Motorcycle carbs with brass inserts

[fothers New User Find all posts View Profile Close fothers]

Hi All from the UK.

I want to end up with a nickle (or maybe copy chrome) plate on the carbs from my 1976 Honda CB550F2. The bodies are in good condition (no pitting) but look a dull bluish-grey colour and are non-magnetic so I guess they are pot metal (I haven't done an acid test yet). They also have small brass plugs which are non-removable (but I guess these will just be plated over unless I mask them?).

I know that I will have to strip the carbs and polish them before I do anything and I know that flash copper would probably be best for providing a strike coat but the carb bodies are hollow, irregular and complex in shape and it will be really hard to get an anode down the inside of the slider body... so here are my questions:

If I don't get coverage inside the slider chamber, the fuel ways and holes where the jets were, and I then go on to plate; won't the exposed zinc corrode and contaminate my regular nickel or copy chrome bath - not to mention wreck the part?

Would I be better off with the pot metal electroless nickel kit rather than flash copper for a strike coat prior to regular nickel plating of copy chrome plating in this case?

Thanks to all those who have contributed to the forums, your info has given me the incentive to get started (you just need to keep me going now!).

Cheers,
Pete.

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: Motorcycle carbs with brass inserts

My guess would be that the carbs. are aluminum, and you would need a Nitric acid bath to do that type of metal. Do your acid test to make sure what type of metal it is and then go from that. THe flash copper will work good for the first step and you shouldn't have to worry about the inside to much cause you don't want to plate more that about 10 minutes. YOu sure don't want any plating getting into the jet ports and the slide port due to the proper operation of the carb. So just plate 10 min. in the flash and 15 min. in the nickle.

[fxstcguy98 Amateur Metal Finisher Find all posts View Profile Close fxstcguy98]

Re: Motorcycle carbs with brass inserts

I would think it is alum too. I wouldn't plate it for two reasons, if you get plating into the jet holes, it will ruin it, secondly, those have alot of chambers and holes in the body that will make rinsing very difficult and will cause a lot of drag in to your solutions. I would just polish it up real good and zoop seal it, it will look pretty cool with the brass and the alum polished.

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: Motorcycle carbs with brass inserts

I agree it will be alot easier.... You might want to try a tumbler to polish with and make sure you blow out all the holes before reinstalling it.

[fothers New User Find all posts View Profile Close fothers]

Re: Motorcycle carbs with brass inserts

Thanks Guys,

I put a drop of battery acid on an area that doesn't show and got bubbling. I tried it on one of the carb caps that I know is aluminium and got no reaction. What next, do you think?

Cheers,
Pete.

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: Motorcycle carbs with brass inserts

It realy depends on how bad you want the carbs to shine. Its pot metal and pot metal can be plated but man it could be trouble after the plating is done the bike might look good but run good I don't know. Try polishing carb out very good before plating so you don't have to plate very long. Ten min. would be the longest I would plate due to any kind of build up, and no acid copper just 5 min. flash copper and 5 min. nickle maybe 10 min. nickle then chrome. You can take a hot glue gun and glue over the holes and this will help, make sure you put alot around the hole, and do this after the part is degreased and clean then glue the holes. Don't worry the glue will pull out easy thats why I said alot of glue around the hole.

[fothers New User Find all posts View Profile Close fothers]

Re: Motorcycle carbs with brass inserts

Thanks fly.

What if I polish the carbs and glue the brass and holes, and then went for the pot metal electroless nickel treatment?

That would give me an overall nickel strike coat (including the inside), right? Wouldn't that then do away with any worries over drag and contamination and I wouldn't have to worry about acid and plating times after that - or would I be making life hard for myself?

Cheers,
Pete.

[fly Amateur Metal Finisher Find all posts View Profile Close fly]

Re: Motorcycle carbs with brass inserts

Im not sure about the electroless nickle, I don't use that chemical but its worth a try as long as you keep the holes covered it (should) work.