Battery Charging problems on 2 stroke slut

[Micmac]

Hello couple of months ago I decided to buy 2 stroke Aprilia rs125 1998 model. The first 10 -12 times starting it was no bother. After a week I started noticing it became harder and harder to start her so I changed the battery and sparkplug, still i would try and start it but that only drained the battery until the dash lights flicker and turn off.
Still the problem persists. It starts up real quick when jump starting it. So the only conclusion I can come up with is it’s not holding charge for some reason? Like I rode that slut for 3 hrs after jump starting and still she decides not to start after 12 hrs.. I took it to 3 mechanics. None of them saw a problem with the battery or the alternator. So I just give up and I’m looking to purchase a portable battery jump starter that I can just plug in to eyelet cables that are going to be attached to the battery terminals permanently.
Is this a good idea? And can any of you provide me with a good jump starter that isn’t too big.
Thanks for reading. I love you.

[doggone]

Does it start OK when it's run a while and is warm?
Your 'solution' sounds impractical you can get what's called a battery tender lead with a safe plug on the end and leave it on trickle charge if possible when not used for a few days.

Something else is going on though by the sound of it, a multimeter would be useful to check some readings on the battery after charging, before charging and while trying to crank the motor.

You could have a sluggish starter motor which is having problems turning the engine over fast enough and draining the battery far quicker than normal.

It could be a bad earth, sounds like you have jump leads so attach one of them from negative terminal to a bright spot on the frame, and see if things seem any better - again a meter would be useful.

Electrical problems are common on older bikes as connections corrode and components can fail or partially fail in a variety of ways.
It's not rocket science though and most things that go wrong can be resolved at modest cost.

[davebike]

Did your three mechanice check the battery with a battery tester? Did they check the charging vltage?

My suspition is one or both essential checks were missed!
____________________
Dave
NC750Xdct + others at work !
davebike1@gmail.com

[stevo123]

Could be

battery
charging system
parasitic drain.

To check charging system:
Run the bike, raise revs to around 3k and check voltage accross battery, needs to be around 13.8-14.5v (thanks davebike)

To check for a drain:
Put a multimeter on AMPS inline with one of the battery terminals to check for "leaks". If you see a current flowing then pull fuses until it stops. Check circuit diagram for what is on that fuse and you will be closer to the problem.

[davebike]

[stevo123]

[doggone]

A simple test for charging or not is hold something in front of the headlight and blip the throttle, you should see a slight but distinct increase in brightness as you come off idle (useful if buying a bike too).

[steve the grease]

When I started mechanicing I rapidly came across what I have called 'The starting circle'.
Vehicle won't start, so is it
A forked battery?
A forked charging system?
A forked starter?
And how to prove what is defective.
If it will start on a jumpstarter then its not the starter , so now we are down to 2
Ok the battery is flat , is it flat cos it's fucked and its lost its charge or is it flat because it's not charging up.?

Charge the battery up off the vehicle, then try and start the bike. Probably it starts. leave the battery overnight and try again, if it struggles or is dead then for sure it is the battery that that is at fault, a good battery will hold it's charge for months. A cheapish battery will last maybe 3 winters in use, by the forth it's tired. Especially at this time of year an older battery is suspect.- cold weather slows down chemical reactions.

Another test , with the suspect battery in place use the jumper to start the bike, check the voltage - * if the battery is no good, it will rapidly come up to about 14 volts, this proves 2 things - that the charging system is working ok, and that the battery is knackered as it appears to reach full charge so rapidly. If however the charging voltage never gets over 12 ish volts then its the charging system, that is the problem.

An analogy :
Imagine a battery is a water tank, like in your loft. A good battery is like a tank full of water, lots of useful capacity. A knackered battery is like a water tank full of mud except the top 2 inches, which has water laying over the mud . When you turn on the tap , the tank very rapidly runs out of water... when you try and refill it , it reaches the full level very rapidly , or at least appears to, because it no longer has any useful capacity. " Hey this must be a good battery , because it charged up so rapidly" Sadly no.

* https://www.ebay.co.uk/itm/Digital-Battery-Alternator-Tester-12v-LED-For-Car-Van-Motorbike-Vehicle-Small/392314387879?epid=28037885052&hash=item5b57c27da7:g:SPUAAOSwUrNdoQZ8 Dead Handy
____________________
All the above is my personal opinion, you can see my lips move, but I'm talking out of my arse.
I've been riding, and fixing , bikes for 50 years, in that time the more I learn, the less I am absolutely sure of.....