After 7 years its alive!, mostly..

Well the 73 z1 started and worked like a beast, even on 3 cylinder. After about 10 kicks she started popping after dicking with the controls. Then after a few more kicks she started right up. It was running, but not on the 1st cylinder. I could tell because the pipe on the first cylinder was cold. Even after it warmed up, it wouldn't run without the choke being on, im thinking thats because its only running on 3 cylinders, but could be wrong. I'm also thinking it might be a carb issue because the carb on the 1st cylinder was pretty bad.. It had tons of buildup, whereas the rest wern't too bad. I thought I did a proper job on the carbs, spent a long while cleaning them. Any ideas what the problem could be?

Heres some pictures

Thats what the first sparkplug looked like after running it for about 5 minutes with full choke. The rest of the spark plugs looked the same as the second one

#1 cylinder ---

If not already done, would attach brand new NGKB8ES spark plug to plug wire, ground plug base to engine head, spin engine over and visually inspect spark quality at tip of plug.

If spark looks okay, install the brand new NGKB8ES spark plug and again test run engine.

If #1 cylinder still fails to combust, would perform compression test on #1 cylinder. AND assure both valve clearances are to specs in #1 cylinder. A too tight valve could easily cause the reported problem (even where cold compression test seems okay).

When satisfied that both spark and compression and valve clearances are okay in #1 cylinder, would then perform clear tube test to assure fuel level in float bowl isn't too high and causing a too rich condition in #1 carb.

Given good properly timed spark with decent compression and correct valve clearances, and prescribed fuel level, if combustion still fails in #1 cylinder, the problem is probably carb related. Most likely an issue with the pilot circuit (or maybe the enrichener circuit) in #1 carb.

Pilot circuit passages, both air passage and fuel passage and air-fuel passages, are sometimes very difficult to clean. And sometimes the pilot jet is so dirty or damaged that it should be replaced with a new pilot jet of the same size.

Would also assure intake air filter isn't over-oiled or otherwise blocked. Some pod models may partially obstruct the pilot air intake hole. Could remove the pod on #1 carb for test run.

Good Luck!

Pull the carbs and go through them again. The number one cylinder will catch all the garbage from the tank most times. When it leans on the sidestand it makes since that number one will usually be in worse condition. It took me a few times of pulling the carbs to get my issue worked out. On mine one and two carbs were in rough shape.

Everything Patton said...

I may just cut n' paste this to several other locations! :laugh: :laugh: :laugh:

patton had good info.
does the #1 plug have gas on it?
leon

No, It did not smell of gas at all

KLD wrote:

No, It did not smell of gas at all

Sounds like almost certain to be a carb problem Best of luck gettin it sorted.


Cheers

c3

I pulled the carbs off and the float level was too low, so I readjusted it.
Did a quick compression test and it was good. It has good spark. It doesn't have any type of filter on at the moment to restrict air flow. Valve clearances are up to spec. The jets are clean as a whistle. So.. that leaves the fuel passages.. i suppose

Even on just three cylinders, should perform surprisingly well, and run with (or out-perform) most Harleys, and full turnpike cruising speeds being easily sustainable.

[Click on image to enlarge view.]



Good Luck!

Thats going to be very helpful, Thanks a bunch! I'll keep you all posted

Have you tried swapping plug wires 1 & 4?

See if the problem follows to #4 then it's electrical and not carbies....

Just a thought before having to tear apart the carbs...

OMR

KLD wrote:

I pulled the carbs off and the float level was too low, so I readjusted it....

Would more likely suspect a too high fuel level causing the black sooty plug from an over rich mixture.

Am hoping the clear tube test was performed.

When performing the clear tube test to determine float bowl fuel level, pulling the carbs isn't necessary. Because the clear tube test may be performed with the carbs remaining installed on fully assembled bike, without carb removal or disassembly. Bike should be held level and stationary during the test.

The clear tube test tells the true actual existing fuel level, regardless of float buoyancy and other variables.

Imo, the carb-disassembled-upside-down-on-workbench method (measuring physical distances involved) is a ball park adjustment to be confirmed with the clear tube test.

The clear tube test may also be performed with the assembled carbs on the workbench. Where the carbs must remain level during the test.

Too high fuel level in otherwise perfect carbs, and perfect everything else, will cause over rich mixture evidenced by black sooty plugs.

Good Luck!