Age old carb questions

[JRcom]

Well, where to begin. I am the original owner od a 1978 XS1100E. I rode it faithfully for 10 years all over N. America. Then I bought another brand new bike and this one was kind of left for retirement. The plates on it are 1988. My XS11 has been setting under a Gazebo bike cover in my garage for 22 years believe it or not. Well I had a twang of nostalgia and pulled it out to modernize it and get it running again, sort of try at rekindling of my youth I guess. After about 2 hours some WD40, fresh motor oil, new plugs and battery, "Big B" fired and started, WOOOO WHOOOO!! Amazing after not running for 22 years. Well we pulled the carbs off to clean them and his buddy who is a professional mechanic by trade, came by and told us not to pull the top of the carbs off or we will ruin the old diaphragms under the caps. My contention is that the carbs will not get clean without doing so. If they are that fragile they will need replacement anyway. I purchased full rebuild kits that have the jets and springs included so why not use them? If I am taking this carbs apart to clean them I want to make sure they are totally clean all the way through and not a half way job. I have read almost everything on the forum there is to read about carbs and I am ready to go for it. Please advise, all opinions are appreciated. Oh, and I have a long way to go but to make "Big B" run good again is a great start. Thanks everyone for your great ideas and tips I have learned allot in just a week here.

[CatatonicBug]

Welcome to the forum! IMO, you are completely correct about removing the tops from the carbs. They have to come off to get the emulsion tubes out, and the diaphragms need to be flexible enough to flow up and down, so if they are going to break, you'd be better off having them brake while you are working on them than while you are travelling somewhere.

Be sure yo take some pictures so we can watch your restoration!

[cywelchjr]

+1 on the correctness. If the diaphragms are too fragile to remove the caps (which you MUST do to properly clean the carbs, particularly the emulsion tubes) then they are too fragile to operate. My XS400 which shares the same carbs, still had relatively good diaphragms in them, and I didn't know about plastidip for pinholes so I replaced them. They can be had brand new, and they work just fine, however, I haven't seen sitting causing a lot of damage, so they may well be just fine, but you really do need to pull them out and look them over carefully.

[prometheus578]

Ahhh... modification of the ol' "Schrödinger's cat" experiment, except using carb diaphragms.
Ya see... right now... The diaphragms are in both states of being, being both good and bad at the same time. You won't know if they're any good until you remove the cover.
Sort of the same as Schrodinger's cat. Didn't know if the cat sealed in the box was live or dead until he opened it up.
Now, suppose the cat was dead... when did it die?
ANSWER: It died the moment that Schrodinger opened the box and looked inside. (though it had actually died a week earlier)

Quantum Physics and Metaphysical Philosophy aside... I've never seen carb diaphragms ruined by opening the cover. Here's what you may find:
Diaphragm has pinholes in it. Diaphragm has a tear in it. Diaphragm has a section that has the rubber coating worn off of it, etc.

Now, as an extra bonus...
The diaphragm may have shrunk due to age and you'll have a hell o' a time getting it to stay in the groove when putting it back together.
The diaphragm could also have been gasoline soaked and expanded and again, you'll have a hell o' a time trying to cram the outer lip back into the groove when putting it all back together.

Fighting with carb diaphragms builds character, adds to your "mechanic's vocabulary" and is generally seen as a test of manhood.

Take the caps off and check to make sure the diaphragms are still good.
If'in the rubber has shrunk or expanded, some people us a little "silicone" to hold them in place during reassembly. Another trick would be to use two thin feeler gauges to hold the diaphragm lip in the groove. Place the cap back on top of this and slowly pull out the gauges.

[ManagerMike]

'Do, or do not; there is no try'

[DGXSER]

I'd have to agree that puling those caps, the slides and therefore the diaphrams is all but mandatory. When I got the project bike home and started into those carbs, at first I thought they did not look to bad. Then I started pulling the emulsion tubes out. And I found gas that had varnished up and crumbled and caked into a sandy looking dark brown goo. One of them I had to drive out with a hammer and a wooden dowel for all the gunk built up in there. All your cleaning effort will be for nought if you leave a mess like that uncovered.

As the others have pointed out, it won't just be the edges the cover holds sown that have problems, the entire diaphram will. One way to check them before hand is to push the slide up and put your finger or soemthing over the vacuum slot in the inlet bell of the carb. If the slide falls, with any noticable rate anyway, you have a leak you need to fix anyway.

[81xsproject]

Take them out and inspect them for holes. Then hose them down with silicon spray lube. Let the acetone in the spray evaporate and then throw them in a plastic bag while you clean the carbs. This will bring back lot flexibility. Do yourself a huge favor, and don't use anything in those kits except the bowl gaskets, and float valves. Give them a good cleaning (don't submerge the whole bodies into the dip cleaner unless the butterfly shaft seals have been removed. Blow them out with lots of compressed air (while dis-assembled). As for getting diaphrams back in, I just use many fingers to hold the lip in the groove for a couple minutes. After that, they will usually stay while I get the cap on. I have only had to use any kind of adhesive/sealant one time. I have cleaned and rebuilt dozens of these carbs, let me know if you have any questions.

[natemoen]

I put some baseline in the groove that the diaphragm sits in and that keeps it stuck in place so I can put the cover on.