1979 kz750 Starting Problems?

Ok, I posted earlier that i was having issues with getting my electric start to work. Now for some reason the kick start will not work. The engine turns over but will not start. I have tried checking the plugs and all the external stuf that could cause a starting problem. I am ready to tear into the engine but I would like some advice on where to start the troubleshooting. I have purchased a service manual. Please advise with any help or if you need more info to diagnose.

Thanks

Are you pulling the clutch lever IN while trying to kick start it?
Pulling the lever in prevents the kick starter from turning the engine over = no start. :S

No I do not have the clutch lever pulled. I have tried using full, half and closed choke. Nothing seems to work. I am not sure if its a carb issue or starter clutch problem, or something totaly different.

I have a 79 750 twin, and it starts on the second kick cold, first kick warm (good thing since the battery is bad).

If you want yours to do the same, then you need to do the following.

Clean and adjust points.
Check and adjust ignition timing.
New plugs.
Check and adjust valve lash.
Check resistance of coil. plug wires, and plug caps, replace components that don't meet specs.

After doing the above, apply full choke, turn ignition on, ensure shut off switch on right bar is on, turn on petcock, give it a good healthy kick. If it doesn't start by the third kick, then do the following.

Remove carbs, disassemble and thoroughly clean carbs, assemble the carbs leaving the float bowls off, flip the carbs upside down and adjust the float by bending the float tang that rests on the needle valve until there is 1" between the gasket mating surface of the carb body, and the bottom of the float (top, since the carbs are upside down).

Assemble the carbs and bench sync them by adjusting the throttle blades all the way closed, open it enough to stick a thin wire between the throttle blade and the bottom of the carb throat, hold the carb vertical and adjust each throttle blade until the wire falls out.
Install them, checking that the air filter is clean, if not then replace it.

Screw the little brass screw on the side of each carb all the way in, back it out 1 1/2 turns.

Start the bike and use the choke to keep the idle from shooting to high, after the bike is warm adjust the idle to ~1000 rpm by using the idle adjustment screw on the left side.

Now the bike should start with two kicks cold, one kick warm.

I highly recommend converting to electronic ignition using the components from a KZ440 or a 82-83 KZ750 twin.


Before anyone says the proper way to adjust the carb float level is to use a plastic hose and set the fuel at the specified distance from the mating flange of the carb, I have used the one inch method on three sets of 76-79 750 twin carbs, then checked it using a modified float bowl plug with plastic hose, and every time the fuel level was right in the middle of the specified range.
That's good enough for me.

Steel
I was reading another thread and the guy was having a similar problem with his electric starter. He replaced his starter with one that had more power, i believe the original was 0.6Kw and the new on he used was 0.8Kw. Do you think this would help get my eletric start working smothly??

I don't know if any other starter will work on a 750 twin, as I have never tried it, or read of anyone else that did.

The normal causes of starter malfunction, from most common to least common.

(1) Malfunctioning starter button (numerous reports, seen a couple)
(2) Worn out starter clutch (replace pins, springs, rollers) (numerous reports, seen a few myself)
(3) Bad starter motor (read few reports, seen one)
(4) Sheared starter clutch to rotor bolts (One report, seen one)
(5) Broken starter chain/sprocket (Read 0 reports, seen one)
(6) Rotor spinning on crank (Read 0 reports, seen one)


Keep in mind that a 750 twin is never going to spin over as smoothly as a four, it's just the nature of the beast

On my 79 KZ750 twin with electronic ignition (82 KZ750 twin electronic ignition), when it's warm all I have to do is brush the starter button and it fires instantly.

Quote:
"I highly recommend converting to electronic ignition using the components from a KZ440 or a 82-83 KZ750 twin."

Please advise on where i can find parts to convert to electronic ignition like you suggested, and what all am i looking for(part wise).

This is my first bike so your experience is greatly appreciated.

jplata wrote:

Ok, I posted earlier that i was having issues with getting my electric start to work. Now for some reason the kick start will not work. The engine turns over but will not start. I have tried checking the plugs and all the external stuf that could cause a starting problem. I am ready to tear into the engine but I would like some advice on where to start the troubleshooting. I have purchased a service manual. Please advise with any help or if you need more info to diagnose.

Thanks

Put a timing light on it and see if it is sparking while you kick it over.

Check the compression.

check plugs to see if they are wet (getting fuel).

I have a 750 twin and I don't know why anybody would want to kick it. Mine is a bear to kick over. BTW, I saw two rebuilt starters for 750T on ebay last week, one sold for about $50.

I like kick starting mine, not many people see that happening these days:cheer:

I started mine yesterday for the first time this season. Opened petcock and let it sit for 20 seconds or so, set choke to full and it started on third kick. Outside temp was in the low 60's and last seasons gas in the tank. Can't say that I would even bother to fix the starter clutch, maybe if I have nothing else to do, but that won't happen around my house:woohoo:

Yeah i really do not want to attempt to rebuild the starter clutch. I think i will take Steell's advice and check the points, plugs, timing, valves etc. I really hope this works to get the kick start working. We are having great riding weather. If i can get the kick start going i can put off fixing the electonic start issue for another day.

I have a bad battery in mine, so I have to kick start it when it's cold, but when it's warmed up the electric start will start it (starts in less than one revolution warm).
I replaced the shocks with a pair off a low mileage 750E, replaced the tach cable, and finally got around to syncing the carbs with a mercury filled carb sync gauge (got rid of that irritating popping out the exhaust), and took it for a test drive to see my brother. Shut it off when I got there and started it when I left an hour later. Eased the kickstart down till I got the pistons past TDC (about halfway), then kicked it the rest of the way down. Bike started instantly, on half a kick.

Parts needed for electronic ignition conversion:

Igniter, Timing advancer, Pickup, and that's all you need, but it helps if you can pick up a KZ440 wiring harness cheap to get the four wire square connector that plugs into the igniter.

I mount the igniter under the right sidecover on the airbox, just because it's convenient.

Everything bolts on, takes maybe a half hour to do the conversion. I have done three or four, and have enough parts left to do one more. The parts used to be cheap on eBay, until I started spreading the word, first time I did it the parts cost me ~$25, last time it was ~$90

My bike is a mongrel, assembled from parts off several different bikes, 79 frame, 82 motor, 80 body parts, 79 1000 front disks, 83 GPz750 front brake calipers, 95 GPz1100 front master cylinder, NOS Morris Mags, 81 750E shocks, Superbike bars, 83 GPz750 shifter linkage, homemade rearsets, various other parts from my collection of spares. Once I put a 17 tooth front sprocket, Mac 2 into 1 exhaust, and a windshield, on it, it will be just the way I like it.