New member from MN

[ArfBrookwood]

Well this week was the first time I had trouble with the bike as it lost power on the freeway. Towed it back to my garage. battery was incredibly weak so I suspect the stator. Joined gz250bike to looks for suggestions if my best efforts fail me. Been commuting for a couple years, and I'm a big fan of Aerostich, as my suit came in handy when I hit a deer last year. Both the deer and my headlight were injured, I was fine. Thanks for what looks like a wonderful and supportive community of riders. Looking forward to learning more.

[Vegas Street Rider]

Welcome to the forum. Hope you get it figured out on the power loss. As you already know, ATGATT.

[Axeman88]

I'd give the battery a good charge overnight with an auxiliary charger, then make the following simple test.

At least three hours after I had fully charged the battery, and removed the auxiliary charger, I'd hook up a voltmeter to the battery + and - terminals, and take the following readings.

- The voltage just sitting, with nothing turned on, will show me the state of charge and/or condition of the battery.
- The voltage when I switch on the ignition and headlight comes on, is also of interest.
- While holding the start button in to crank the engine, voltage will drop to some lower value.
- Finally, after starting, and running fast (~2000 rpm) with the choke on, the voltage should rise to its highest value.

From these numbers, we can tell a lot about the battery, and the charging system.

[ArfBrookwood]

I have a voltmeter but have not tested the battery with it yet. The bike is on a charger and has been since Monday. It turns over but there seems to be no "ignition" sounds. And it seems to lose charge VERY quickly. As soon as it lost power on Monday I pulled over to the side of the road as AS SOON as I pulled the clutch in it INSTANTLY died. No juice to even try to restart it. So I kind of think it has something to do with electrical, but even at a "full charge" it does not start. Anxious to try a new spark plug tomorrow, though, and continue on my journey of learning.

[Axeman88]

Originally Posted by ArfBrookwood

The bike is on a charger and has been since Monday. It turns over but there seems to be no "ignition" sounds. And it seems to lose charge VERY quickly.

Don't overcook your battery. The battery on a GZ250 is small and shouldn't be charged at a very high rate, no more than 1.2 amp max, and 8 hours of charging should be enough time under almost any normal conditions.

Does the battery have enough electrolyte? Wet batteries need to be maintained, by keeping electrolyte level up to the line. I find I need to check level, on those machines that have wet batteries, at least three or four times a year and add a little distilled water. Charging can boil off the water, even while riding, and if the plates are exposed, crystals can form that short out that cell, at which point the battery is done.

If you can't get the machine started, you can't test the charging system. Personally, I'd avoid jumping the motorcycle, because it's hard to use those big car jumper clips in the tight battery compartment of a motorcycle, and a mistake can damage electronics, or worse. What I do instead is to temporarily replace the motorcycles battery with an extra general utility car battery I have available, using heavy cables with lug ends and sections of bicycle inner tube to insulate those. With the car battery, I can crank and test, for hours, without running down my bike's battery.

I'd anticipate looking for a new battery. I put one of these in my GZ250, a year and a half ago. https://batterysharks.com/suzuki-250...placement.html
For $14, one shouldn't expect the highest quality, but I'm happy to report it's still going strong, a year and half later. And, this one is a sealed type, so no maintenance is required. Max charging rate is still relevant.

[Vegas Street Rider]

Regarding batteries, I spent the extra cash and bought a lithium ion unit for my GZ. That was 5 years ago and it hasn't missed a beat. They are pricey though. I believe I paid about $120 for it. Probably more now

[ArfBrookwood]

I carry my tender with me in case of these issues and that's what I put it on. Tried to start it yesterday with a new spark plug and some starter fluid, and there was plenty of charge, but no change from just the typical starting noise. I will try more things this week. I am just glad that I am in no hurry and have another vehicle to drive while I read up on things.

[Axeman88]

One thing I've experienced, that may be relevant, is that ICMs (Ignition Control Module) generally have an internally programmed threshold, below which they will not create sparks. This is right around 10V. If system voltage goes below that value, ignition doesn't work, so a bike with a high resistance battery, or one with a bad cell, may still crank but won't fire.

Lead Acid technology in small motorcycle batteries generally last 3-5 years, on average, but can fail much sooner if something is out of whack.

[ArfBrookwood]

Finger test over exhaust/spark plug hole does not get blown off. Trying to think what would cause it to lose all compression.

And I get great spark.

[Axeman88]

Originally Posted by ArfBrookwood

Finger test over exhaust/spark plug hole does not get blown off. Trying to think what would cause it to lose all compression.

Intake or exhaust valve not closing or not sealing?
Broken Piston ring?
Hole in piston from sustained pre-ignition?