Losing 1 cylinder at idle...

Apparently, I'm still inept at carb adjustment. Fixed my plug-fouling issue, but I'm still fighting a very rough idle. Won't run smoothly below about 1200 rpms.

My mechanical synch didn't help much. Tried adjusting the pilot air screws per the manual, started out 1.5 turns and searched for highest idle from there. 2, 3, & 4 adjustments all made a difference. Cylinder 1 made no impact at all, all the way in or way out, no change.

What does that mean? Clogged pilot jet? That might explain some of the rough idle problems. Haven't had time to pull it apart again yet. I've run a full tank of fuel through. So far so good, runs great off idle, just idles rough.

Once I figure out the non-functional pilot screw, I may pony up and buy some vacuum gauges so I can synch them.

LukeMacPU wrote: Apparently, I'm still inept at carb adjustment. Fixed my plug-fouling issue, but I'm still fighting a very rough idle. Won't run smoothly below about 1200 rpms.

My mechanical synch didn't help much. Tried adjusting the pilot air screws per the manual, started out 1.5 turns and searched for highest idle from there. 2, 3, & 4 adjustments all made a difference. Cylinder 1 made no impact at all, all the way in or way out, no change.

What does that mean? Clogged pilot jet? That might explain some of the rough idle problems. Haven't had time to pull it apart again yet. I've run a full tank of fuel through. So far so good, runs great off idle, just idles rough.

Once I figure out the non-functional pilot screw, I may pony up and buy some vacuum gauges so I can synch them.

There's several things that affect the pilot circuit function, did you replace the o-rings on the pilot plugs that cover the pilot jet itself on the upper half of the carb? Everything needs to be good in there and perfectly clean. I believe the pilot jet merely adjusts the amount of air that passes through the pilot circuit. If the pilot jet itself, which lives right next to the main jet and a bit forward of it is restricted or clogged, you won't have any fuel passing through the circuit. Float level also affects this since the pickup point on the main jet port that angles up and into the pilot circuit likewise has to be in the fuel. I'd make double sure all your float levels are as close as possible, check those pilot jets and plugs. The o-rings on those pilot jet openings get petrified after years of fuel exposure and heat. There's several small passages in the carb, like the enrichment circuit, so you will have to make sure every one is clear and clean. If you are getting no change with #1 pilot, there's little or no fuel/air passing through the circuit.

You don't need expensive synch gauges.

The pilot circuit fuel mixture should exit through a small orifice into the carb throat.
Sometimes the orifice gets clogged.

Good Fortune!

DiamondSkyBlue1000 wrote: You don't need expensive synch gauges.

Nice home-made set up. ATF as the fluid?

Cleaned out my pilot circuits again. The pilot jet on cylinder 1 was pretty well clogged. Re-installed and my idle is better, but still not smooth.

I'm thinking vacuum synch next?

LukeMacPU wrote: Cleaned out my pilot circuits again. The pilot jet on cylinder 1 was pretty well clogged. Re-installed and my idle is better, but still not smooth.

I'm thinking vacuum synch next?

If not already done, would first assure that valve clearances are within specs, and also install brand new NGKB8ES spark plugs, assure fuel level is correct by performing the clear tube test, and then try for best idle by using the pilot adjustment screws.

After the above, proceed with vacuum sync.

Recall that vacuum sync is the final engine tuning procedure.

Good Fortune!

Have done all of the above, by suggestion of the helpful folks on here.

The Good:

Rode the bike this morning, for the first time since re-cleaning/adjusting my pilot jets. Much less popping on deceleration and generally seemed to be running a little smoother in the 0-1/4 throttle range.

The Bad:

It was 36 F this morning when I took off.

I'm still having to adjust my idle up when it's cold to keep it running. Once warm, that same idle position equates to 2200+ rpms. I've just been adjusting it back down at stop-lights/signs as it warms up, but it seems this shouldn't be happening.

Any thoughts about why this might be occurring? Is this normal at all?

You're still running lean on the pilot circuit, sounds like. What pilot jet numbers are installed? That slow-to-drop idle and sluggish type rise at idle sounds like when the pilot needle is opened too many turns; but if you have to open it 3.5+ turns, that also suggests some intrinsic lean problem. Again, what's those jet numbers? With stock everything, they were 37.5 on my 1100 and that ran perfectly smooth, like a sewing machine at idle.

Breaker19 wrote: You're still running lean on the pilot circuit, sounds like. What pilot jet numbers are installed? That slow-to-drop idle and sluggish type rise at idle sounds like when the pilot needle is opened too many turns; but if you have to open it 3.5+ turns, that also suggests some intrinsic lean problem. Again, what's those jet numbers? With stock everything, they were 37.5 on my 1100 and that ran perfectly smooth, like a sewing machine at idle.

Pretty sure, the pilot jets were marked 17.5. That's sounds small compared to your 37.5's.

My pilot air screws are set roughly out 1 turn. Started at 1.5 per the manual, ended up with best idle around 1 out for most all the carbs.

It'll drop to idle fine, and won't creep up except for when the bike is warming up. Once warm, it stays where I set it. That same idle setting won't keep it running when the bike is cold so I have to adjust it up until the engine is warm.

LukeMacPU wrote: ... re-cleaning/adjusting my pilot jets. Much less popping on deceleration and generally seemed to be running a little smoother in the 0-1/4 throttle range... having to adjust my idle up when it's cold to keep it running. Once warm, that same idle position equates to 2200+ rpms. I've just been adjusting it back down at stop-lights/signs as it warms up, but it seems this shouldn't be happening.
Any thoughts about why this might be occurring? Is this normal at all?

Any thoughts about why this might be occurring? --- would suspect imperfectly cleaned pilot circuits.

Is this normal at all? -- Nope, shouldn't have to adjust it back down at stop-lights/signs as it warms up.

re-cleaning/adjusting my pilot jets -- A step in the right direction. Would now proceed with cleaning the rest of the pilot circuits.

Z1 doesn't suffer from inherent leanness as do some of the later models.

Good Fortune!