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Thread: Colortune for HD8 Carbs?

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    Jedi Hopeful wangdango's Avatar
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    Colortune for HD8 Carbs?

    I would like to buy a Colortune to help tune my carbs, I see there is several sizes available, what size works with a HD8 Su? Is the purchase worth it?
    Thanks
    Ed
    wangdango

  2. #2

    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by wangdango View Post
    I would like to buy a Colortune to help tune my carbs, I see there is several sizes available, what size works with a HD8 Su? Is the purchase worth it?
    Thanks
    Ed
    My only complaint about the Colortune is that it seems tremendously expensive for a small handful of plastic parts. I bought my kit back in the '80s when the price was more reasonable. I like it. It works well. I didn't know they came in different sizes. I no longer have the box it came in, so I can't check that for any part number or size.
    Steve Byers
    HBJ8L/36666
    BJ8 Registry
    Havelock, NC

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    Great Pumpkin Keoke's Avatar
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    Re: Colortune for HD8 Carbs?

    Colortune to help tune my HD8 Su carbs?

    Is the purchase price worth it?----------> IMOP NO!

    There are other SU carb tuning kits that do an excellent job.
    1966 Daimler V8 Saloon; Safely Fast, Built to Last & and; Smooth as Glass.
    1966 BJ8 [ 2 ] Lil Red & Miss bLU
    1985 XJ6 Saloon
    1948 & 70 Lincoln continentals
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    Yoda tahoe healey's Avatar
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    Re: Colortune for HD8 Carbs?

    I think they are terrific! But the best results are when you have two to compare the flame colors simultaneously. The are very reasonable on Ebay. The sizes are for the different type plugs. Motorcycles use a smaller plug. I believe it is the 14mm you need.

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    Obi Wan Patrick67BJ8's Avatar
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    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by Keoke View Post
    Colortune to help tune my HD8 Su carbs?

    Is the purchase price worth it?----------> IMOP NO!

    There are other SU carb tuning kits that do an excellent job.
    What other kits are you referring to?
    Patrick
    '67 Metallic Golden Beige/Red
    Owned since '72

  6. #6

    Re: Colortune for HD8 Carbs?

    If you synchronise the butterflies properly, make sure the float height is correct and set you jets (on HD8s) down 0.075" down from the jet bridge, the carbs will be as near perfect as you get.

    do bear in mind that if you're still on original needles, the car may be weak and a rolling road is the safest bet. Otherwise, search for an SU needle chart and go for 10% richer through the range. It's what modern fuel needs.

  7. #7
    Jedi Knight RAC68's Avatar
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    Re: Colortune for HD8 Carbs?

    Hi All,

    I have acquired 2 Colortune units over the years in response to the idea that it would be better to use one on each HD8 to reveal the best adjustment results. Sadly, I have never been successful adjusting my carburetors with a Colortune, either one at a time or both together. In specific, I have not been able to see the color difference and would appreciate knowing what others are seeing. Also, I have even tried using the Colortune at night with minimal ambient lighting and still find no success in determining color changes when adjusting the carbs. I would like to use these units but have not.

    I do think wonder how available Rolling Road facilities are in the UK as I have not seen much of their presence in the US. I can see that adjusting a number of settings could be more effective when made in such a dynamic facility. However, the cost could be prohibitive.

    Ray(64BJ8P1)

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    Great Pumpkin Keoke's Avatar
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    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by Patrick67BJ8 View Post
    What other kits are you referring to?
    The Standard SU balance Kit is one that works well.

    However,The following by EV2239 is excellent:

    "If you synchronize the butterflies properly, make sure the float height is correct and set you jets (on HD8s) down 0.075" down from the jet bridge, the carbs will be as near perfect as you get."

    OH! Fore I forget:
    A set of Grosse jets replacing standard type needles will help a lot here too.
    1966 Daimler V8 Saloon; Safely Fast, Built to Last & and; Smooth as Glass.
    1966 BJ8 [ 2 ] Lil Red & Miss bLU
    1985 XJ6 Saloon
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    1973 Volvo P1800ES

  9. #9
    Darth Vader
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    Re: Colortune for HD8 Carbs?

    I've had/used 2 Colortunes for many years. On my BJ8, I put them on #2 and #5 cylinders. For years, I couldn't get any color on #2; come to find out that cylinder was all but dead with only about 60PSI compression. After an overhaul, I could get the coveted 'bunsen blue' on #2 and #5. I used 2 as well on our BN2, and was able to get blue on 2 cyls after an overhaul--didn't test before as we started a resto almost as soon as we got the car--and that engine has 160-170PSI compression on all 4.

    You should be able to get a yellow flame if the cylinder is running very rich; I think as you lean the color may change from yellow to invisible without passing through blue if the cylinder is weak, or maybe other anomalies can cause it.

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    Yoda tahoe healey's Avatar
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    Re: Colortune for HD8 Carbs?

    Ray, I'm not sure why you are having trouble unless you are using the crappy mirrors supplied. If you look directly down the "plug" you get a very clear picture of what is going on.
    I have a lot of other tuning devices including the tube float device. On a BJ8 you must remove the front air filter. A real pain.
    The Gunison fuel analyzer sits in the box (new) because it is too complicated. There is an inexpensive set of wires that fits into the top of the dash pots that works fairly well.

