Topic: Carb Shine?

[peaches67rs]

Got a '78 CB750K, all original...refurbishing some parts. Carbs are next.

Anyone have any good solutions for cleaning the outside of the carbs with a chemical...like phosphoric acid?

Would they have to be dunked in a bath? Are there any hidden brass parts that the PA would destroy if not removed?

Thanks guys.

[Greggo]

Soda blast the bodies, and polish the bowls and tops with a buffing wheel..

[BobbyR]

I think you should stay away from chemicals. You can discolor the aluminum.

[MasterChief750]

acid will eat the aluminum. get some of the purple simple green and some small paint buckets and put all the parts in the tubs.mix the simple green 1:1 with water and let it sit for a few days. get a paint gun cleaning kit with all the little tiny brushes and clean out every little orifice. rinse everything with water and allow to dry rebuild and rerack your carbs and they will look shiny and new.

[KB02]

acid will eat the aluminum. get some of the purple simple green and some small paint buckets and put all the parts in the tubs.mix the simple green 1:1 with water and let it sit for a few days. get a paint gun cleaning kit with all the little tiny brushes and clean out every little orifice. rinse everything with water and allow to dry rebuild and rerack your carbs and they will look shiny and new.

+1 on this. That's what I did with the carbs on my K8. I don't have a before pic, but they were truly rust/crust masters.

[MasterChief750]

you can paint the bodies but it takes a ton of friggin tape, theres some pics in my build thread.

[fastbroshi]

Is your goal to get a true aluminum color?  If you just want them clean Simple Green will do the job perfectly, just don't leave them in it for more than a couple hours.  It will discolor them.

[Terry in Australia]

I've got a Borrani rimmed CB750 rear wheel that I need to re-spoke and re-hub. The tire is off it, but the ends of the spokes were really rusty so I couldn't unscrew the spoke nipples. I dunked the rim in a tub of phosphoric acid to remove the rust on the spoke ends, and to my surprise, it cleaned the rim up really well.

It will need to be polished again, but all the crud and corrosion has gone, so it'll be a piece of cake without all the crud to deal with. Of course, Borrani rims are good quality aluminum whereas our carbs are crap quality "pot metal", so they'd probably dissolve in the acid. I've got a few old sets of carbs sitting in my garage though, so I might try one, just for fun. Cheers, Terry.    

[greenjeans]

If you have an air compressor, I'd make yourself a home made soda blaster.    Quick, easy, best of all it's cheap and it really works quite well.

http://forums.sohc4.net/index.php?topic=5410.msg517431#msg517431        bout halfway down.

After you clean all the passages etc, hit them with the soda blaster.   I then boiled them in plain water for 5 minutes or so to get rid of the baking soda and checked that the passages were clear again.

They look new again.

[lucky]

I think you should stay away from chemicals. You can discolor the aluminum.

You could also ruin the throttle shaft seals.

[Magpie]

A day's soak in Pine Sol worked well for my carbs. It works well on aluminium, not good for steel, without discolouring the bodies like soaking in Simple Green can do. I took all the plastic and rubber parts off but other just toss the whole carbs in a bath and rinse well. Cliff.

[stereosilence]

I am currently doing the simple green method. The outside of my carbs have a lot of dirt. The best thing to do seems to be to scrub them all over with simple green and a tooth brush to loosen dirt, then soak them for about an hour, then scrub again, and if it doesn't need to soak longer, I spray with the hose (with some pressure) and then rinse the water off with some carb cleaner to prevent any rust.

It seems to be working well. I think the soda blaster is the way to go if you can.

[GK]

I put mine in my ultrasonic ebay cleaner, brought them up a treat, then soda blasted them to bring them up to the original aluminium finish , will be posting pics in my build thread tomorrow

[Trevor.resar]

http://forums.sohc4.net/index.php?topic=101675.0

Carbs took some time, but turned out really well

[lucky]

I've got a Borrani rimmed CB750 rear wheel that I need to re-spoke and re-hub. The tire is off it, but the ends of the spokes were really rusty so I couldn't unscrew the spoke nipples. I dunked the rim in a tub of phosphoric acid to remove the rust on the spoke ends, and to my surprise, it cleaned the rim up really well.

It will need to be polished again, but all the crud and corrosion has gone, so it'll be a piece of cake without all the crud to deal with. Of course, Borrani rims are good quality aluminum whereas our carbs are crap quality "pot metal", so they'd probably dissolve in the acid. I've got a few old sets of carbs sitting in my garage though, so I might try one, just for fun. Cheers, Terry.

Please do not ruin a spare set of carbs!!! There are few left and thats it.
Every carb part is valuable.

Also the acid can ruin the throttle shaft seals in the 77-78's.

[peaches67rs]

Thanks, everyone. I appreciate all your help.