Charged dead battery, installed, blew fuse.

[seanmhc]

I'm trying to get my head around what just happened.

So my SV wouldn't start, the previous owner said there was something up with the battery, it runs fine after being jumped. The ignition came on fine but once I hit the starter motor it tried to crank before everything stop and the dash lights went off.

Me being me thinking I knew exactly how to solve this decided to take the battery out and attach it to charger.

Now I left it attached to this 6A charger for about 30 minutes when it told me that the battery was fully charged. I thought great, let's fit it back in the bike.

Put the battery back in, turned on the ignition which worked fine but this time I hit the start button... BANG. Then everything died. Now turning the key has no effect.

Now it's obvious that I've blown the main fuse, but I don't understand how?

Being a new bike to me and me maybe slightly lacking in the mechanical side of things.. I'm just going to ask.. How do I fix this and get the bike working again?

I feel like such an idiot and having very little money to play with I'm only able to fix anything on the bike in my own garage, I just can't make sense of what happened in my head.

[squirrel_hunter]

The simple answer is a short somewhere. The question is where...

Firstly, do you have a supply of main fuses, these might be handy?

Secondly, have you got the battery round the correct way (yes I have seen this before)?

Third, which model SV have you got?

[seanmhc]

Soon as the shops open this morning I'll head out and get myself some. They're 30a fuses am I right?

Unless my eyesight is failing me for some reason I'm 99.9% sure I connected it up the right way, I will check in just a moment once I get outside, I can understand why you'd ask though!

The bike is an SK5.

[maviczap]

Terminals go to the rear, that's the way the battery sits in the tray. Positive on the left,

[seanmhc]

Battery round the correct way - Check
New fuses - Check
New Battery ready to go - Check

[Red ones]

Terminals go to the rear, that's the way the battery sits in the tray. Positive on the left,


Unless the previous owner changed it for a slightly unusual glass mat battery which has terminals on opposite corners. Then it's not so straight forward and very confusing.

Luckily I had a set of 30A fuses spare.




I'd go looking at cables that may have rubbed on the frame as a starting point.

[maviczap]

Aye, mine has got a motobat battery on it, with 4 terminals, so could confuse.

[seanmhc]

The only thing I can think is that it's somewhere near the terminals as it only happened once I'd taken the battery out and replaced it, before it happily tried to start, so I'll go have a look. Time to figure out how to take off all these rear fairings

[seanmhc]

So I replaced the fuse, and installed the new battery, woo the bike starts! I thought I'd take it round the village to give it a little test, managed to take the bike down a few streets but every time I was getting to a junction and knocking it into first the engine would cut out, and each time I started it the bike seemed less and less like it wanted to come to life. Hmm is this just due to a lack of charge in the battery?

[squirrel_hunter]

I've seen something similar on one of my bikes. It was a faulty reg rec.

My first suggestion is to test the charging system. There's lots of tutorials on her to help. Do that first and report back...

[seanmhc]

I had to rush off to work and leave the bike how it was, but I did end up having a small look into regulator rectifier issues on my break and it seems like a good place to start.

I know the previous owner had been jump-starting the bike to ride it and I've heard that doesn't do much good to the reg rec.

I'll let you know how it goes tomorrow morning when it's light. Thanks very much for the pointer!

[Geodude]

If you have or can borrow a multi meter follow the guides in my sig, very easy to do and must be as i could do it ;)

[seanmhc]

So I followed the rectifier test with a multimeter in diode mode and everything seemed within specification. Hmmm

[andrewsmith]

Crank it over with the battery connecter from the reg rec off and voltage test it. It's how I found mine was goosed

Sent from my E2303 using Tapatalk

[seanmhc]

Thought I'd run by and update you all on the situation.

I put back in the regulator/rectifier connected it up and took readings across the battery terminals at off, idle, 3k rpm, and 6k rpm: (Respectivly) 12.96V, 12.80V, 14.4V, 14.3V

I've noticed that the issue of the bike stalling happens only once the engine is warm and I've been out for 10-15 mins. When I pull in the clutch the revs drop below idle and the engine cuts out. I dared to put the bike into neutral by gently lowering rpm when at lights to see what happens and the idle is not steady, the needle fluctuates by maybe 400rpm between 1400-900~. Bike tries to idle at normal rpms but seems to settle just a smidgen over 1k but it's obvious it isn't happy.

I'm tempted to look at the spark plugs, and maybe adjust the idle a little higher (it's around 1300 right now) - but I feel that would be just avoiding the problem rather than figuring it out. If anyone has any clues, please let me know.

[seanmhc]

So after winding myself up not having a clue what the issue was, it cleared up today.. coincidently when my fuel light started flashing.

I also got a message last night from the guy who sold me the bike saying that he didn't have any issues with the bike stalling, but that the bike had been stood around for a long time.

2 and 2 together, the fuel left in the tank must have gone stale and crudded up, and as soon as the auto choke disengaged the fuel was getting clogged in the injectors and causing the idle to be really unstable. When I'd got the bike I put in about 5 litres of fresh fuel ontop which is what must have been left in the tank.

Filled the bike up with a full tank of fresh petrol and been riding it all afternoon to see if it started stalling again, even when it got up to temperature the idle has held steady!

Looks like I didn't buy a lemon! All the bike needed was a new battery and a fresh tank of fuel.

Thanks everyone for your help!

[Toooldtodie]

Happy days!
Every day a school day, and you've just started to find your way around the bike.
Good detective work btw!

[seanmhc]

Happy days!
Every day a school day, and you've just started to find your way around the bike.
Good detective work btw!

Thanks very much!

You have no idea how relieved and happy I am to have it sorted and for the bike to be running happy! (Bonus that it cost me nothing more than a battery and a few cheap bits and bobs)

Should be much easier taking the bike apart to service / fix any future issues, haha!

[Craig380]

Good that you got to the bottom of it.

And verily, it is written that 90% of ignition problems are caused by the carbs / injectors, and 90% of fuelling problems are caused by the ignition ;)