosened. Having spent $35 (or
whatever), I would like to know where I err.

From: WDHound@aol.com on 5/5/1997 20:17

Did the same thig 5-6 years ago & had same results.I have dual HS4 carbs. Have color tune for sale cheap.

From: Jim in CO, JJWILLETT@aol.com on 5/5/1997 20:45

I've had the same experience with the Colortune. Although it was fun to play with, I found it no easier or acurate than following the basic tuning procedure found in the Haynes Manual. And it it definately no substitute for a good CO meter.

JW.

From: c woodford, mt. sterling, ky. cw@sprintmail.com on 8/5/1997 21:20

Jim, I assume that the CO meter worked for you. What did
you buy and how much did you pay? Are they really worth-
while in terms of cost v. benefit? Assuming that the Haynes
method is the "lift the piston and see if rpms increase"
technique, I'm not sure how reliable it is.

From: Jim in CO, JJWILLETT@aol.com on 9/5/1997 16:26

The CO meter I used was one at a local garage that I "borrowed" time on. I do not own one.

However, in using this equip., I was surprised by two things - 1. a small adjustment to the mixture settting can make a big change in CO and - 2. You can make big changes in CO output with little to no percieved change in how the engine idles. Tbe colortune seemed to have little sensitivity in this area (but then again I may be color blind). I know that Moss sells a "relatively" inexpensive CO meter, but I have no idea if it is any good or not. Maybe someone else on this BBS has used one?

If you live in an area with tight emissions requirements, I would say that doing the final tune with a CO meter is almost mandatory. Especially if you've 'tweeked' your engine any.

JW.

From: C. Woodford, Mt. Sterling, KY cw@sprintmail.com on 9/5/1997 23:22

To be honest, I have no emissions concerns at all. We are
sufficiently consumed with tobacco smoke here in Kentucky
that it makes no difference at all. My primary concern is
that the engine run well, uncaring devil that I am. Anyway,
I'll check out Moss and others. Thanks again.

From: Richard Smith, New Orleans, richsmit@ix.netcom.com on 12/5/1997 14:47

I have two Color tune plugs and they were good for getting
in the ballpark only for SU's.

Since I switched to the Mikuni side draft, I have used the
color tunes once.

Color tunes are a great idea but since you CANNOT simulate
true load conditions,i.e. car on road, you can only set
the mixture to be absolutely correct at idle and with no
load thru the revs.

For a long time I've wished for a way to see the damn thing
while driving down the road (you can't really sit in the
engine bay while driving).

A little on the Mikuni. I have heard so many woes about
the Weber side draft that I don't want to be anywhere near
one. The Mikuni looks and performs like a Weber but once
set (get ready to spend HOURS) it just runs. NO MORE
CONSTANT TUNING!

The Mikuni is cheaper too. When I bought mine in 1988,
complete setup with manifold and linkage was $325 at a time
when the Weber was about $500.

The Mikuni also has a PROPER (meaning no vacuum advance at
idle but vacuume advance when off idle) vacuum tap for the
advance. You can actually have reasonable fuel economy and
a decent idle.

You can get the carb from Mikuni North America in CA. Just
call 800 directory assistance and ask for the number.

From: RICK BRANCH BRANCH@MAIL.AMERITEL.NET on 13/5/1997 3:20

I ALSO PURCHASED THE COLORTUNE KIT FOR ADJUSTING MIXTURE ON SU'S. I DID NOT HAVE VERY MUCH LUCK. I DID NOT SEE MUCH COLOR CHANGE WHENEVER I CHANGED THE MIXTURE. I NEVER TRUSTED THE LIFT THE PISTON METHOD BECAUSE IT DID NOT MAKE SENSE. I TOOK MY CAR OUT OF MOTH BALLS AFTER SEVEN YEARS AND REBUILT THE CARBS. AFTER SETTING THEM UP WITH THE COLOR TUNE, I HAVE BEEN SLOWLY ADJUSTING THEM BASED ON THE COLOR OF THE TAIL PIPE. I KNOW THIS ISN'T GOING TO GIVE ME A GOOD INDICATION OF MIXTURE BALANCE BETWEEN THE CARBS, BUT IT WORKS FOR ME. I ALSO HAVE A COLOR TUNE FOR SALE CHEAP.

From: Jhonny Sokura, Vadstena, Sweden on 21/5/1997 10:08

Hi all,

I found an interesting tutorial on Weber 45 DCOE tuning at
http://www.tsquare.com/jtrindle/tscc/webertune.html.
Have a look. It seems to me that some valuable hints for
home brew Weber installations are given here.

/// Jhonny

From: Adrian Jones, NC adrianjones@compuserve.com on 11/6/1997 3:24

Hi folks,
I thought the Colortune came pretty close to getting the mixture right on my Midget.
I see someone is fine-tuning by going by the color of the exhaust pipe. Wouldn't it be a bit more accurate to go by the color of the spark plugs? I think i read somewhere that if you do this then turn the engine off as soon as you come into your driveway (ie no idling). That's what i done this afternoon and just as i was getting out the car, there was this incredible bang out of the muffler! We are having an MG meeting this Thursday so i think I'll try to repeat it!!
Anyway, wouldn't the color of the plugs tell you if you've got the mixture right? Black and sooty = rich, white = too lean, brown = just right. Mine are looking a definite reddish brown. What's the deal with the red. Is it the residue from some kind of additive?
Cheers, Adrian

From: Koen Weerheijm on 24/6/1997 19:26

I use the color-tune regular on different cars. It will work fine if:
- the carb's are in good condition and setup with the rigth needles for the cam, airfilter and exhaust,
- the pistonrings and valve guides are not gone otherwise
the burning oil will result in a yellow flame.

If you want to tune your Weber with a color-tune you will need a rolling-road to simulate the load on the car.
But then there are better ways to use that rolling-road for tuning the Weber !
Using a CO tester has (as I see it) not much to do with getting the best from your B, just with pleasing the law.