whats your thoughts on intake manifolds

[OpFlash]

hey there just wondering about the intake manifolds on the xj1100 yes mine are a bit cracked. ive heard that these are a big problem with our bikes. thinking about picking up a new set i know big bucks! just wondering are you guys still running with the old ones repairing them whats up? and how much of a performance difference will leaky ones make? thanks

[Jerry]

There have been reports of manifold boots leaking, but the common issue is one of cosmetics. If you suspect your boots are leaking, try this. Take can of WD 40. Start your bike, and spray some WD right at the base where the boots meet the head. If your RPMs pick up you have a leak. (Make sure the clamps on the carbs are tight!) The boots have an inner liner that is quite durable, so surface cracks are generally not a performance problem.

If your boots are leaking you bike will run lousy (lean) and no amount of carb tweaking will help. Lean condition leads to early engine failures.

Many have used black RTV sealant to coat/patch the boots, but if you really want it to look good and perform like new, new boots are in order.

[OpFlash]

well heres my situation. my xj has 1139 miles on her but shes been sitting shell turn over and run nice with choke on and eventually idle with choke off but when throttle is applied shell die. im in the process of gathering all the essentials for a real nice tune up on her ie oil filter oil plugs air filter brake pads brake fluid fork oil master cylinder kit etc. the boots that are on are pretty hard but as you suggested appear to have some surface cracks on them. not sure if they go all the way through but. ive heard that the old boots can be a problem. and right now a new set is within my budget as far as my set repairs to get her up and roadworthy running. I also am in love with this bike and dont plan on getting rid of her so im also thinking about longevity. However im also not into throwing money away when its not needed, but my thoughts are that parts may not always be available. whats your thoughts

[RUSH]

my first thought is to change the oil and filter. then check the air filter to make sure its clean. Now make sure that the vaccume advance hose is connected and has no holes. remove the side cover and start the bike and see if it is functioning and at the same time spray your carb boots with wd40. if the idle changes with the wd40 spray than your boots have leaks. Either coat them or replace them. I would replace them because your going to be pulling the carbs off to clean them. If you find the vaccume advance works but the bike still dies, check the pickup coil wires to see it theyre worn. They shouldnt be with the low miles, but you never know. If they look good you could go the extra step and check the ohms reading on the pickup coils using a multi meter and some needles to probe the wires. Oh yeah, Do you have the book for your bike yet? If not, get it. If the ignition checks out so far then its time to yank the carbs. Search the site for more info on this topic and read the manual.

[skids]

I don't know much about the access to the carbs on an XJ, but if you can get to the slides with the airbox out of the way, reach in and make sure that they slide up and down freely.

Originally posted by OpFlash
well heres my situation. my xj has 1139 miles on her but shes been sitting shell turn over and run nice with choke on and eventually idle with choke off but when throttle is applied shell die.

[81xsproject]

when checking for intake leaks WD-40 isn't all that volatile or flamable. I have found that starting fluid works a whole lot better, requires a whole lot less, and above all doesn't leave you with a smoking, stinking mess on the engine. Just a suggestion as I have sprayed WD directly into running carbs before with almost no RPM increase. If anything it bogged it down.
JC

[MAXIMAN]

I've changed 4 sets of boots on 4 different old Yammy bikes in the past year. All the intake boots were perfectly fine with the sole exception of one. More often than not...the cracks are superficial and purely cosmetic. But like they said .. WD40 will show if it's really leaking.

When I changed them on Zilla the bike ran no different afterward....but boy it sure did look nicer.

[Ken Talbot]

OpFlash - the symptoms you describe, where your bike will start and idle okay then die when you open the throttle, point to dirty carbs. That should be your first task, along with fresh oil and filter.

[lsippell]

There is no vacuum advance on an XJ. Just a boost sensor that picks up vacuum from the # 2 carb to send a signal to the computer, which electronically advances or retards the timing.

Louis

[OpFlash]

youre right that my problems are more than likely carb related i guess that my real question is would you guys out there replace your manifolds if they were hard and slightly cracked with new ones due to their age and for general maintenence's sake regardless if they appeared to be leaking or not. im looking to make this bike as perfect as it can be because i truly am keeping this bike forever