weak spark >> dead bike

[Anonymous]

First a little history. This '78 GS1000 has been my proud possession since November 1989. Since the beginning it has been VERY hard to start (had to crank for 5+ minutes) but ran ok once it was going. Recently the engine has been rebuilt and the carbs disassembled and cleaned. Was running good, but still hard to start. About a week ago at about 40 mph the bike quit and refuses to start.
Both of the coils have a weak spark. Had them tested at the dealer and the coils are ok. Just checked the supply voltage, and there is 10 volts to each coil. When the starter is turned, the voltage drops to <8 volts. Hooked my voltmeter between the ignition fuse and the negative battery terminal and read 13 volts with the engine kill switch off. As soon as the kill switch is turned on the voltage drops to 10 volts. Is this normal?? Would really appreciate any help.

[Anonymous]

Re: weak spark &gt;&gt; dead bike

First a little history. This '78 GS1000 has been my proud possession since November 1989. Since the beginning it has been VERY hard to start (had to crank for 5+ minutes) but ran ok once it was going. Recently the engine has been rebuilt and the carbs disassembled and cleaned. Was running good, but still hard to start. About a week ago at about 40 mph the bike quit and refuses to start.
Both of the coils have a weak spark. Had them tested at the dealer and the coils are ok. Just checked the supply voltage, and there is 10 volts to each coil. When the starter is turned, the voltage drops to <8 volts. Hooked my voltmeter between the ignition fuse and the negative battery terminal and read 13 volts with the engine kill switch off. As soon as the kill switch is turned on the voltage drops to 10 volts. Is this normal?? Would really appreciate any help.

The 13 volts on the battery is good. The 10 volts on the coils seem too low. I never checked what happened to the voltage level on my bike when I hit the starter. I just went though a bunch of electrial trouble shooting on my bike. At lest it sounds like your battery is good. I had do redo the wiring from the ignitor to the coils to solve weird intermittent performance problems I had. ( I hope their solved!) I would do a search on ignition or ignition coils. I would guess you have some conductivity problems in your connectors or wiring.

[SqDancerLynn1]

Check the ign switch with your volt meter

[LW_Icarus]

I wired a relay into the ignition circuit to fire the coils with battery voltage, I too had ten volts, now its 13+. it was relatively easy if you think you can do it I can help out with any questions.
All you need is an "X" relay, with 4 poles, available inexpensively from any auto parts store.
try a simple test and run a wire from the positive terminal on the battery to the positive terminals on the coils. see if it fires up and runs. be prepared to put some new plugs in it, they may be fuel fouled by now as well.

[mark]

I went through my bike and cleaned every connection I could find, from the starter switch and handle bar kill switch to the battery ground, fuses, fuse box etc. Ended up with another .7 volts. I think it helps.