Vintage Dirt Bike Q & A

Can anyone reccomend the best method of cosmetically restoring a carburetor. I am about 90% done restoring my 1974 Honda CR 125 and the carburettor which I rebuilt still looks like crud! I have tried carb cleaner, soft wire brush, rubbing compound, etc. and it still looks bad. I have seen some real nice show quality bikes where the carbs look like new. I did see a company online that offered "sonic" cleaning for $60.00. might be worth it for top notch results. I figured media blasting would be out for obvious reasons. Any suggestions are appreciated. Thanks.

I got two done in a sonic cleaner with just dawn dish soap and water they came out looking real nice. Some people use chemicals and they probably work better my friend is just cheap and it works well enough. He charges 50 a piece.

It's a dangerous gambit but you could try media blasting. I have a sandblast box and one of those little hand held ones from Harbor Freight for stuff that doesn't fit in the box. They use a lot of aie so if you don't have a good compressor it's a mute point.

Thinking about it, it would be better to use something soluble in water like sodium bicarbonate or table salt on a carburetor. I think I will give it a try. Sand/aluminum oxide scares me because I worry about plugging orifices with something I can't get out.

Rick

I have restored a couple of carbs with acceptable results. Depending on the condition
of the carb body, you can get good results with an ultrasonic parts washer and an
aluminum specific cleaner. If the finish is oxidized and all but corroded, try an aluminum
brightner from Casswell http://www.caswellplating.com/aids/albrite.html

If the finish is really bad, I use glass beads or walnut shells in a blast cabinet at 35-40
psi. You have to be really careful blasting, sanding, wire wheeling, etc. because the
carb bodies are anodized and all the above can and will remove the protective finish
making the problem worse and much more expensive to make right. Once you are done
blasting, lightly go over the components with a 0000 steel wool to smooth the finish
then thouroughly clean everything before reassembly.

In addition to a complete rebuild, I also remove all the external brass and polish off
the oxidation.

My advice is to start with the least aggresive (ultrasonic wash) and work your way
up until you get the desired results.

I am posting some pics of the two carbs I have done. The first one is from my '73 and
only required an ultrasonic cleaning, brass polish and rebuild. The second one is from
my '79. This carb was a mess externally with pitting and corrosion and somebody had
tried to clean the body with a corrosive cleaner that left parts of it black. It required
glass bead blasting, steal wool, ultrasonic cleaning, brass polish and rebuild.

dogger



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_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Thanks for the tips. I think the media blasting is out mostly because of the cost of the equipment. I have been looking at ultrasonic cleaners thinking it would pay for itself after 3-4 carb cleanings. My real concern was how well they work. Dogger, the carbs you restored are the results I am hoping to achieve. Did you send either of them out, or do them yourself. If so what type / brand of ultrasonic machine did you use. I checked online and prices are all over the place. I am thinking that a unit around $300.00 would suit my needs and budget? I am attaching a picture of what my carb looks like now. Will post an after shot if I achieve the desired results. Thanks again.

Sorry about picture size. I will try to post better ones in the future!

That carb isnt horible I think an ultrasonic bath would clean it real nice. Be carefull when choosing a cleaner tho you dont want a cheap unit thats gonna break or may not work well. My friend paid 700 for his and its not very big two carbs will fit if they are small. Cant remember the brand but will let you know if I talk to him today. Oh and dont use cream of tarter in it he tried it and it turned a carb black.

PACDESIGN, I do all my carb work myself. I tried sending a carb out for restoration a while back
and it didn't meet my standards when it was returned. The body had been media blasted right through
the anodization and was ruined. I had to pick up another carb and start over.

I use a Crest parts washer (I've posted a pic of it below), that is big enough (8 gal) to handle parts
like fork legs and engine cases. I use lots of different cleaners. For steel parts like tranny gears,
etc., I use Royal Purple parts wash mixed with distilled water. For aluminum parts I use Bransons
MC3 cleaner http://www.sonicsonline.com/mc3-metal-cleaner.html I have also used various Crest
chemicals as well as straight soap and water. The trick is using the right cleaner with the right
amount of heat for the correct amount of time.

In my opinion, there are three good reliable brands of sonic cleaners: Branson, L&R and Crest. I'm sure
there are other good ones as well. Just remember, like everything else, you get what you pay for

If you want a test run before investing in a unit for yourself, disassemble your carb and send me the body
(cap, upper and bowl) and I will sonically clean it using the MC3 and send it back. Don't worry about any
brass left on the body because it will clean that up as well. If you are going to restore other bikes, a
good sonic cleaner is a real handy tool to have.

dogger

[img][/img]

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

By all means go with ultrasonic or whatever is the least destructive means available for the first go round.

I do want to point out media blasting isn't that expensive though. You can pick up a self contained gun for ~$15 that works. The main problem is air supply. I have something like 5hp 24 gallon compressor and it just barely keeps up with my sandblast box or the portable gun. I mainly bought the gun for stuff that wouldn't fit in the box. You could get by with one of those $70 pancake compressors but I imagine it could take all day to do a carburetor.

Rick

Hey Dogger,
I will gladly send the carb to you if it's not too much trouble. I am pretty sure I will purchase an ultrasonic cleaner. Im just not sure what size. Price is definately a factor but I want to get one bigger than I think I need. Let me know where to send the carb and I will mail it off. Rick, as for the media blasting, I would give it a try but my compressor is a 30 gallon, 3-hp unit and I always assumed that was not enough for blasting? Any way, thanks to everyone for the help. Very informative.

Scott

Rick is so right about air supply. When I first started media blasting, I used a Craftsman 4 hp 30 gal compressor
that ran so much it would overheat. You just about have to have a continuous duty compressor with a jumbo
tank. I finally broke down and picked up a monstor Quincy unit with a two stage compressor, an intercooler and
an aftercooler that weighs 700 lbs. - No more air problems.

Media cabinets and sanders are some of the biggest "air eaters" out there and the average weekend warrior
compressor just won't cut it. But I have also found that farming your blasting out gets expensive in a hurry.
In fact, I have found that farming anything out gets expensive in a hurry and more times than not, the results
are disapointing and don't justify the cost. So I keep "investing" in more equipment so I can do everything
in house. That way if I am disappointed in the results, I can only blame myself.

Scott, I pm'd my info to you.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Sorry for the delay in posting the before and after pictures. Thanks again Dogger for cleaning my carb. As you can see it looks great. Thanks to everyone for the great advice. I will definately be investing in an ultrasonic cleaning machine in the next few weeks.

Scott

Looks like you are doing a first rate restoration. The motor looks great.
Post some pics when you're done, can't wait to see how the rest of it
turns out.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R