Carb Sync instructions 79 kz1000

650ed wrote:

richrand wrote: Z1-Ent Tech line suggested I swap the 1/4 and 2/3 coils to see if the problem follows the coils/wires. Its a great idea that I'd do if the 2/3 wires were long enough -- which they aren't on my machine.

Since you already swapped the #1 and #4 leads and plugs and the problem did not change I don't really see what swapping coils could prove. Since the coil, leads, caps, and plugs for both #1 and #4 fire cylinder #4 fine but will not fire cylinder #1, the ignition system would appear to be working ok. Ed

that suggestion was for Brady 154.

In order to dampen the needle movement, you need a very tiny restrictor as close to the motor as possible.

Here are some notes about manometers:

home.comcast.net/~loudgpz/GPZweb/Manomet.../ManometerNotes.html

If your carbs are of the VM variety (the stock carbs are VM), taking the caps off to get to the synch adjusters is not going to affect anything. That part of the carb is not in the vacuum area.

If they are of the BS variety (BS carbs are CV type) that cap is the cover for the vacuum bell and shouldn't be taken off. The adjusters aren't under there anyway.

Fluctuating needles means you need a restrictor in the vacuum tube going to the synch device. Vacuum fluctuations are normal and the restrictors dampen that out so you can read the synch tool better.

Vacuum readings on the synch device are not quantitative, they are for comparison cylinder to cylinder. If one cylinder reading is extremely low and yet everything is good mechanically on that cylinder, its neighboring cylinder is probably the cause of it. When you adjust one cylinder, the other cylinder reacts in the opposite direction.

If you have to enrichen one cylinder like that then check your slide position by doing a bench synch. Could be that carb is way out and you can't get it to dynamically synch in.

richrand wrote:

650ed wrote:

richrand wrote: Z1-Ent Tech line suggested I swap the 1/4 and 2/3 coils to see if the problem follows the coils/wires. Its a great idea that I'd do if the 2/3 wires were long enough -- which they aren't on my machine.

Since you already swapped the #1 and #4 leads and plugs and the problem did not change I don't really see what swapping coils could prove. Since the coil, leads, caps, and plugs for both #1 and #4 fire cylinder #4 fine but will not fire cylinder #1, the ignition system would appear to be working ok. Ed

that suggestion was for Brady 154.

I've swapped the #1 and #4 leads also, so swapping the coils "shouldn't" make a difference. I might give that a try this weekend anyway. It seems like #1 is maybe running so rich that it can't burn off all the fuel, but I don't know what would cause that since the others are fine and the carbs are new. Pit Stop Performance suggested checking the choke plunger and making sure it isn't stuck on the #1 carb, which would make a lot of sense as to why it is running rich. On my Mikuni RS34s the choke knob pushes all the plungers closed--at least on the outside of the carbs. I don't know about inside the carbs though. I don't really want to start taking the carbs apart--but I'm getting close to doing that.

Have you check the fuel level in bowls, also inspected pilot jets?

Tomolu5 wrote: Have you check the fuel level in bowls, also inspected pilot jets?

Not yet. That is next on the list to do this weekend.

the issue for me was a stripped carb holder clamp on #1. it would seem like its tightening, but it wasn't. fixed and running (of course not without some other problems).

Two quick questions:
1) Is spraying carb cleaner around the carb boots (between the carb and engine) and listening for any increase in RPM a good test of vacuum leaks?
2) I'm building a manometer type tool to sync my carbs. Does anyone know roughly what vacuum pressure a 1983 GPz550 (or similar) would pull? I just need a very rough figure to help with sizing of the tubes.

Thanks!

To test for leaks warm up the engine first; then using the throttle stop knob on the carbs temporarily lower the idle as much as possible without killing the engine. While it is idling spray carb cleaner around the carb holders where they mate with the cylinder head and where they mate with the carbs. If the idle is affected or the engine stops running the carb holders are leaking. If this happens when you spray at the carb holder/cylinder head joint you should replace the carb holders. If it only happens at the carb holder/carb joint you may be able to tighten the carb clamps enough to stop the leak.

There are 2 reasons for idling the engine very low for the test: first, with the idle set low the slides are practically closed, so the engine will try harder to suck air from any leak; second with the idle set low any variation in the air/fuel mixture caused by sucking in carb cleaner will have a larger effect on the idle compared to if it was idling high. Ed

Awesome! Had a problem with my GPz not idling, sprayed carb cleaner and all four were leaking. Took them off, cleaned them up and replaced, carefully tightening them down. Idles much more smoothly now I was wondering if the carb cleaner spraying was an accurate leak test or if I was living in a fool's paradise.

The bike still doesn't idle very well though, which I suspect is down to carb balancing being WAY off.