Topic: Buying old carbs!

[KrautKoffin]

So the PO buggered up my carbs pretty badly, the carb bodies appear to be warped and the threads that hold the bowls on are stripped out. I took them to a mechanic to rebuild and he confirmed this, so I need to replace them. I found a set on eBay for $90 for my k7, but is there any thing I should be wary of? I have full rebuild kits with needles, floats, ect. Bike is a 1977 cb750k.

Any help is appreciated!

[750K]

Well it's always a crap shoot buying something you can't hold in your hand first, at least youve got a screwed up set as a parts back up if anything is damaged.

[harisuluv]

Just get the right set for your bike. Identical casting numbers not mandatory but can make things easier. if you dont see pictures of the inside of the bowls assume they are being hidden for a reason. ask if they are stuck or not. Ask questions.

Do you have a pic of these warped bodies?

[KrautKoffin]

I don't have pics but I will get them this weekend when I get back over to my bike. I didn't get a picture of the bowls, this is a crap shoot I don't like being in.  These are the carbs I bought to replace mine. Super cheap which kind of scares me but I think they are just cheap because they sat for so long:
http://www.ebay.com/itm/251344049741?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

[bjbuchanan]

So the PO buggered up my carbs pretty badly, the carb bodies appear to be warped and the threads that hold the bowls on are stripped out. I took them to a mechanic to rebuild and he confirmed this, so I need to replace them. I found a set on eBay for $90 for my k7, but is there any thing I should be wary of? I have full rebuild kits with needles, floats, ect. Bike is a 1977 cb750k.

Any help is appreciated!

I'm not doubting you/your mechanic but what is warped, what makes the carbs shot? Most mechanics would rather just R&R, it is economical for them and much easier. Dirty funky carbs aren't necessarily bad tho, just need work. Eroded main jet towers, broken float pics, obviously badly broken external stuff is the real major stuff. You can fix those carb screw holes and can clean the carbs yourself much better than you probably think you can

Either way, now you know what to inspect on your new carbs, and as mentioned you will have plenty of spares which can be handy.

[harisuluv]

Well, I wish you would have taken my advice. That listing just has two pictures and doesn't show the bowl insides.  If he unscrewed the bowls and they were decently clean he could get maybe almost double the asking price.

Makes you wonder why he didn't show you that....

Either way let us know how they look, we will help you

[KrautKoffin]

Thanks guys, I'll post here as soon as I get them!

[GoldWingWiz]

Having Just re-built 4 Carbs on my '83 Aspencade with my Vintage Honda Biker Buddy (and he shouldered the brunt of the detailed work):

1- I would make sure the re-build kit & or parts you use are very high quality; there is a lot of "inferior" aftermarket stuff out there (for that reason, we only use Randaak re-build kits for Gold Wing Carbs, they are superior to even OEM Honda!)

(By the Way, Randall Washington (that's Randaak) is speaking at the Barber Vintage Festival this year! It's over Columbus Day weekend at Barber Motor Speedway just outside Birmingham, AL, and is possibly the country's BEST Vintage Bike Event.  The Vintage Japanese Motorcycle Club has a strong presence and you can park at their booth by the front gate, as well as ride a Parade Lap on the Racetrack for free,  if you are a VJMC Member.  My '83 Aspencade plans to be in the show at the Motorcycle Classics Tent; please Vote for me if you are there!)

2- Be prepared to remove Rust & Gas Gunk & Varnish from every part that stays original on the Carbs.  ONLY use SeaFoam or Techron for this, NEVER use the strong & deadly Car Carburetor Cleaners on a Bike Carb because it will destroy the useful life of any delicate felt or rubber rings & other parts that Mother Honda chose to put in your Carb.

3- When the Carbs are re-built & synchronized, be sure to keep them clean by using an ethanol fighter like Star-Tron or the Liquid Performance additive.  Never use Stabil, since it has a Diesel Fuel base & over time that will decompose your fuel lines.  (I don't trust Marvel Mystery Oil for that reason; unless they come clean with what their "secret formula" is, I would not put it in a Bike's Gas Tank.)  In any case, ethanol will be the death of us all, and our Bike's Fuel Systems!

Good Luck with your Carb re-builds. Remember, when things get tough & frustrating; that's what builds character!

[Elan]

how on earth would a carb get warped? Running it over with the right weight car? I would think it would crack before warping.

