Hey Chaps, The '78 750 Won't Reliably Start. Looking for Advice

[78_KZ750_Cafe]

Hey guys, it's been a long time since I've had to ask for help, but I'm at the end of my rope here.

When the bike runs, it runs strong as hell - no sputter, strong acceleration, normal idle, no excessive fuel consumption. But that's the problem, when it runs.

For the last two-ish years i've been kick starting the old girl with no trouble (because i like kicking it rather than using the starter), with a yearly tune up and points adjustments she's been ultra-reliable. But when I pulled it out of storage this year she's been a real b*tch about starting reliably. I've gapped the points dozens of times, fresh gas, gapped spark plugs, all voltages proper, charged battery, both cylinders pull 130-135 PSI on a compression test, spark plugs get wet when kicked over, plugs show spark when laid on the block... I don't know what else to check out or adjust.

It WILL start when the battery charger is hooked up to the battery and the engine gets kicked over, leading me to believe it might be a weak coil, but that's based on nothing. Anybody have ideas?

Also, i'm tired of points and condensers. Anyone know of a reliable way to convert these old birds to electronic ignition? There are some defunct suppliers out there, but the parts are worth solid gold now. Looks like a DIY unit is necessarily.

[DrKayak]

On my 900 I replaced the coils, plugs wires and did the relay mod to power the coils directly from the battery. It starts instanlty. I have comuted on it all winter with never a starting issue. It does have electronic ignition.

On my 750 I replaced the points, coil, wires, plugs and did the relay mod before I ever tried to start it. It started on the first kick till I tore it back down to replace the head gasket and starter clutch. Time will tell if It will be as perfect as the 900.

If you are running on the OE coil I would get a new Dyna w/wires and do the relay mod. It's a $10 mod that can't hurt.

[78_KZ750_Cafe]

It's definitely not a stock ignition system. I've got normal points and a condenser under the dome, but that's all that's original. I've got a hot coil from JC Whitney, fiberglass core ignition wires and NGK plugs.

Please expand upon this relay mod you speak of.

[DrKayak]

Here's the relay mod:

wiredgeorge motorcycle carburetors - Vintage Japanese Motorcycle Carburetor Sales, Rebuilding and Restoration - Repowering Ignition Coils To Get Full POWER!

Another possible source would be the carb getting dirty over time. I would think this would show up as needing more and more choke to start. If It's not starting at full choke this could be it.

My 900 starts needing extra choke ever now and then. I found running a tank with a strong shot of Sea Foam bring it back to normal.

[herk]

The 80s 750-Twins have electronic ignition & share most the ignition parts w the 80s KZ440-Ltds; you'd need the timing advancer from a 750-Twin.

[StarGate]

If it's starting ok when the batter charger is connected, I'd suspect the battery may be on it's way out or a low coil voltage due to old/dirty/corroded connectors in the ignition/coil power circuit. The coil repower mod is a nice fix, I did it to mine several years back.

[King David 72]

Berryman CHEMTOOL B-12 bro. Put it in the gas, and continue to try to start your bike until it does. 2 ounces per gallon instead of 1 though. That old bike just 'aint used to this new gas. Your jets are dirty because the gas formulation that is used nowadays goes bad quickly & easily. Good luck.