Vacuum Hose routing

[Roadwarrior]

Hey, just came across this board on my search for information trying to get my 78 XS back up and running. The person I had picked it up from had taken the carbs and coils off and was going to use it as a parts bike. But it had been running before, and now im hoping to get it running again. Everything is looking good and I just finished getting the coils done and now im on to the vacuum lines. The repair manual I have doesn't seem to tell me where any of the lines go, so I was hoping someone here might be able to help me out. Basically no lines are hooked up right now so I need to figure out where they all go, and if any just get blocked off or anything.

[natemoen]

On a stock '78 you only have 3 vacuum lines. You have one line coming out of the back of the left side engine cover, that is the vacuum advance line. It gets connected to a small brass nipple that is on the #2 (second in from the left while sitting on the bike) carb BODY. Do not connect this line to one of the four nipples on the carb intake boots.

The only other 2 vacuum lines are for the fuel petcocks. Those lines are connected to the forward facing nipples on the back side of the petcocks and then are connected to any 2 of the carb intake boot nipples. It does not matter which 2 intake boot nipples you use, pick 2 and use them and just cap the other 2 boot nipples.

[Roadwarrior]

Thank you very much, got everything hooked up and managed to kinda get it started and running. But then I quickly found out that the carbs all need to be rebuilt as they are all leaking like sieves. But at least it runs and seems to idle decent. Now to pull the carbs back off and see if I can manage to rebuilt them.

[DiverRay]

Do NOT dip the carb bodies!! you should be able to clean them with spray carb cleaner.

[WMarshy]

You may have noticed that petcocks have ON, RES, & PRI. The petcocks have a vacuum diaphram in them that opens when engine vacuum draws on them allowing fuel to the carbs (in the ON position). In the PRI position the diaphram is bypassed and allow fuel to the carb bowls regardless of engine vac.

If the petcock diaphrams are bad fuel may leak to the carb bowls when left in the ON position and if your carbs are dirty and/or the float valves in the bowl dont seal good gas can make its way into the crank case as the carb bodies just dump fuel into the intake. This causes many headaches to newer folks and can damage your engine if you run it with diluted oil. Even if you clean your carbs it can still happen. Its highly suggested you add inline fuel filters prior to the carbs to catch any garbage. You can modify your petcock to have an off position without too much trouble too. As long as the rubber o-ring in the petcock is good it will work great.

http://www.xs11.com/forum/showthread...ht=petcock+mod

Add the custom OFF position and ditch the vac lines to the diaphrams and cap the carb boots. Or keep them, your choice. Welcome to the site.

[cajun31]

general guide video

here is a video on youtube http://www.youtube.com/watch?v=95nlrP-yn2I.

use this as a general guide as our carbs are a bit different. Few tips as you proceed. As diver said don't dip the carb bodies as there are seals that can be damaged by most cleaners. I have seen some say that you can use simply green diluted to accomplish this task with no damage but unless the carbs are really bad this is not a necessary step. Keep all your carb parts separated by carb so that the same parts that come out go back in the same bodies. There is no reason to totally disassemble the carbs from the rack. Just remove the parts as described in the video and give them a good cleaning with a carb spray cleaner. Make sure all ports are clear by spraying cleaner through all orifices. Compressed air help as well. You can spray some cleaner in a small container and soak all the jets as you remove them, again being sure to keep them separated by carb body. About the only other thing you need to do is check the float heights and float seal assemblies to be sure they are not the source of your leaking/flooding condition. Check out the carb 101 thread in the maintenance section for doing this. If you don't have to remove the floats your that much better off. The float posts are easily broken. If you feel the need to remove the float pins do so with extreme caution and follow the tips very carefully. They can be removed safely, just don't let frustration cause you to be overbearing with them. Many a carb has been ruined in this manner.

Good luck.

[mack]

Just a couple

things to be aware of when you clean your carbs. First, there is no such thing as being too clean. Second, you live in canada so ethanol is in the gas. When you order parts, get the non viton tipped needles and seats. Third, don't accept K&L jets. They stink!!! Fourth, if the fuel needles and seats are working properly, you will have no leaks but the petcock diaphrams do fail(more ethanol) and can cause other delivery issues. Take the time and rebuild them while your knee deep now!
There are several XS people in your area who can help with all sorts of advice, use them. And last, check the tips categories on what to do for an old XS. Change the fluids and check the brakes etc. are a good start but there is so much more if your going to be safe. It's tough enough to be safe with the yahoo's out there, you don't need the added hassle of mechanical issues!!!