vaciuum problem ?????

just started my kz750-e3, and........
pretty much the same problem as last week!!!
well at least my carbs are cleaner now
as i just cleaned them again !!

I guess it started a little easier but still pretty much the same prob.
it runs with a rag jammed in the top of the air filter top ????
pull it out slightly while the engine is running and the bike begins to die,
stuff it back in and it comes back to life.


after 5 mins idle around 2000rpm (won't rev without cutting out)
cylinder 1 - hot
cylinder 2 - warm
cylinder 3 - RED HOT !!
cylinder 4 - hot

tried the wd40 intake tip and no change in rpm's
It feels like a vacuum problem (right or wrong ?)
but can't think of anything else to try.
hope my findings help someone to HELP ME !!!!!!

thanks

Sounds like your running super lean. If the bike has a richener circuit, open it full and observe any change.
Check the condition of your plugs, and compare them to a good plug chart. Here's a real good one: www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html This will tell you alot about whats going on in each cylinder.

I am saying this with the assumption that all your valve clearances are correct, and compression is good.

Good Luck.

Dont forget to check for posible vacuum leaks everywhere in the carburetion path...

I saw your other post on this subject, a while back, and figured one of the other guys would ask this. If I understand you correctly, you are using a stock airbox w/filter. Here's where I'm a little fuzzy on whats going on. Are you stuffing the rag on top of the airbox because you don't have an air box lid, or are you stuffing the rag in the box and then closing it up w/the lid? I could see, if you were using the rag as a lid, you could be just getting too much air going through the airbox, especially since the box lid is required to keep a good seal on the filter. It would seem using a rag for an airbox lid would not be much more sealed than an open airbox.

The pilot circuit is plugged up or the pilot jets are obstructed. Are these CV34 carburetors? I suggest you FIRST give a bit of back ground. Have you eliminated other tuning issues by adjusting your valves? How is compression? It may be that you have an ignition issue as well as a carburetor issue. Sounds like cylinder #2 isn't firing at all. You might want to spray some water via a pump bottle (orange cleaner also works well or Windex) on the pipes. If the cylinder is firing, the water will vaporize. If the cylinder is non-firing, the water will spit on the pipe and roll off. Do this and get back to me. ID the carbs... It is a bit tough to clean the pilot circuit on the CV34s... harder than on BS34s.

the lid is on the airbox, I'm just stuffing the rag into the hole in the lid of the airbox acting like a choke i guess. all the components are there for the airbox it just ain't workin' !!

I haven't checked the valves because this really all started straight after i took the air filter out and replaced it.
before that the bike ran ok (not perfect, but alot better than it is right now)

UPDATE !!!!!

just went out to try again and put the petcock to prime !!
and it started alot better and stayed running.
the idle was a little irratic though.
i did the squirt test on the exhausts like you suggested george. 1,3,4 it evapourated to nothing and on 2 it just trickled down

also it is now backfiring alot

still progess (kind of !!!!)

Can't help you out if you won't answer the questions I put to you. Sorry.

How do i i.d the carbs george ?

they have Keihin on them so i presume they are cv34's

Would have done as well to figure out why the cylinder wasn't firing... I think you have Keihin CV34 carbs. The advice Limey gave for removing the pilot jets is pretty good... the right slotted screwdriver is critical. With the right screwdriver, I press hard and remove virtually 100 percent of the pilot jets. They have little thread on them so they are not stuck all that bad. If I do strip one, I use an EZ out type tool except I use the tool that is square and drill the proper sized hole. Don't drill too deep or you will just pop the head off.