Vacuum Leak on XJ 550 Maxim

Hey guys so as the title says, i've got a vacuum leak on my bike, and i don't know from where, but i am suspecting its from one of the hoses thats not plug into where it should be, or my old Carburetor Boots! i need some help finding and solving the problem, i have already ordered some new Boots and they should be on there way, but i need to figure out where this hose thats not in the Engine goes in the mean time, So let the investigation begin!.

 

there is only i vacuum hose it is the smaller hose on the petcock and it goes to one of the brass ports on the intake manifold boots if you look at them each one has a tube and cap the vacuum hose goes on the one with out the cap. if you still have the old hose replace it with 4mm vacuum hose. you must use vacuum hose.
the manafold boots can may have a leak as well. clean off the boots with carb cleaner then coat them with black rtv fuel resistant type. you can do the same to the airbox boots. second option is to replace them.
you may also want to replace the caps and clamps.
the next thing to do is use carb claener or wd40 or unlite propane torch to check the throttle shaft seals each will cause a change in the rpm when used

 

Okay I'm gona take a look at them, when i get a chance.

 

see the brass ports thats where the hose goes and cap the rest.

it is the smaller id hose . fuel line is 6mm

 

If you replace carb boots, I recommend avoiding the cheapo ebay ones. Several on this forum report they have had problems with them literally disintegrating on the inside.

XJ4ever (top right link on this site) is a good source.

I just coated mine with RTV and its been good for several years.

As mentioned, propane, WD40 or starter fluid can be spot sprayed in areas of suspected leaks, and listen for engine idle change.

 

Well i already bought them so guess We're just gona have to wait, see, & find out! I paid 98.99 i dont think thats cheap! and i was looking at the carburetor/starter fluid solution, and figured maybe if i can get it to idle then i could check with some starter fluid, but the engine just keeps stalling out then dying on me, so i said forget it I'm just going to buy the New Boots and see if that fixes it.

 

View attachment 28139

Okay, and I'm trying to attach a picture but it will not let me, I'm using my Phone!

 

Okay, and here is the Hose thats not in the Engine.

 

Here are more pictures!

 

That tube looks to me like the battery overfill drain tube/vent. It attaches to the side of the battery, and runs down to underneath the bike.

As mentioned above, my stock '83 XJ550 Maxim only has one vacuum tube. From one of the carbs to the petcock.

 

Okay, so it must be the Boots or something else, well thats good, that narrows it down to just a Carb/Boot Leak/ but i'll check some other area's just to make sure!

 

Have you FULLY rebuilt your carbs? This could also be source of problem ...butterfly seals after 30 years are many times leaking from rubber drying up . To obtain new seals go to xj4ever ( you WILL NOT find them on eBay) ...To replace you have to pull carbs off the rack and pull butterly plate and pull shaft ...This is the time to fully soak the carb bodies in carb cleaner ( READ CHURCH OF CLEAN) . Be very careful removing boots bolts can snap, when putting back in put anti-seize on the threads of the bolts before installing .

 

+1 ^^ 0n the shaft seals check them with spray

battery drain hose it hooks to battery if you have a wet cell

 

why do you think you have a vacuum leak?

start with the simple things like the vacuum hose 4 mm
high idle did you back off of the idle knob at the rear of carbs?
throttle linkage lubed and free moving?
properly adjusted with a little slack?
seated properly in the cup?
you do have the little short cable on there too?

 

Alright fellas so i found the source of the problem! Vacuum hose/line was off of the petcock, must've happend when i was messing around and fixing with the Electricals, just took him for a spin, and he ran fine, still gona replace the boots when they come in so i won't have too many problems in the future with the vacuum system!

 

now on to the next one, i need to bleed my front fork but the bleeder valve is rusted/seized how do i go about getting it off?

 

And also does anyone know where or how to dispose of our motorcycle's batteries?

 

Most walmarts have recycling on batteries , you should have a core charge if you bought a new battery , even if you ordered on line you should be able to find a place that will take your battery on line local to your area. Thanks for thinking about the environment

 

I trade mine in when I buy a new one to avoid core charges.

My bleeder valve was not really rusted, but hadn't be opened in 20+ years (mine is a one owner bike). I sprayed it with penetrating oil a couple days in a row before using a high quality (8mm?) box wrench to open.

 

Are you refereeing to the brake caliper bleeder valve ? If so soak in penetrating oil ( PB blaster/ Kroil) and See if you can free it , if it snaps off you will need to drill and try an easy out.