No vaccume?

[regal21guy]

Hey guys i have a 92 bandit 400 and ive been having some problems with it. I think i narrowed it down to a vaccume problem. I dont have any vaccume at the line that goes to the petcock..... any suggestions on what i should do?

[tabby]

That line goes to one of the rubber manifolds. Check to make sure the line is attached properly, isn't split, or clogged. Also, you might want to check the clamps on the manifolds. If they are too loose, that could cause a loss of vacuum.

[Levi]

I'm having the same problem. It ran great then it started to run rough one day. Now it wont start. Did you solve your problem? If so CAn you post it so I can see man? Thanks .

[Aussie89Bandit]

Hey, I had the same issue. It ran great for about 3 months, then got harder to start over 2 months, then it wont start at all. The odd occasion that it does start, it's once only and wont start again.

its drivin me nuts. i've rebuilt the carbs, cleaned them out a number of times, checked for air leaks, set the floats at a number of levels, replaced the plugs, replaced the ht leads, done all the standard checks, even adjusted the valves twice.

I'm ready for a bandit bonfire the yard.

I'll take any ideas from anyone. I've exhausted this board for all its post on hard to start or rough idle, or not starting for ideas. none worked. Please help, I need to  again. I'm loosing my mind.

[Paul-B4]

I have had this problem.. make sure there a no kinks or bends in the pipe.

My vacuum pipe is about 2 foot long I have routed to make sure it will never bend.
 when I was having a repair at the shop the mechanic shorten the pipe thinking he was helping and the bike ran like shit, so don't be scared of getting a long pipe and going round in circles.

The vacuum only works when you crank the starter If you have been repairing the carbs make sure to suck on the vacuum inlet on the tank with the main fuel line attached this will draw the fuel down and help when starting as the bike wont need to turn over as much.


 

[Aussie89Bandit]

Paul-B4,

  for your help. I've had a small tank off one of my pocket bikes as a test/remote tank, and it has no change. I do get no. 2 cylinder firing (can only tell by putting my hand on the headers).

I will try your idea though. See if it changes.

[Aussie89Bandit]

I'll think I'll post a new thread as to not Hijack this one.

[Levi]

I had the same problem at one time with the no vacume at the petcock. My soulution for that was to buy new vacume line and get some good high temp clear or black sclicone. So it dosent show up like orange but that will work too. Anyway clean the intake boot where the hose connects. I took my intake boot  off and found my nipple in the boot to be almost plugged. Clean it out make sure the nipple is sound. Meaning no cracks if you gently push on one side if the nipple. Check around the base. Once everything is clean and dry , put a nice thick uniform bead of silicone around the base of the nipple. Then push on your vacume hose all the way on so it smoshes into the silicone. DONT touch it and try to make it look nice. Leave it to dry. Your not going to see it anyway. This should give you a good seal on the boot. The silicone is just to ensure the hose and nilpple never leak. Re-install the boot. My was pulling perfect vacume after that. However it still wont run. LOL  its startS but misses. Back in the carbs i GO.