1981 KZ550 D1 GPZ550 won't start

Hello All:
I was reading a thread earlier but have lost it now regarding KZ550's not starting. I have an 81 GPZ550, it was mechanically rebuilt about 3 years ago and has less than 400KM on the rebuilt. It was running fine earlier this summer but suddenly would not start. It has spark and fuel and a new battery. It cranks endlessly and won't fire. 

Please tell me if I'm wrong but I think the clutch must be in for the bike to start, and on this bike the clutch needed to be about 3/4 out it seems to me before it would fire. It was never a good starter. The coils are getting power (I suspected the igniter) and the sparks are sparking. Nothing was touched with timing. The gas is good. The only think I can think of is the clutch switch (assuming there is one) that prevents it from starting if the clutch is not in. A friend had a look at the wiring diagram and says there is no clutch switch but I think there is. I can't make sense of that diagram... I'm wondering if anyone else may have had a similar issue? I don't know what the check next. The plugs were not well gapped, did that tonight but no difference, they are black like it last ran rich. I'll get some new plugs.

Thanks for any suggestions. One other thing... this bike has sat a lot in the past few years and the tires leak and go flat. Has anyone tried that goop that you put in the tires to prevent leakage, rather than buying new ones? They've sat on the rims to much I think I'd better find some new ones. 

Ron

If it was a clutch switch it wouldn't crank on the starter button (I believe) - have you tried a squirt of easy start in the intakes ? at the end of the day if you have all of the below it should start 

1. Compression
2. Spark
3. Air
4. Good fuel (getting through the carbs)
5. Correct timing
6. Good battery voltage

Ref the tyres, it is likely corrosion on the rims stopping the tyre from sealing against the rim - the "goop" you speak of is a "get you home" solution not a "fix" for a problem !!

Got it, thanks. The coil wires were not going to the cylinders indicated in the wiring diagram. I corrected this I think, although I don't see 'green' wires as indicated. Also installed 2 new plugs (2 more coming tomorrow), primed those two cylinders, but still nothing, not firing at all. Tomorrow I'll get the other two plugs and some high octane starter fluid. There's been some damage being done around the strata we live in, screws under tires, my car hood scratched, etc. It's possible these wires being switched was part of that.

The clutch connection...maybe I'm just wrong on this, but it seemed to me (I've had this bike about 10 years) that the bike would not start unless the clutch lever was at a very special place about 3/4 of the way released, almost fully released. It just wouldn't fire until it hit this place. Could this be what the problem is? Or is the clutch/starter connection just a simple one where the starter won't spin unless the clutch is pulled in?

Ron

I have the same bike!

I experienced a similar problem, - not starting...
I parked it after an uneventfull ride one eveneing...
The following morning it would not start. It would crank (with clutch lever pulled in) but would not fire...

I found the problem after much head scratching and probing with my multimeter...
The ignition pickup wiring had fractured INSIDE the pick-coil... 
It is quite common for those wires to fracture right there....

I'm not saying you have the same issue, but check your ignition pick-up coils...



When I pulled lightly on the black wire entering the pick-up coil, it came out in my hand!
With nothing to loose, I decided to "dig" away the insulation material, and was VERY fortunate to expose a tiny piece of the
remaining copper wire...

I carefully soldered the wire back onto that little piece of exposed copper... 



I covered the joint with Epoxy adhesive (JB Weld or similar) to provide some "strain relief" 
The engine fired right up after that and has run perfectly since then.

H. 

Mines really hard to start after its been sitting. Best not to give it any throttle. If the clutch switch was bad it wouldn't turn over. Best to pull choke, try it then wait then try it then have a smoke try again.. Mine always starts hard after sitting all winter. If you have spark and fuel should start.

When mine won't start after sitting for a while, I pull the carbs and clean the pilots. That usually solves it. I try to start them all at least once a month. 

Hello All:Thanks for the replies and images! HowardHB I had to check my bike was still here after I saw yours. I am going to open up the timing and have a look, pretty sure its not that now however, but it should be checked.I got the bike started finally, installed new NGK Iridium DR8EIX plugs (you don't gap these it seems), properly (?) routed the coil wires (left side of left coil to C2, right side of left coil to C3, left side of right coil to C1, right side of right coil to C4) which had been wrong, then did what someone suggested many hours ago - check the gas. I'm embarrassed to say it smelled like watered down turpentine. I've been adding small amounts of good gas but that obviously didn't help. I drained the tank then the carburetor bowls, then tried again. It started... but not without a significant amount of high octane 'quick start' spray. It runs roughly, but only if the choke is fully on, and the rpm is kept 3-4k or higher. Below that it fumbles and stalls, and even when warmed up and running fairly constantly at 4K if you even touch the choke it stalls. The gas is flowing freely from the tank through the filter. The gas line runs from the tank through the inline filter then down to a metal inlet pipe between cylinder 2 and 3, but I notice there is another two plastic input pipes between cylinders 1 and 2 and 3 and 4. It looks like there should be a gas line connected to these as well, but there never has been that I know of, and they are sitting there not connected to anything. Does anyone know about this?It still feels to me like maybe the coil wiring is still not right, it runs fairly smoothly at higher RPM but it's hard to tell at that speed, but below 3K its struggling to stay alive, and any movement off full choke and it dies. I'm confused by the high choke sensitivity... what is that saying? The bike was running normally in the spring then just wouldn't start one day, so I'm thinking its probably not a timing issue, also I don't know how the timing works and am afraid to touch it. This bike has the 4 small pod air cleaners which look cute but don't fit well (although they are convenient when working on it) I'm going to try to put the original air cleaner back on but am missing one mounting bracket. Thanks for your suggestions. It did start twice today (when warm) without the high octane primer spray, so there is progress.Ron  The attachment image is not from my bike, but an 82, but looks the same.

What you describe are classic symptoms of clogged pilot circuits. The only solution is to completely dismantle each carburetor and soak all of the metal parts in strong carburetor cleaner, run a piece of guitar e string  through anll of the tiny passageways, blow compressed air through all of the passageways to be 100% sure they are all clear,  and replace all of the rubber parts. The slide diaphragms may be reused if they are not torn or full of holes and cracks.

The fittings circled in pink are bowl vents. Each one should have a rubber hose that goes down in front of the swingarm pivot.

Got it TexasKZ, thanks. Carbs also scare me, but it sounds like I'll have to learn.
Ron

Lots of info here on louds site RIP  .Still helping people after he's gone.

  index Lou D's Motorcycle Stuff

Everything you need to know about your 550. Scroll down there's a whole link on your carbs.

Thanks for the links, good information. This sounds dumb but I'll ask. As I just had pod air cleaners the carbs are easy to get at. I've loosed the screws (about 1") that tighten the ring around the inside of the carbs against the cylinder head, and released the throttle cable, but although the carbs seem pretty loose and wiggle up down about an inch there is something still holding them on. I'm afraid to pull any harder. Is there something else I'm missing here that needs to be released?

I see my bike has only one throttle cable, the puller cable on the left side, I wasn't aware there is supposed to be another cable to the right side which I assume is a pusher cable. Just after the engine rebuild this bike had several occasions when the RPM just went out of control, up to 5-6K stopped at red lights etc., I had to put it into higher gear and stall it out to get the rev's down. Embarrassing and concerning. I couldn't understand what was happening, nor could the cars beside me, the engine builder said everything was fine. This was no doubt the problem. So I need a new push/pull cable I think. Any suggestions on where to get that? As the carbs were rebuilt 3 years ago and mileage is very low, I'm hoping I can get by just cleaning the carbs and not installing new carb kits.

Ron

I just got the carbs off, using more direct persuasion.