Electrics died. Just a shagged battery?

[3-Max]

What happened ('98 Canadian trike).
3 1/2 wks ago was running sweet. Went for a ride. Rthnd rear mudguard bracket snaps & nearly loose the thing but get home safely. Stands 2 wks in the garage. I weld the mudguard back on taking care to disconnect the Bat earth lead as usual. Start it up but it sounds really rough like missing a couple of cylinders. Let it warm up & things improve. Take it to petrol station at the end of the road to fill up. While maneuvering to get next to the pump, engine cuts as it looses all electrics. Not even the hazards work. Measure Bat voltage before towing home - showed 12.6.
After disconnecting & testing everything I can think of. Did the tests in Haynes maual for the stator & this seemed OK as did the ignition & switches, starter cut off relay. I can get the ignition to light stuff up, cycle the V-boost servo & fuel pump but won't go near turning over. Assumed battery was shagged. Was still showing 12.65V but sometimes this drops to 7 or 8 for no apparent reason as soon as I turn the key, even with all the lights disconnected. Switch off & on and back to 12.6 or not. Have jump started from a running car delivering 14.3V. Sometimes this sounds good sometimes slightly off. Doesn't particularly like starting like it did. Need 2 - 3 attempts.

Ordered a new battery which should be here Weds (no idea how old the current one is but given the state of the rest of the bike it's more than 5 yrs old).
Have just tried another jump start & still sounding just a tad off. Disconnected the car so as to measure the Bat's V's while running on it's own. Soon as I did that instant change in engine sound & was running really rough again - not surprised as measure voltage was 4.5 V across the terminals. Bouncing about a bit but only by c. 0.5V.

Thoughts please as I'm just about ready to throw in the towel.

 

[Fire-medic]

Relax, don't do it (trying anything which vexes you).

Wait for the new battery. Electronics like the engine CDI don't like 'off-voltages' or 'way-low voltages.

 

[3-Max]

New battery has arrived 1 day early, yay (atom-AGM 16AL-A2 12V 17amp maintenance free gel). Showing 12.6V - does this need charging ? I'm thinking 13V+ more like full charge.

 

[Fire-medic]

It probably is OK, but traditional charging practice to help a new battery live, is to charge it on a trickle charger at no-more than 10% of its rated ampacity (amps) for say, 6 hours. Practically-speaking, just don't use the 'boost' setting if you have a more-powerful charger. Choose a 2-3 amps charging rate, and that should be OK.

 

[one2dmax]

12.63 volts is 100% charge for the standard 12V auto/motorcycle system. 2.1volts give or take per cell. Side note, 12.43 is considered the industry standard for fully discharged though most of the time they will still crank and start at lower voltages then that.

 

[3-Max]

So - to answer my own question. Yes, battery was frelled. Gave the new one an hrs trickle charge which got it to 12.9V. Fitted it this afternoon & everything works & engine sounding very health. Getting 13.7V across terminals idling at 1K. All lights much brighter too. Clearly that old battery wasn't in good shape when I bought the trike. Just shows how long it is since I worked on a vehicle. Not used these fancy new electronics.
Thanks for the input fellas.

 

[Fire-medic]

Good news, sir! Ride safely.

 

[3-Max]

Well that was short lived. Took it for 15 mile spin to make sure everything was in order - Rode lovely but now have the frnt lft fork leg leaking oil onto the brake caliper, disc & the tyre... This is pretty much all it's done since I bought it a yr ago. Fix one thing, develop another straight off.

 

[Fire-medic]

Patience is a virtue, yes? Just work through things as you encounter them and set them right. Many times, the reason a bike, car, truck, whatever is 'on the market' is because of deferred maintenance. Each owner besides the original purchaser faces repairs, and they can do things right, look for a cheap fix (usually short-termed) or ignore the problem and if possible, use the conveyance until it stops working or it becomes unreliable, you know what that means: "for sale, "ran when parked."" You may be the latest owner playing 'catch-up' with prior owners whose use/abuse whose willingness to pay was exceeded, so it went on the market.

I have a suggestion for you. Do both seals when you do the leaking one, and I suggest OEM seals for the replacement. They will last the longest.

Another thing, carefully examine the downtubes for any chips in the hard chrome. If you find them, it's useless to replace the seals, as they will soon leak as the sharp edges of the broken chrome will tear the seals apart. You need to replace the downtubes. I've never seen a case where a local chroming shop can re-chrome the downtubes for less-than what new ones cost. Seeing you're in the UK, that may not be true, but I suspect it is true there as well. Here is one USA resource I've used.
https://franksforks.com/and YAMAHA FORK TUBES BY FRANKS FORKS

Another resource: RT - Digital Product Search

exactrep in the U.K. probably has downtubes. Yes, they do 220 pounds including VAT, each, for the 43mm size. Cheaper by quite a bit over the OEM. That's a difference of 68 pounds/$82 apiece from USA OEM. That looks like the best bet for new product.

An alternative: look for a used pair. If you cannot view them in-person, your ebay U.K. or social media pig in a poke may turn-out to be just as-bad as what you now have.

Just to see what the USA OEM pricing is I checked for your size 43mm downtubes: $361 apiece. Part #'s 8 and 29.
https://www.ronayers.com/oemparts/a/yam/500434bef8700209bc78bb52/front-fork