fitting airbox onto carb bank

[DaleE]

I searched for this topic but came up empty. Apologies if this is well-traveled ground.

Having owned a few Viragos in my day, I am already familiar with the cruelty and stupidity of Yamaha carb design. But last week I had an episode that made me want to put the bike out at the street for the trash. Over the winter I did a thorough cleaning and renewal of the carbs and cleaning/coating of the fuel tank. Since it's warmer now, I spent Saturday in the garage trying to put everything back together and see if she'll start. No joy.

I must have spent at least six hours trying to wrestle the carbs onto the boots, the airbox into its tiny space, and then the airbox onto the carbs. It was that last step that brought me to despair. So much so, in fact, that I nearly ordered pod filters, purely out of disgust. The rubber boots on the airbox seem to have become deformed, because they absolutely refuse to go where I tell them.

I'm looking to have another go at it in a few days. ANY tips or tricks that you folks might offer would be deeply appreciated.

[oldyam80sg]

The rubber manifolds are easier when they are warmed up- more pliable. You could use a heat gun on low.I removed my airbox shortly after buying the bike.

[Socer4m]

dont give up.....every xs1100 owner has swore like crazy at the carb design,,,,,,like oldyam said,,,use a hair dryer to soften the boots,,,,also smear some wd40 or vaseline on the inside of the boot and on the carb metal input.....also helps to wiggle one outer carb mostly in,,,then hold it and push the other side in. HEAT AND LUBE will make your life much easier. Pods are easy,,,but many have had issues with tuning. Keep us informed,,,,,welcome to the world of xs1100,,,Mike in San Diego and Pa.

[Radioguylogs]

Sounds like you got the carbs on the intake manifold boots.

To get the airbox boots on, I first look at each boot. I don't know if they were all the same when the bike was new, but the boots I have installed are not all the same. The two inner boots are relatively straight. The two outside boots are Z shaped because the airbox openings are spaced more closely than the carb openings.

So I put the airbox in place without the filter cover and without the filter,... but don't bolt it yet. Stuff the boots into the preferred locations with the clamps over the boots and complelety loosened. Then pull the airbox toward the carbs and wiggle the boots over the carbs as best you can. The wiggle the airbox and get the mounting screws to go in. Usually the boots resist getting the box on place to install the screws. It's OK to let the boots get out of place, and go a little too far into the airbox.

Then after you get the airbox mounting screws started, you can wiggle the boots into the correct posions and tighten it all up.

Believe me, it is soooooo much easier than my Honda V65.

[thumperjsa]

Keep in mind there are some tick marks on the boots for the airbox. Make sure they are in the upward position. They look like a little triangle. A hairdryer if you don't have a heat gun to soften up the rubber help as well as a little lube, like carb cleaner to help it on. Also, make sure the clamps are all the way loose and off of the slotted end where they are tightened. Another thing that can help is to shorten the snorkel. They don't need to go that far under the seat to work, but that's optional.

[Ccitis]

Mine must be pliable, I have had the carbs and airbox off tons and never had an issue... I would say mild heat and I spray some contact cleaner on there to lubricate if needed.

[motoman]

DaleE, for ease of those carb boots going onto carbs, heat those boots boots up a bit with a hair dryer then spray a bit of silicone lube to inside of boots and slip all that onto carbs with ease.

[DEEBS11]

Mike's comment about no filter and lid is very important. Also no clamps. Install those after everything is lined up.

[DEEBS11]

New flexible duct boots are also available.

https://www.ebay.com/itm/14530508889...Bk9SR7z1qPjPYw

[speedlimit85]

https://youtu.be/tsJ3xWA4V7g

[jkorn]

Always use the factory air box and don’t modify it. Otherwise you will loose low end torque. I tried individual air pods and that’s what happened.

[DEEBS11]

Hi Jeff, not sure if that is a factor but I pull a heavy sidecar with no airbox and have plenty of torque. Maybe it would be more with the airbox. But the bike can run great with no airbox. None of my 70's Japanese bikes have airboxes and they all run great. I still have the airbox and stock jets. Maybe I will try it someday to experiment.

[DiverRay]

The stock Yamaha exhaust system has a LOT to do with the low end torque. I've run stock and 4 into 1 systems, and the stock was always better at low end. Remember, when built, the '78 XS1100 was the fasted bike in a 1/4 mile. The engineers at Yamaha also worked on flow for Ford and other car companies.

[cajun31]

I searched for this topic but came up empty. Apologies if this is well-traveled ground.

Having owned a few Viragos in my day, I am already familiar with the cruelty and stupidity of Yamaha carb design. But last week I had an episode that made me want to put the bike out at the street for the trash. Over the winter I did a thorough cleaning and renewal of the carbs and cleaning/coating of the fuel tank. Since it's warmer now, I spent Saturday in the garage trying to put everything back together and see if she'll start. No joy.

I must have spent at least six hours trying to wrestle the carbs onto the boots, the airbox into its tiny space, and then the airbox onto the carbs. It was that last step that brought me to despair. So much so, in fact, that I nearly ordered pod filters, purely out of disgust. The rubber boots on the airbox seem to have become deformed, because they absolutely refuse to go where I tell them.

I'm looking to have another go at it in a few days. ANY tips or tricks that you folks might offer would be deeply appreciated.

If someone has had that airbox completely apart then the rubber parts may be misaligned. To verify, unless you know for sure, is to take the carbs and the airbox off the bike and align them properly. They can be rotated in place as well as interchanged from one location to the other. This is easier to do if they are pliable. Like others have said they are much easier to work with if heated up a bit to make them more pliable. Once you ensure they are lined up correctly they will be much easier to put on when the carbs are on the bike. I would not hesitate to buy a new set of rurbbers from Cruzin either. Those will make it a breeze. Of course you would be back to square one on getting them installed and aligned properly in the airbox. Keeping the oem airbox will make tuning the bike much easier than pods without having to worry about rejetting.

[oldyam80sg]

I been using individual air filters on my SG since I got the bike in 1986-never had an issue with them and the bike is rejetted with a 4 into 1 Kerker exhaust. Never had an issue with performance either.