Cleaning Carbs/Tank Removal

[EHLawyer]

I'm getting ready to clean the carbs on a 79 xs 1100 special........read all the tips and posts about it here, and am wondering what it means to clean the carbs "on" or "off" the rack.........I'm assuming that you can clean each carburetor without disassembling it from the other three......Is that what is meant by "on the rack"? If not, let me know. Also, when removing the fuel tank, is it necessary to remove all the fuel? I think I'm supposed to turn petcocks to on or reserve and then pull the fuel lines from them.........what keeps the fuel from running out?

Thanks for answering all stupid questions.

[randy]

Yes, "on the rack" means not taking the bank of carbs off of the rails. When you clean them this way, don't submerge them in carb cleaner or you'll dissolve the throttle rod seals. All of the other rubber parts are removable without taking them "off the rack".

You can do a complete cleaning on the rack.

As for the tank, turning the fuel taps to ON will hold the fuel in the tank IF your fuel taps are working properly. In normal operation, the fuel taps will only flow fuel in the ON position while the engine is running and vacuum is applied to the tap vacuum nipple.

In some cases, your taps may need re-building and they will leak in the ON position. You will surely know if your taps need re-building when you pull the fuel lines!

Have fun. A successful carb clean can be very gratifying.

P.S. there is no such thing as 'triple clean' if you do it right the first time. Follow the tech tips and you can't go wrong. If you hit a snag, post it!

[TopCatGr58]

Hey EHLawyer, and Randy,

Turn the petcocks to OFF....Specials have that setting, along with Prime, Reserve, and ON. The Octopus is the vacuum contolled valve....not the petcocks!

I just finished a set of 79SF carbs, another part that you can't remove UNLESS you pull them OFF THE RACK is the choke/fuel enrichener plunger. Also, the rubber coated "T's" can't be removed unless you at least take the outer carbs off!

But taking them OFF THE RACK isn't so bad really, leave at least one of the 2 center ones on the rack. The part that joins each carb for opening the butterflies is a simple spring loaded plunger and adjusting screw, you can slide the carbs apart, then when putting them back together, just pull on the spring plunger to open the gap where the metal flange fits, you don't have to turn the synch adjusting screws, so less likely to loose your synch setting. Just take is slow, and you'll do great!
T.C.

[Ken Talbot]

Be forewarned, though, that removing the carbs from the rack will require the use of an impact driver to break loose the loc-tite that was used to assemble the racks. If you start without an impact driver, you WILL have slippage and strip the head on one of more of those $#%^ phillips head screws. If you take the rack apart, seriously consider replacing the phillps screws with allen head screws.

[TopCatGr58]

Hey Ken,

With the Allen Head replacement bolts, is locktite really necessary to put them back together? I didn't use any on my 81SH(holding for 4 years now), and I went back with the OEM screws. Just wondering if I should bother putting locktite on my newly rebuilt 79SF carbs!? I seemed to be able to get the allen head bolts pretty snug!
T.C.

[Ken Talbot]

I used blue loctite whan I reassembled my bank'o'carbs but I don't know if I could come up with a real good reason why.


Loctite is a must for the screws in the butterflies because that's the last place you want a screw coming loose. I suppose a loose screw or three on the rack could allow a carb to move around a little bit, but I think it would have to be pretty bad to throw off the carb sync.

[GNEPIG]

.. i have taken the carbs off the bikes and found some of those screws loose and missing, a little dab of blue loctite is worth it for the peace of mind
there is a large amount of air moving through these carbs, i can see how they could have a little flex .. other than the beems holding them together they mostly float in rubber