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Discussion Starter · #1 ·
Hey guys!

Once again, I appreciate any and all help with my questions. Here it is:

My 1981 Yamaha XS850 Kickstarter/Battery and how it relates to the ignition.

Not sure what type of ignition my bike has, TCI, or CDI?(can someone explain the functional different?

-Running stock ignition system
-Using a Ballistic EVO 2 8cell battery

Picked up my bike from the shop, with a fully charged battery it kicked over no problem. It's been sitting for a few weeks since I have not had time to ride and just been detailing and polishing it for now. Now when battery is low/dead it won't Kickstart...

Does my XS850 need a Battery to use the Kickstarter?(I didn't think it did?...)

My current battery is not strong enough to start the bike with the start button when it is cold, why? Do I need a stronger battery?

Thanks again!
 

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Yes, you need a battery to start the bike. You have to have battery power to send the current through the coils that makes the spark. Some bikes create spark with a magneto, but I doubt yours does, without searching for the wiring diagram.

BTW, a TCI uses transistors in place of the points in an older system; the transistor grounds one terminal of the coil, charging it with current, and when the transistor turns off, the spark is released. A CDI (capacitor discharge ignition) is far less common, because of how it works. An oscillator charges a capacitor to about 300V, and that charge is dumped through the coil to make the spark. Because of the high Voltage and other design issues, failures are common, so even though they made for quite a strong ignition, maintenance became a problem.

In either case, most ignitions of either type need at least 10V to generate a spark at all, and more than that to fire a cold engine.

Sitting for a few weeks should not have killed the battery; it surely would not if you had an AGM type. Do the lights come on? If not, did you leave the key switch in the P position (engine off, tail lamp on)?
 

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Discussion Starter · #3 ·
Yes, you need a battery to start the bike. You have to have battery power to send the current through the coils that makes the spark. Some bikes create spark with a magneto, but I doubt yours does, without searching for the wiring diagram.

BTW, a TCI uses transistors in place of the points in an older system; the transistor grounds one terminal of the coil, charging it with current, and when the transistor turns off, the spark is released. A CDI (capacitor discharge ignition) is far less common, because of how it works. An oscillator charges a capacitor to about 300V, and that charge is dumped through the coil to make the spark. Because of the high Voltage and other design issues, failures are common, so even though they made for quite a strong ignition, maintenance became a problem.

In either case, most ignitions of either type need at least 10V to generate a spark at all, and more than that to fire a cold engine.

Sitting for a few weeks should not have killed the battery; it surely would not if you had an AGM type. Do the lights come on? If not, did you leave the key switch in the P position (engine off, tail lamp on)?


Thanks a bunch for the info!

The lights did not come on, the battery seemed to be fully dead. I left the key in the off position, left everything in the off position. Perhaps the battery is slowly losing power from somewhere?

What is an AGM type?
 

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Well, lithium batteries can lose power through self-discharge; the ones in that battery pack should have a fairly low rate, but can die from lack of use. A few weeks seems like too little time. You may be able to charge that battery with a low-current charger, say 1-2A, but you'll have to read up on charging that battery from the maker. If it charges, or if you have another 12V battery you can sub in (it doesn't have to fit, and can even be from a car or truck), I would use a cheap Voltmeter in Amps mode, and connect it between the battery negative and the mating terminal, with the key in the off position. Begin with the meter set to the highest Amp setting; it should remain at 0.0 as you select the lower settings, but if it doesn't, you need to find the leak.

AGM stands for absorbed glass mat; it is functionally the same as a standard flooded lead-acid battery (the kind you add water to), but between the lead plates is a fiber mat soaked in the acid. This allows for more pure lead, because it doesn't have to support itself as much, and that leads to longer life and higher discharge rates (think starter motor). They are sealed, but are not the same as SLA (sealed lead-acid) type batteries, which are about the same as the standard type, but without a vent. Of course, you don't save the weight of a lithium battery, which doesn't amount to much, anyway, but your charging system is designed for lead-acid.
 

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Check under the seat. You should find an Ignition Control Module.
Get a volt meter and a battery maintainer. A good 12 volt battery should have 12.75 volts. It is half flat at 12.25 volts. Under 12 it may or may not turn over the engine. But I would think at 11 to 12 volts it should start with the kick starter. Below 11, who knows. Did you park the bike during the day? And did you turn the key all the way to the left. If so the tail light came on, and flattened the battery.

I use only regular lead acid batteries in my bikes, and my XS1100 always fires. Each bike has its own maintainer, and they are plugged in when not in use for a while.

UK
 
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