Reinstalling the carbs on my 76 XS650.

Zonie

Zonie

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Been working on my 76 XS and did a complete carb cleaning. The bike sat for several years prior to my getting it.
Now that I have done all that I am having issues getting them back on. I have new manifold rubbers and so I am thinking that things are a bit stiff.
I did lube up the manifolds with silicone grease, but they just don't want to go on.
Ideas or suggestions.
Thanks for your help in advance.
 
will you be supporting the carbs with the original airbox?
If not, I recommend lubing the carbs with a soap/water lube which will evaporate.
Silicone grease or other and no rear support would leave your carbs vulnerable to falling out of position in the manifolds.
Been there done that
 
I got the manifolds from Mikes XS, so I assume they are the correct ones for my bike. I am using the original airbox but thank you for the tip.
Going to clean the petcocks next and see if there are any surprises in the tank. I started on this project about 18 months ago and got sidetracked by a Norton Dominator. That project is almost finished and so I got the XS out and started to sort it out.
 
I don’t recommend it but you can use a long pry bar or a wooden block to put pressure on the carbs pushing against the down tube of the frame. Again, if you do that be very, very careful. Otherwise with good lube and working them up and down with pressure and they will eventually go.
 
It's possible to reach one arm around the front of the motor so you can pull both carbs forward against the manifolds with strength. You can also use a stick against the rear down tube for leverage. During an overhaul I typically take a fine file and lightly round off the the outer front edge of the carb body, intake horn, it really eases insertion. The casting is often a bit sharp edged/rough there.
Like Jim sez double check they are right, smit happens in order picking.
 
Been looking at the manifolds listed on Mikes XS and they are sided. No mention of this in the Haynes manual. There is a R & L cast into the manifolds, and I had them on the correct side. Then I noticed a notch on the manifolds which corresponds to the carbs. So, now I know which side is up and which side of the bike they go on. With that piece of information, I can correctly mount the manifolds. Progress is being made.
Thanks for your help.
John in Texas
 
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XSTime said:
will you be supporting the carbs with the original airbox?
If not, I recommend lubing the carbs with a soap/water lube which will evaporate.
Silicone grease or other and no rear support would leave your carbs vulnerable to falling out of position in the manifolds.
Been there done that
Click to expand...

To add to that, some years ago there was a post regarding fabbing a hanger of sorts coming off the backbone to support the carbs sans an airbox. Thinking about it, that would keep them in place vertically. Might not help on a nasty backfire........
I crank the dogshirt out of the clamps to where she won't turn no more. So far, so good.
 
Zonie said:
Been looking at the manifolds listed on Mikes XS and they are sided. No mention of this in the Haynes manual. There is a R & L cast into the manifolds, and I had them on the correct side. Then I noticed a notch on the manifolds which corresponds to the carbs. So, now I know which side is up and which side of the bike they go on. With that piece of information, I can correctly mount the manifolds. Progress is being made.
Thanks for your help.
John in Texas
Click to expand...
Interesting. Knowing that the notch had to be at the top I went to install them, and it wasn't right. Looking at how the notch is orientated to how the manifold sits was wrong. So, I swapped them, and everything lined up. But the R manifold was on the L and the L was on the R. I assume that right and left are from when you are sitting on the bike. I also had the top X shaped bracket on backwards. The deeper part of the X faces the rear.
Need to warm up the manifolds with my heat gun and give it a go.
 
You got it !
When my BS38’s “fell off” years ago on a ride 100 miles from home it was a real surprise!
A Speed bump ! A jolt from a high speed speed bump hit and the carbs actually came off.
So, soapy water to install! You do not have to overtighten the clamps, they bend.
 
I've never had any issues getting the carbs in or out. I put the bike on the centerstand, straddle it and grip the sides with my legs so I don't push it off the stand, then rock the carb set up and down as I push it in. I lube the manifolds and the carb stubs. I used to use a little white lithium grease, now I use red rubber grease. For removal, I have to use a spray lube like WD40. The rocking motion is what does the trick, for both removal and install.

I replace the Phillips screws in the clamps with Allens, and I make them very tight. I tighten the clamps fully until the two halves touch. I've run pods since I've had the bike (near 20 years) and never had the carbs fall out. Yes, I have had the occasional backfire on start-up blow them out, but they never just fell out on their own. And I recommend original clamps as well. The ones from MikesXS are junk, skinnier and they have smaller screws. They don't hold as well.
 
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I fought with carbs before until I found the pry bar against the downtube trick. Now they go in easily, albeit with newer, supple carb boots and some silicone lube. Use some thin sheeting to protect the paint.

I used to torque the the hell out of everything until I realized I had cut through the inlet rubbers on my Uni filters. Now it's just tight enough to keep them from moving and that's it.
 
With the help of a friend the carbs are mounted, and two of us made the job easier.
Just dumped in some Evaporust into the tank and I will let it sit overnight. Not a lot of rust in the tank but as long as I'm in there might as well.
 

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