Author Topic: Green/grey coating coming off carbs after Berryman's dip  (Read 3141 times)

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Offline emitch

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Green/grey coating coming off carbs after Berryman's dip
« on: October 07, 2011, 07:09:11 PM »
I dipped my carbs in some berrymans chem dip, and hit 'em with a wire brush afterwards. The dip and brushing started to strip some of the greyish coating from the outside and inside of the carbs. The outside now looks silverish, while the inside of the carbs look a bit spotty with some of the coating being stripped. Is this normal, and will it hurt the carbs to run them like that?

Also, after I let it dry there seems to be a fine dusty residue in the float bowl area - i'll try and remove as much of it as possible, but is it alright to have fuel in these carbs with a little of the residue in the bowl areas?
« Last Edit: October 07, 2011, 07:29:49 PM by emitch »

Offline HondaMan

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #1 on: October 07, 2011, 07:43:26 PM »
What you're seeing now is how they looked when new!
The carbs have corroded from the years since. The white powder is also corrosion, and you want to hunt that stuff down with a vengeance and kill it off. If you don't, it likes to collect in the emulsifier tube holes (if not the pilot jets) and the emulsifier air bleed passage(s), causing issues.
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Offline emitch

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #2 on: October 07, 2011, 07:56:21 PM »
What you're seeing now is how they looked when new!
The carbs have corroded from the years since. The white powder is also corrosion, and you want to hunt that stuff down with a vengeance and kill it off. If you don't, it likes to collect in the emulsifier tube holes (if not the pilot jets) and the emulsifier air bleed passage(s), causing issues.

Thanks Hondaman. I actually thought the coating was a factoring paint/primer or something. Glad to know its actually corrosion. I've gotten the outside all good and shiny, but the insides are a little rough and spotty as it's tough to get the wire brush in there.

Offline Kermit

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #3 on: October 07, 2011, 08:28:15 PM »
i'm in the same boat, any tips on getting everything cleaned up?

Offline HondaMan

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #4 on: October 08, 2011, 08:35:49 PM »
I use Q-Tips (a lot of them) after total disassembly of each carb. My favorite high is lacquer thinner: having a lit candle nearby (BEFORE you start using it, not AFTER the fumes build up) will keep the fumes at bay by burning them off in the air as they appear (a trick I learned from someone who used to paint model trains for a living). Acetone almost works as well, mineral spirits not so much. The green CRC brake cleaner spray is also excellent, but expensive to use, for removing thick layers of the gunk in nooks and crannies. Gently scrub the floats with a brass toothbrush (like in the detailing kits for cars, at auto parts stores) to remove buildup on them. Don't soak the plastic floats in acetone or lacquer thinner, but the brass ones are OK for that.

Be sure to clear the air passage between the air horn (little brass hole) and the emulsifier tube (aka mainjet holder) with a mechanic's wire. A little corrosion in there makes for a real rich mixture later.
See SOHC4shop.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book
Link to My CB500/CB550 Book: https://www.lulu.com/search?sortBy=RELEVANCE&page=1&q=my+cb550+book&pageSize=10&adult_audience_rating=00
Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

Offline MrGardman

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #5 on: October 10, 2011, 04:38:13 PM »
I use Q-Tips (a lot of them) after total disassembly of each carb. My favorite high is lacquer thinner: having a lit candle nearby (BEFORE you start using it, not AFTER the fumes build up) will keep the fumes at bay by burning them off in the air as they appear (a trick I learned from someone who used to paint model trains for a living). Acetone almost works as well, mineral spirits not so much. The green CRC brake cleaner spray is also excellent, but expensive to use, for removing thick layers of the gunk in nooks and crannies. Gently scrub the floats with a brass toothbrush (like in the detailing kits for cars, at auto parts stores) to remove buildup on them. Don't soak the plastic floats in acetone or lacquer thinner, but the brass ones are OK for that.

Be sure to clear the air passage between the air horn (little brass hole) and the emulsifier tube (aka mainjet holder) with a mechanic's wire. A little corrosion in there makes for a real rich mixture later.

Great idea about the candle with the lacquer thinner.  I will remember that the next time I need to clean carbs up.

Offline Kermit

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #6 on: October 10, 2011, 05:21:02 PM »
When cleaning my carbs yesterday i noticed they went from a greenish color to a dark grey by the time i finished. I didn't notice anything peeling or anything, just the slight color change.

Offline CycleRanger

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Re: Green/grey coating coming off carbs after Berryman's dip
« Reply #7 on: October 10, 2011, 08:17:19 PM »
Zinc alloy carb bodies were commonly treated with chromate, a chromic acid process, that imparted the gold/green color to the bodies and provided some protection against the formation of zinc oxide, the white residue you find on old carbs.

Chromic acid is also known as hexavalent chromium, the stuff that was at the center of the Erin Brockovich movie.


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