TOPIC:

I started up my 1976 KZ900 after it has sat for a couple of weeks and noticed that it didn't sound right, like it wasn't running on all cylinders. Found that the #2 pipe was cold. I also found out that whenever I tried to put the bike in gear, it would lurch forward and cutout. I took the clutches out and they were hard to separate, but I got them separated and put them in some oil to let them soak overnight. In a hurry to get things done before dark, I changed the #2 spark plug and started the bike to see if the #2 cylinder was now firing, which it wasn't. I swapped the #2 and #3 plug wires and #2 still wasn't firing. I took the carbs off and cleaned the #2 carb. Put the carbs back on and put the clutches back in, now the bike will not start. I checked and do have power to the coils. By starting the bike without the clutches in cause the bike not to start now ? I am going check to make sure I have fuel getting to the carbs through fuel filter next chance I get. Just want to make sure I didn't screw something up by starting the bike without the clutches in it, which I don't think it should have.

I checked on this again today and still unable to get it to start. It does turn over, but won't start. I am seeing about 12 volts to the battery and I am getting fuel to the carbs. I am also seeing battery voltage going to the electronic ignition. The bike was running until I took the carbs off to clean the #2 carb and taking the clutches out. Anyone have any ideas ?

Will the engine start and run momentarily by using starting fluid spray into the air intakes?

Good Fortune!

You can use WD40 as a starting aid. Squirt a SMALL amount in the plug hole and then try to start. If it fires, you have a fuel flow problem. These bikes need a very good battery with a full charge to start. Try not to use the choke.

when you removed the clutches didn't you lose the engine oil?
or is there enough left in the sump to run it momentarily?
leon

petcock failure - filter clog, bad diaphragm on the vacuum style or simple passage clog
check fuel/air hoses for kinks
points not juicing enough for a start, clean and set gap

the #2 is connected to the petcock (if it's vacuum style), could be an overflow/flood/rich type of problem. If the #2 carb has a fuel accelerator on the bottom it could be clogged there.

I've had a similar issue and pulled the tank off and ran a gas bottle through a fuel filter straight into the carb to rule out the petcock or the tank (make sure the vacuum hole on the gas cap is open)

Almost 99%... it's the points (if you have them).

Most of these thoughts are random and may not pertain to your 900, but I'm putting them out there.

I stopped on my way home from work yesterday and picked up some starter fluid and new plugs. I got home and tried starting the bike,, with no luck. Took the plugs out and they were all 4 wet and fouled. Sprayed a little WD40 into each plug hole and installed the new plugs. Bike fired right up and ran good. I put the original plugs back in to see if it was the plugs or WD40 and the bike wouldn't start, so the 4 new plugs went back in.. Thanks for the suggestions. I didn't think about the plugs since the bike was running a couple of days earlier.

if they were wet and fowled it must be flooding. you may need to rebuild the carbs. i had the same problem with mine. mine would run good for a day or so and fowl the plugs. after about 6 sets of plugs i finally gave in and had them rebuilt. ive had no more wet and fowled plugs ever since.

Ahhhhh grasshopper......are the plugs fuel fouled or oil fouled?

I took the bike for about a 5 or 6 mile ride. I checked the plugs when I got back and the #1 plug looked good. It is a greyish/tan color. The other plugs are dry and sooty. Any idea's on what is causing this issue ?

Are you using the crap 10% ethanol fuel that our shit government has forced upon us? Sounds like the exact problem I just went thru a few months back.

In mine the fuel had separated, phase separation it's called, and all the ethanol/water was being pulled into the engine. The dry sooty plugs is what makes me think that's your problem. Is it a gray soot on the plugs?

Drain some of the gas out and look for water droplets in it. If so you need to dump that tank and get new gas in there and always use something like marine stabil. This ethanol blended crap will go bad in just a few weeks.

Here is my thread on it....after draining the tank, purging the carbs and getting fresh gas back into the system all is well.

www.kzrider.com/forum/3-carburetor/596045-very-strange-gas

BIGKEVIN wrote: I took the bike for about a 5 or 6 mile ride. I checked the plugs when I got back and the #1 plug looked good. It is a greyish/tan color. The other plugs are dry and sooty. Any idea's on what is causing this issue ?

Usually, dry and sooty plugs are evidence of incomplete combustion, for whatever reason.

The reasons for incomplete combustion include:
Insufficient compression (for whatever reason),
and/or
Weak ignition (for whatever reason),
and/or
Too rich fuel mixture (for whatever reason).

From square one ---
Would assure valve clearances are within specs.
Would observe spark quality on plugs.
Would perform clear tube tests.

Good Fortune!