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1982 Yamaha 750 carbs open for rebuild. Float bowl gaskets fused to the rims of the carb, not the bowl itself, so the rim around them and the internal bosses prevent a razor from getting at them. Really fused to the aluminum! My dental pick can't get under them, but just takes off tiny bits at a time. I can't think of a way to clean them off without spending an eternity nit-picking at them. This has got to be something that has confronted every restorer. What's the best approach? Thanks
 

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I'm not familiar with your particular carburetor, but in general if I'm cleaning off an aluminum mating surface I'll use an angle air die grinder with a fine Roloc nylon disk. I'll use a medium if it's a heavy gasket and there's a lot of crud to get off, then finish up the surface with the fine.

If it's a rubber ring type gasket that's recessed in a groove I use a brass wire bristle brush.

Depending on what the gasket id made of, throwing some carburetor cleaner or Brake Klean at it can help too.
 

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I'm not familiar with your particular carburetor, but in general if I'm cleaning off an aluminum mating surface I'll use an angle air die grinder with a fine Roloc nylon disk. I'll use a medium if it's a heavy gasket and there's a lot of crud to get off, then finish up the surface with the fine.

If it's a rubber ring type gasket that's recessed in a groove I use a brass wire bristle brush.

Depending on what the gasket id made of, throwing some carburetor cleaner or Brake Klean at it can help too.
Thank you! I'm off to try it...
 

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Stuck

We will either find a way, or make a way. Hannibal I think.
This is a problem if you want to get the bike running again, and you do not have a new gasket. So it is decision time. Rip it apart and you will not be riding for a while. Put it back together, order some parts, and try again when the parts arrive. If you are really lucky, you will rip the old gasket, and the new one will not fit.

All four on my 1980 XS1100 came apart with no problem, same with the two on my XS400. I put a light smear of grease on things like that when I put the together. Actually I put some grease on most every bolt and screw.

Unkle Crusty*
 

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Hey I broke the first three carb bowls I tried to get off.
I decided to try the soak method and frankly, there isn't much that can withstand an overnight soak in a sealed gasoline container. I finally found that with WD40- internittent with digging, scraping, and an occasional cuss, I can usually coax a bowl off using light suitable prying pressures and a couple xacto-blades.
but if its just the gaskets, get a fire, lighter, candle, and light those suckers up man!
 

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Berryman's Carb Cleaner

Berryman's made that a lot easier to get mine out from a 1974 Honda. Same situation as you, just little bitty chunks coming off. Berryman's has more of the good stuff like MEK in there, so use in a well ventilated area. After using it, a razor knife got most of it off and a piece of #12 stranded copper wire cleaned out the remaining bits out of the groove.
 

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Before you go all primeval on 'em what about boiling them for a half hour to soften up the gasket material. I'd start with just hot water.

I had to clean big aluminum chunks permeated with grease, part of a meat slicer for our soup kitchen. Nothing worked except boiling individual pieces in lye. But you're after a gasket, not grease...

If water/lye doesn't work then an overnight soak in Berrymans or some other hydrocarbon solvent.

Scarring up, damaging the mating surfaces so a new gasket CAN'T seal is what you don't want to do. Hence a BRASS brush or COPPER wire rather than steel.
 

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Discussion Starter #8
Berryman's made that a lot easier to get mine out from a 1974 Honda. Same situation as you, just little bitty chunks coming off. Berryman's has more of the good stuff like MEK in there, so use in a well ventilated area. After using it, a razor knife got most of it off and a piece of #12 stranded copper wire cleaned out the remaining bits out of the groove.
Looking at Berryman's website, I see one product called chem-dip. Is that the one you used?
 

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Discussion Starter #9
Before you go all primeval on 'em what about boiling them for a half hour to soften up the gasket material. I'd start with just hot water.

I had to clean big aluminum chunks permeated with grease, part of a meat slicer for our soup kitchen. Nothing worked except boiling individual pieces in lye. But you're after a gasket, not grease...

If water/lye doesn't work then an overnight soak in Berrymans or some other hydrocarbon solvent.