  11. #11

    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by tahoe healey View Post
    Ray, I'm not sure why you are having trouble unless you are using the crappy mirrors supplied. If you look directly down the "plug" you get a very clear picture of what is going on.
    I have a lot of other tuning devices including the tube float device. On a BJ8 you must remove the front air filter. A real pain.
    The Gunison fuel analyzer sits in the box (new) because it is too complicated. There is an inexpensive set of wires that fits into the top of the dash pots that works fairly well.
    The mirrors are pretty crappy, being just chromed plastic. Mine finally broke off, so I get a better view straight down the tube. The SU tuning kit wires that fit into the dash pot tubes indicate whether the air flow is balanced (equal) through both front and rear carbs, but they don't indicate proper mixture which is what the Colortune does. You're supposed to turn the mixture screw for the carb until you get a rich (yellow) flame, then back it off gradually until you get the Bunsen blue color. You have to be able to judge the difference between Bunsen blue (perfect mixture) and whitish blue (lean). If you get it right, you'll have a gray deposit in the tail pipes and gray or light tan on the plugs. Too rich, and the deposit will be black. If you have trouble getting the blue, the Gunson instructions that come with the kit give you some reasons why that might happen.
    Steve Byers
    HBJ8L/36666
    BJ8 Registry
    Havelock, NC

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    Darth Vader John Turney's Avatar
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    Re: Colortune for HD8 Carbs?

    I don't use the tubes. I just look at the (clear) plugs. The pair I have work fine. The difference between yellow and blue is about a quarter turn on the mixture adjustment on my HD8s.
    John, BN4

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    Jedi Knight dougie's Avatar
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    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by RAC68 View Post
    Hi All,

    I have acquired 2 Colortune units over the years in response to the idea that it would be better to use one on each HD8 to reveal the best adjustment results. Sadly, I have never been successful adjusting my carburetors with a Colortune, either one at a time or both together. In specific, I have not been able to see the color difference and would appreciate knowing what others are seeing. Also, I have even tried using the Colortune at night with minimal ambient lighting and still find no success in determining color changes when adjusting the carbs. I would like to use these units but have not.

    I do think wonder how available Rolling Road facilities are in the UK as I have not seen much of their presence in the US. I can see that adjusting a number of settings could be more effective when made in such a dynamic facility. However, the cost could be prohibitive.

    Ray(64BJ8P1)
    Rolling Roads or "Dynos" are widely used out here in the Wild West. There's about half a dozen right here in Portland, OR. I test my '57 vintage racer before every season. I used a new shop this year, Portland Speed Industries, $175.00 for about an hour and a half for baseline settings. Well worth the money, I was way lean which both spark plugs and exhaust residue didn't indicate after a track day at PIR.

    Portland Speed Industries Dyno.jpg

    http://www.tunedbypsi.com/services.php?Dyno-Info-3
    Dougie
    '65 BJ8 3000 MKIII GN.29
    '57 100-SIX MM Vintage Racer GN.1 #414
    Team Healey PDX

  14. #14

    Re: Colortune for HD8 Carbs?

    Agree with that Dougie. I take my car to a rolling road once a year. Everything gets set up up correctly and then you must LEAVE IT ALONE! Stop fiddling.

  15. #15

    Re: Colortune for HD8 Carbs?

    They used to work pretty well for me in the days of non unleaded fuel. Not so good anymore. I need to go much richer than bunsen blue.
    This Jedi stuff is not really cute. I recommend the administrator get rid of it.

  16. #16

    Re: Colortune for HD8 Carbs?

    They used to work pretty well for me in the days of non ethanol fuel. Not so good anymore. I need to go much richer than bunsen blue.
    This Jedi stuff is not really cute. I recommend the administrator get rid of it.

  17. #17
    Darth Vader Marvin Gruber's Avatar
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    Re: Colortune for HD8 Carbs?

    I'm not impressed with it.
    Marv

  18. #18
    Obi Wan Patrick67BJ8's Avatar
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    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by EV2239 View Post
    If you synchronise the butterflies properly, make sure the float height is correct and set you jets (on HD8s) down 0.075" down from the jet bridge, the carbs will be as near perfect as you get.

    do bear in mind that if you're still on original needles, the car may be weak and a rolling road is the safest bet. Otherwise, search for an SU needle chart and go for 10% richer through the range. It's what modern fuel needs.
    What tool is available to measure the 0.075".
    thanks
    Patrick
    '67 Metallic Golden Beige/Red
    Owned since '72

  19. #19

    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by Patrick67BJ8 View Post
    What tool is available to measure the 0.075".
    thanks
    Use a dial caliper.
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
    Check out my galleries:
    http://www.pbase.com/stevegerow

  20. #20

    Re: Colortune for HD8 Carbs?

    Quote Originally Posted by EV2239 View Post
    If you synchronise the butterflies properly, make sure the float height is correct and set you jets (on HD8s) down 0.075" down from the jet bridge, the carbs will be as near perfect as you get.

    do bear in mind that if you're still on original needles, the car may be weak and a rolling road is the safest bet. Otherwise, search for an SU needle chart and go for 10% richer through the range. It's what modern fuel needs.
    What jet would you recommend to be 10% richer. Have heard that number before but without a jet suggestion.

    Correction: What needle...? Sr moment
    Last edited by steveg; 08-20-2017 at 08:59 AM.
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
    Check out my galleries:
    http://www.pbase.com/stevegerow

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