[Bankerdanny]

Never buy carbs where the seller won't send pictures of the float towers.

[KrautKoffin]

how on earth would a carb get warped? Running it over with the right weight car? I would think it would crack before warping.

No idea, I just couldn't get them to stop leaking, being the first time I have messed with bike carbs I took it to a mechanic. I'm used to carbs on cars, so I took his advice.

[lucky]

how on earth would a carb get warped? Running it over with the right weight car? I would think it would crack before warping.

Ridiculous! You better get a different mechanic.

If I did find a "warped" carb body I would show the owner how it is warped .
Also if it warped it would probably be cracked.

[Irukandji]

  Warped as in trying to mount carbs with as has been suggested a come-a-long??

[KrautKoffin]

I think he meant the carb body to the bowls

[750K]

I find it hard to believe that, maybe the bowls could be out but the gasket should take up any differance. Something major would have to happen to warp the body, your leaking might be from a different issue and you can re tap the bowl screw threads. I have tapped out half the threads on the PD41a's that were on my 77.

[crazypj]

I'm not doubting you/your mechanic but what is warped, what makes the carbs shot? Most mechanics would rather just R&R

  That isn't a mechanic, that's a fitter (parts replacer)
 In the US you have various classifications for trained/experienced 'blue collar' workers, in UK it was generally
1. customer - know nothing not interested in doing any work
2. bodger - doesn't have any tools but is going to 'have a go'
3. enthusiast - can do servicing and maybe rebuild but doesn't really know or understand why
4. Apprentice - going to learn something from more experienced people who may or may not know why things work
5. Fitter - can fit parts after someone else does diagnosis
6. Mechanic - has real good understanding of how mechanical systems work, can figure out problems
7. Technician - can explain why things work plus do everything previously listed
8. big headed know it all - me 

Hope no one takes list too seriously 

[KrautKoffin]

I find it hard to believe that, maybe the bowls could be out but the gasket should take up any differance. Something major would have to happen to warp the body, your leaking might be from a different issue and you can re tap the bowl screw threads. I have tapped out half the threads on the PD41a's that were on my 77.

Even with new threads they leaked on me. I don't know what caused the warping but they were warped. Mechanic may have decked the surface, I don't know. I haven't been over there in a week.

[750K]

Where is the leak from? Do you have the float levels set to spec and float needles in good or new shape?

[KrautKoffin]

Where is the leak from? Do you have the float levels set to spec and float needles in good or new shape?

Floats set, new needles, it was leaking at carb 1 and 3 between the bowls and bodies.

Update: the carbs are 42 series, my old ones are 41 series. Do all of the internals swap over?

[750K]

Yes all the 41's parts can swap into the 42's, I just swapped everything from a set of 41's into a set of 42 bodies.

[lucky]

  Warped as in trying to mount carbs with as has been suggested a come-a-long??

Yes....that was a crazy idea. Never had that much trouble! wow.

[lucky]

Where is the leak from? Do you have the float levels set to spec and float needles in good or new shape?

Floats set, new needles, it was leaking at carb 1 and 3 between the bowls and bodies.

Update: the carbs are 42 series, my old ones are 41 series. Do all of the internals swap over?

IF the float bowls were leaking between the body and the bowl there is only 4 things that would cause that problem.

1. Float level incorrectly set (very common) Just read your manual.
2. Float needle and seat needs to be replaced. (not polished with tooth paste.)LOL
3. Float bowl O ring needs replacement (rare).
4. Float bowl drain clogged?

[lucky]

So the PO buggered up my carbs pretty badly, the carb bodies appear to be warped and the threads that hold the bowls on are stripped out. I took them to a mechanic to rebuild and he confirmed this, so I need to replace them. I found a set on eBay for $90 for my k7, but is there any thing I should be wary of? I have full rebuild kits with needles, floats, ect. Bike is a 1977 cb750k.

Any help is appreciated!

You MUST remove the pressed in idle jet and make
 sure you can see daylight through it.

Do not think you can use a paper clip on it, You will ruin it.

You will need a .010 thousandths guitar string from an electric guitar.

The stock idle jet is about .013 thousandths.

[KrautKoffin]

Pulled bowls 1 and 3, threads look good, PO left gas in them obviously.. 

[Elan]

Those don't look bad. THey will clean right up. THe big thing too look out for is corrosion. I have some carbs where the column holding the jet had disintegrated! I opened the bowl and it looked like someone was stashing some white powder in there