Scarring up, damaging the mating surfaces so a new gasket CAN'T seal is what you don't want to do. Hence a BRASS brush or COPPER wire rather than steel.
OK. Boiling it. Worth a try. I tried a dremel tool with brass wire wheel last night -- no effect whatsoever.
 

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Hey I broke the first three carb bowls I tried to get off.
I decided to try the soak method and frankly, there isn't much that can withstand an overnight soak in a sealed gasoline container. I finally found that with WD40- internittent with digging, scraping, and an occasional cuss, I can usually coax a bowl off using light suitable prying pressures and a couple xacto-blades.
but if its just the gaskets, get a fire, lighter, candle, and light those suckers up man!
Carbs are completely disassembled. Bowls came away okay. Gaskets are fused to the top/carb part, not the bowls. I've got the bowl mating faces cleaned up, and new gaskets ready to install. It's the old gasket material--hardened and fused to the carb side--that does not want to budge. Nylon and brass wire wheels don't faze it. The gaskets are protected from razor blades by the wall/rim of aluminum that runs around the outside of them, and by the bosses and castings around the inside. I appreciate the advice, though. Never thought of burning them out of there!
 

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That "pot metal" that carbs are made from can be pretty crappy stuff and melt at fairly low temps so be DAMNED CAREFUL using a torch around it. There is also the danger of 'collateral damage' to seals and stuff in the carb body if it gets too hot.

What I do with stuff like that is to find a piece of scrap steel the right thickness and grind the end into a chisel shape or a J shape to scrape the old gasket off. You have to be VERY careful not to gouge the metal but those old hard gaskets can be impervious to just about anything else. Minor scratches can be sanded out.
 

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Discussion Starter #12
That "pot metal" that carbs are made from can be pretty crappy stuff and melt at fairly low temps so be DAMNED CAREFUL using a torch around it. There is also the danger of 'collateral damage' to seals and stuff in the carb body if it gets too hot.

What I do with stuff like that is to find a piece of scrap steel the right thickness and grind the end into a chisel shape or a J shape to scrape the old gasket off. You have to be VERY careful not to gouge the metal but those old hard gaskets can be impervious to just about anything else. Minor scratches can be sanded out.
That's exactly what I am doing now. I'm starting with those little jewellery -type screwdrivers as small chisels.
 

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Here is what I used [in an aerosol spray]
Once the thing got started, it came out pretty easily in 4 or 5 pieces instead of the little chunks as previously. Then spray a bit more and use the soft copper stranded wire in the groove. Gasket was probably original to the 1974 bike.
Oh, that one. I've seen it and used it like sea foam in the gas tank. I'll try it.
 

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Discussion Starter #15
Just to cap this off, I tried brake cleaner spray and those really small screwdrivers as chisels and with patience and some soothing North Indian classical music to calm the nerves got the old gasket broken up and scraped out. Thanks for the suggestions!
 

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Oh, oh. I said cap this off prematurely. In the little carb kits with all the jets and needles, there is a little silver puck. Does anyone know what it is and where it goes? I'm a newbie here so it won't let me post a picture. If you go to ebay and search for 82 Yamaha XV750 carb kit, you'll see the little silver puck in the picture. I can't find it on the exploded diagram for the carbs.
 

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Puck

I did not look at ebay. But if puck shape is a clue, some main jets have a puck shaped washer under them. Some kits do have bits that are not used.
Is there a hole in the puck?

I have the carbs apart on my XS1100 at the moment. They are probably very similar. Will look at them tomorrow. I am only cleaning and reassembling, not new parts. Bike has been sitting a long time, but is coming apart as if it were new. It is creepy clean.

Unkle Crusty*
 

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I did not look at ebay. But if puck shape is a clue, some main jets have a puck shaped washer under them. Some kits do have bits that are not used.
Is there a hole in the puck?

I have the carbs apart on my XS1100 at the moment. They are probably very similar. Will look at them tomorrow. I am only cleaning and reassembling, not new parts. Bike has been sitting a long time, but is coming apart as if it were new. It is creepy clean.

Unkle Crusty*
No hole in it. Nice little silver hockey puck.

These carbs are from Hell. Sitting for probably twenty years with old gas in them. Otherwise, bike is low miles and should be a nice runner when I get her going.
 
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