XJ700 Maxim X air out of vacuum ports

i am so confused and this problem is driving me nuts.. I have an 85 xj700 maxim x that i have been working on to get it right. when i bought it i got it started after sitting for 12 years by former PO. It ran but not very well. I finally cleaned the carbs (3 times now) bench snyched and i can not get this thing to fire. I have good spark in all four plugs and fuel seems to flow but nothing happens. I even sprayed a couple shots down the vacuum ports at the top f the manifold to see if she would fire...nothing.... Then i noticed while cranking the motor that air was coming OUT of the vacuum ports on each cylinders. Shouldnt it DRAW??? I need to mention that i adjusted the valves replacing 11 guysor the 20 and although i removed and reinstalled the cams i felt good about that process as I was pretty anal about the whole process to a fault. So now im stuck and need to know if anyone else has run nto this situation....Thanks

 

I have a vaccum issue right now and I can see air coming through the hose when I have the fule valve set to on. When I put it on the prime it starts and runs fine. Maybe try that if you haven't already? And as far as I know I belive the vaccum line is blowing into the petcock? If I am correct. So air should be coming from them. My xj650 has one line for vaccum and the rest are plugged. I am sure you have done this, but when I go to restart it for the first time I make sure the mixture screws are out 2.5 turns, check though I have a xj650. I hope this helps.

 

1st how can you see air blowing thru the hose . To check pull the vac line off the petcock start it in prime see if you have vac if so your petcock is bad. if its blowing towards the petcock you either have a valve to tight a burnt valve what ever it is is pretty major it will also run pretty bad with a dead cyl

 

your cam timing is off

 

Boy did I dodge a bullet... Found the problem by accident while checking over everything. While i had good spark it appears I didnt have ENOUGH spark. While checking my plug wires and coil wires i found a wire pinched to a mounting bolt. I got it free and she lit right up and idled great. Turned it off and wiggled he wire and nothing...wiggled again and fired right up. Pulled the coils and repaired it..Still not sure why i was getting air pumping OUT but ill leave sleeping dogs lie...Thanks all for your imput

 

Air pumps OUT when the intake valve is closed because of YICS.

Don't sweat it, the system works fine as long as the three ports are plugged, your vac line to the petcock is solid and your valves are in spec.

 

The X doesn't have a YICS passage, Fitz.

 

I would bet your intake valves are sticking and not closing properly.

I always recommend pulling a head and checking the valves/rings as a first step on an engine that has sat for an extended period of time under who knows what condition.
IF you have stuck rings or sticking valves, it takes only a couple seconds of reving to damage expensive parts.
Pulling the head will only cost you time and a couple gaskets....piece of mind knowing that everything on the top end is function helps a lot.

Pull the head. I'll bet you have sticking valves.
Clean them up, lap the seats, make sure the rings are all free and put it back together. ....it's also a good way to learn what's inside ;-)