Topic: Carburetor cleaning and overhaul

[Redline it]

Got some carbs the other day. Condition looks fairly decent. Orings are crumbly. Nothing is seized. Still has the air screw limiter caps on all 4 carbs. current I got 300$ into it. Any recommendations on plan of attack. Old school, or buy or make an ultra sonic cleaner? My usual style would be give it a good soaking in gas. Brush it a little and blow it off compressed air. Disassemble and store in numbered sandwich bags. Go as far as getting the slides out, but leave the slide adj's pretty much alone. Leave the carb body's together and soak again and blow out the passages. Reassemle and check for leaky carb connector fuel lines. And float level and bowl leaks. And run it. Or should I go 1 step at a time and report back for further advice.   

[ekpent]

Be helpful if you shared what kind of carbs you got. Sound like 350/400/500/550 or 77-78 750 if they have crumbly o-rings. Cleaning in straight gasoline would not be my first choice.

[Bodi]

Gasoline is rather too flamey for my taste to use as a cleaner. And it doesn't dissolve carb gum too well.
But your method should work OK to clean the bodies. I would use varsol  - or a hot aqueous cleaner (simple green?) but not leave them soaking in that too long as the alloy tends to turn a dark color. Acetone and MEK are also good cleaners, but also flamey and/or very poisonous or carcinogenic. Isopropyl is pretty safe but doesn't dissolve that gum much at all.
Cheap ultrasonic cleaners are pretty bad in my experience, and a good one costs too much for occasional carb cleaning. I got a Harbor Freight (actually Princess Auto, same thing but Canadian name) cleaner and exchanged it 3 times after they failed to work at all or failed after a short time, finally refunded it and gave up on it. A Branson or Crest is just too much $$$ for me.
I recommend pulling the bodies to replace the fuel crossover o-rings, and use Viton if you can find them. After all your cleaning, reassembly, and installation it will be a royal PITA to have to pull the rack out and apart for fuel dribbles from those tubes (voice of experience).
The vent crossovers use a small tube that's hard to find, I've been using model airplane silicon fuel line for them: these are not wetted with fuel and have lasted several years without issue for me.

[Redline it]

Be helpful if you shared what kind of carbs you got. Sound like 350/400/500/550 or 77-78 750 if they have crumbly o-rings. Cleaning in straight gasoline would not be my first choice.

400f 76 hopefully, i looked at one main jet it was 75 so i'm thinking they are, i didn't look for the stamp number, 54 or something like that? gas isn't my first choice either but solvent in the 60s and 70s is, it was excellent. gas is my second choice.

[Redline it]

Gasoline is rather too flamey for my taste to use as a cleaner. And it doesn't dissolve carb gum too well.
But your method should work OK to clean the bodies. I would use varsol  - or a hot aqueous cleaner (simple green?) but not leave them soaking in that too long as the alloy tends to turn a dark color. Acetone and MEK are also good cleaners, but also flamey and/or very poisonous or carcinogenic. Isopropyl is pretty safe but doesn't dissolve that gum much at all.
Cheap ultrasonic cleaners are pretty bad in my experience, and a good one costs too much for occasional carb cleaning. I got a Harbor Freight (actually Princess Auto, same thing but Canadian name) cleaner and exchanged it 3 times after they failed to work at all or failed after a short time, finally refunded it and gave up on it. A Branson or Crest is just too much $$$ for me.
I recommend pulling the bodies to replace the fuel crossover o-rings, and use Viton if you can find them. After all your cleaning, reassembly, and installation it will be a royal PITA to have to pull the rack out and apart for fuel dribbles from those tubes (voice of experience).
The vent crossovers use a small tube that's hard to find, I've been using model airplane silicon fuel line for them: these are not wetted with fuel and have lasted several years without issue for me.

 thanks bodi, i was afraid someone would recommend those crossover orings. so i better put them in. broke one of the vent tubes last time, maybe warm it up with hair dryer this time.  i'll can the ultrasonic idea. googled varsol, and now i know what it is and remembered i got a gallon of berrymans and a gallon of tyme (it was like 40 bucks a gallon. i chickened out on both of those, before on these carbs.) just found Crown PSC 1000 parts cleaner 5 gals for 44 bucks, i might check that out. i rethink the gasoline. thanks again.

