RC51 won't start

[SwiftTone]

First time riding this season I went out for a 2 hour ride. Stopped a few times and it didn't have any starting problems. Finally I went back home to pick up my gf. Had the RC parked for about 10 minutes, when I went to crank it, it was a really weak and would only turn 2-3 times until it starts clicking(solenoid??). Ended up parking it and hooking the battery up to a battery tender.

I charged it over night and in the morning when I took it off the charger it read around 13.6V. It would drop to 13.07V in about 15 min. When I got home from work at 10PM, the voltage has dropped to 12.98V(I'm assuming this should be a good voltage after the battery has rested.) So I did some measuring this morning. Started with a rested battery at 12.98V. When the key is on with low-beam on the voltage reads 12.2V. When cranking the battery will drop to around 10V and immediately go up to 14.5V while warming up. Once warmed up, the battery measures 14.6V at 3000rpm and under 15V at 5000rpm. This should indicate that the charging system is okay right?

What do you guys think is the issue and what should I check next?

Thanks

[JohnnyV]

Regulator/rectifier would be my guess

[nt650hawk]

I'd replace the battery.

[Sheppo]

what gino said. If it is charging correctly, which it seems to be, the Reg/Rec are ok.

[NobodySpecific]

Regulator/rectifier would be my guess

Not with measurements like those. A good R/R will output somewhere around 13-14.5 V.

I'm with Gino in that my guess would be the battery.

[drop]

poor/loose battery connections would be the first thing i'd check. could be a bad cell in the battery too, which can cause intermittent (and heat/vibration influenced) power issues.

[NobodySpecific]

poor/loose battery connections would be the first thing i'd check. could be a bad cell in the battery too, which can cause intermittent (and heat/vibration influenced) power issues.

I actually did have this happen on my SV. Riding around on a week long trip and everything was going smoothly. We stopped to take some pictures and suddenly the bike wouldn't start. Couldn't get it to bump start either. Finally decided to check the connections and sure enough one of the cables was loose. Tightened it up and the bike fired right up.

[SwiftTone]

Can you guys explain to me why it would be the battery if it only drains from 13.07V to 12.98 in the course or 10 hours?

When I go for a ride for 1 hour, and let the bike sit while its off for 10 minutes and it can't restart, does that mean I was when I was riding around, the stator was powering everything? I mean, if the charging system is charging the bike while riding, why would the battery be dead when I go and start it? I'm just trying to make sense of this.

Thanks

[jasnmar]

Batteries can be weird.

Depending on the exact construction of the internals there could be a plate that has "broken off". At some points it might be in the right position. At other points it might get bumped into the wrong position, and cause a particular cell to short.

I'd start by making sure all the battery and ground connections are good.

Next "most obvious" target is the battery. How old is the battery? In the "do as I say not as I do" theme replacing them every 4~5 years isn't a bad thing anyway.

R/R could be at the right voltage, but may not be producing enough current.

Before all of the electronics this was a much easier task, as you could simply pull the battery. If the vehicle kept running with headlights and all the accessories on, it was probably the battery, as the charging system was working.

[ZX11D]

Battery or connections . Bring it in to Autozone and have it load tested.

[SwiftTone]

Battery or connections . Bring it in to Autozone and have it load tested.

They told me they won't test motorcycle batteries. I went to 2 stores. Thought it was really weird.

[Kurlon]

They told me they won't test motorcycle batteries. I went to 2 stores. Thought it was really weird.

They likely don't have a small enough load tester. Put something expecting a 1000CCA battery on a wee widdle bike battery and the lead will flow out the overflow before you realize what's wrong and shut it off.

[scubasteveRR]

it's broken, throw it away, actually even better i'll take it off your hands for free.

[NobodySpecific]

If you are convinced that it isn't the battery, have you added any electronics recently? Are there any aftermarket electronics on the bike? I suppose it is possible that there is a soft short to ground (meaning there is sufficient resistance to prevent high currents, but lower resistance than ever intended). If that is the case then you are opening a can of gremlins that is very difficult to diagnose online. Whatever problem you have seems intermittent, which makes it hard to diagnose. Have you ridden the bike since? Have you left it off the charger for a few days? Do you have anything you can turn on to increase the current draw while the bike is running? Heated gear, aux lights, cell phone charger, anything.

[SwiftTone]

You guys convinced me so I ended up ordering a Alien Motion 8 cell lithium battery. Figure I should start there as I don't know the age of the battery anyways. I should get it by Friday and go for a shakedown on Saturday. Will keep you guys posted!

[GTStang]

I can tell you with my RC51 it started out as it I would only get 2-3 attempts to start then it would be too weak to start. Checked the cables and connections reconditioned on my CTEK and would be good for a while then if I let it sit days only to find a couple good starts then dead. Finally got to the point where I could ride a few hours turn it off and it wouldn't even try to start. Didn't check voltages just bought a new battery cause it was cheap and I had the one that came with it when i bought it so decided to remove that piece of the puzzle. Have not had an issue since have let it sit all winter hooked up to bike with no charging inbetween the last two and cranks strong and no problem.

[golden chicken]

A properly charged battery should measure 12.7V at rest. Anything above that is basically a residual surface charge. Using a multimeter, as you did, to check the voltage while the bike is cranked, the cutoff is 9.6V. That is, if you start with 12.7V and crank the bike and it drops below 9.6V, the battery is dead. Having it drop to 'around' 10V makes me suspicious of the battery as well.

If a battery dies a certain way, it can show a high surface charge, but not actually have any real capacity. Sometimes you can charge a battery to 15V static, but as soon as you load test it, it drops to 0.

[Degsy]

Wirelessly posted

You guys convinced me so I ended up ordering a Alien Motion 8 cell lithium battery. Figure I should start there as I don't know the age of the battery anyways. I should get it by Friday and go for a shakedown on Saturday. Will keep you guys posted!

Not to piss on your parade, but I have experienced and heard too many problem stories about these new battery technologies for me to get one just yet. I would get so pissed off by the whole "try to start the bike 3 or 4 times until the battery warms up" bullshit.

[mycirus]

The RC needs a strong battery to start. I had the same issues with mine back in the day and replaced it and was good to go.

[RandyO]

Once warmed up, the battery measures 14.6V at 3000rpm and under 15V at 5000rpm. This should indicate that the charging system is okay right?

What do you guys think is the issue and what should I check next?

Thanks

How much warmed up?

I have seen intermittent RR failures, work well while engine is cold but after 45mins or an hour of riding, heated up enuf for the semiconductors in the RR to fail, after it's cooled down, it will test ok again

[jwm2k3]

Dave, bring the battery to Parkway Cycle, they will test it for you. Besides, a motorcycle charging system wont charge a battery at idle like a car will.

Hey, its an opportunity to get one o them fancy Shorai lithium batteries. A big twin like yours would LOVE a Shorai battery!