[Deltarider]

Long time ago I have made inquiries about ultrasonic treatment. All three businesses I had contacted, explicitly informed me that they could not guarantee the results... Although curious, I myself have never felt the need to do it ultrasonic. My carbs have been used regularly, be it with 6 months intervals in winter. Keeping the carbs in a natural state - which is wet! - during winters have saved me a lot of trouble. On one or two occasions I have had them hibernate dry and it was not a success. As a result the next spring I had leakages. When I had opened a carb, I was shocked to see how much the seal had shrunk. Couldn't believe my eyes. No wonder they peed. Luckily after being in contact with gasoline again, they sealed well again. So far, after 44 years, the only seals I had to replace were those around the main jets and not even all of them. The O-rings at the T-joint seem to live forever. Looks like Honda did well to fit two on each side of that jointpiece. If you ever experience a leak here, I advise you to wait and see how things develop after the seals have been in contact with gas again. Give it some time and it's a good chance the problem will cure it self.
If you are afraid of keeping gasoline in your carbs during winter - I am not - you could add a fuel stabilizer or simply add the same amount of methylated spirits. Yes, I know it's alcohol. Does a great job absorbing water! Realise that these special products are also mainly alcohol...

[Mark1976]

   These carbs can be separated from the rack into pairs and then disassembled one at a time if need be. I'm never in a rush and rarely have enough time to do 4 carb bodies at one sitting,  so doing them one at a time and reassembling as I go is my preferred method.  But I assume a few things from the start, replace all the o-rings or buy new brass, the fuel line T fitting o-rings and the crossover tube o-rings all get replaced, or just get a quality rebuild kit. Buying the kit just takes the quess work out of trying to determine what is or isn't reusable.
   I've used the gallon of carb cleaning solution NAPA has sold for years with great results, just let each body soak for 2-4 hrs (after disassembling)and rinse in a hot soapy solution after followed by blowing out all the passageways with compressed air, then reassemble.
   I rarely disassemble the synchronizer assemblies, wipe or brush clean, re lube if needed. If there's no discernable play or wear, leave them alone. Less is better. By the time you get to the 4th carb body you're have the process of disassemble and reassemble down pat. Then slip them back onto the rack and reinstall.
   Then never use gas with ethanol in it, ethanol just mucks them up.

[Redline it]

the days of rational thinking are getting hit and misses. took a year to replace head and base gasket, surprisingly it worked and still running better and better. the carbs been leaking fuel for 10 months now pretty bad. and stop lights i'm shutting the gas off now. 10 months. i ride everyday. i'm surprised the carbs don't have stripped screws everywhere, i've taken em apart totally 30+ times in the last few years. so 15 minutes after sending neary 300 bucks to italy for anybody's guess on what i'll find (i'm always optimistic, and it doesn't help,) so the 15 minutes after figure i'll take a stab at it again, pull bowl #4 and notice the float  it' was a little high so i barely bend the tab and pull #3 bowl and couldn't stop the fuel so i knew either the orign or something was in the needle jet. but now i had to the bowls back on to take the rack  i pull the rack off took a few minutes, pulled the perfectly wedged piece of filter material out of the way of the needle took all the jets out except the needle jet, blew it out back and forth and sighted the floats adjusted each one just a hair. checked the fuel-clean, so i put fuel in it. no leaks. so washed the motor in gas to get the dark streaks all off. next day bike is no drips, yay. a week later i check the ign and in under 5 minutes got the pair of points almost dead on. no kidding the bike runs real nice, smooth, smoother than last week or 10 months. i've run this bike since the early 80s and i washed it 1 time couple years ago. it's always clean. i used a sand blaster nozzle with the tube in warm soapy water, took the chain off, it was clean, without drenches of water. it was a high pressure fog. i got an xr 500r i never washed it or wiped it, like a barbour jacket it builds protection, decided to clean it a couple years ago, well i just dug off at least 10lbs of oil packed dirt off the motor and swing arm. you know what, i'm gonna brush these carbs in gas and maybe some chem dip, rinse it and blow the holes out, and give the t fittings a chance to stay where they are. if the jet holders look packed then i might separate them, and then maybe put new orings on. all the jets are originals and they look like they've been taken off 1 time.

[HondaMan]

Stay with the original jets and needle jets, or they will be troubled.
I use lacquer thinner or xylene, and sometimes a small cup of gasoline for the small parts.