Honda CBF 125 losing power issue

[johng]

Hi All , 

 

I was wondering if I could get some advice , my Honda CBF 125 has been having some issues with losing power whilst riding. 
 

I can be going about 40 mph and the bike loses all power . When coming to a stop because of this it struggles to start , no power whatsoever . The neutral light fades in and out . And the engine management light comes on . 
 

I have had the mechanic look at this and after the first 2 inspections he said there was nothing wrong , as I managed to kick it back in before taking it in. Now it’s there again and will not start . He said it is showing battery fault , however when trying the battery on another bike it works , when trying to use leads it works , however when putting the battery back on the bike , same issue. His option was to put a new battery on , however this is a battery I have had since only April . I’m abit confused as to what it might be . 
 

any help would be appreciated. 

[Mississippi Bullfrog]

I'd start by cleaning the battery connections paying particular attention to the earth strap where it connects to the frame. A whole host of problems arise from poor battery contact and it's a very common problem.

 

Do you have a charger for the battery? Running it on the bike never gets it to full charge so it's worth investing in a good smart charger. I have CTEK chargers which are connected to my bikes whenever they are not in use. 

[johng]

Thank you @Mississippi Bullfrog il give that a go , and definitely thinking about a CTEK charger , never really had any other issues only this one , I feel the new battery will mask the problem , as it’s been ongoing for a couple of years but last time I had a new battery , and starter , but I don’t think they found the actual issue 

[onesea]

I would go with @Mississippi Bullfrog on check your earths.  
 

However I am not convinced about charging being solution. There is not reason a bike should not be able to be parked up for a month and not start on battery.  

 

Unless you only ride short distances.

[johng]

Would it still be possible that it is the battery even if this works on another bike and not mine? As the mechanic is putting me another battery on , and I’m not sure I need one , unless I’m mistaken? 

[Mississippi Bullfrog]

3 hours ago, johng said:

Would it still be possible that it is the battery even if this works on another bike and not mine? As the mechanic is putting me another battery on , and I’m not sure I need one , unless I’m mistaken? 

Unlikely,  though not entirely impossible.  I suspect its more likely to be a poor connection. 

 

People often misunderstand what I said about charging. The bike's charging system will keep the battery charged enough to start the bike, but that doesn't mean that the battery is kept fully charged. 

 

Many modern bikes have a low level of drain when the engine is off. With smaller bikes and low capacity batteries this can lead to partially discharged batteries making starting a bit marginal. For example,  my Honda has a battery monitor fitted and even with a high capacity battery it will show a reduced level of charge after 4 or 5 days if left off the maintenance charger. 

 

My Triumph has a lower capacity battery that most owners find fails after 18 months. Many have replacement batteries under warranty as they dont even last 12 months. These are Yuasa as OEM so decent batteries. Mine is 5 years old and still spot on. 

 

Both my bikes have monitors and are kept on CTEK chargers when not in use. It keeps the batteries healthy. 

 

So the suggestion to use a charger isn't saying that the battery charge is your problem. It is saying that keeping your battery charged using a decent smart charger is good for the battery in the long run. 

 

Some of my mates are always changing batteries. Mine usually last 8 to 10 years at least. 

[Fozzie]

Is it very sporadic? It just cuts out randomly at any speed/revs? 

 

As mentioned, check the earths. Its been several years since I worked on one, but I think there were two direct connections to the frame. And a large black cable off the negative of the battery connecting onto the starter motor bolt, but I could be muddling up my bikes, so I'd trace the cable and make sure its connection is sound and not overly corroded wherever it is. 

[johng]

I would say it cuts out particularly at high revs . And then completely loses everything . Then when trying to start complete silence, the only thing happening is the engine management light , and the neutral light however when you hit the electric start the neutral light dies , and fades back in when not pressed. 

[RideWithStyles]

Agree with the others to start with.

 

Yes so trying to start...but gives the impression of not enough juice to get it going if that was the case the headlight will be fairly dimmed too when turned on but before starting up But this would be more of a cold starting issue rather than a hot start.

something is masking the problem with the look of first cause at first glance. Plus needs to adress the cutting out in the first place.

 

the neutral lifht will naturally dim or go out anyway when starting it thats what they all do plus the engine light will stay on until started and idle. when it does this cut out and the key is turned does the bike make still sound of the pump being primed and other tick sounds at the clocks? Trying to think of the solution of hot starting issues...id look at the relays and its wiring too, if its weak, sticking, over heating that can give problems of cut outs and not starting.

Wifes cbf125 can stand unused and not on a charger for months on end, even after the snowy winter outside and still starts in april with a decent battery.i think after about more than 4 years like that its little battery did struggle and needed a second go to start it after its cold winter but after a ragging run it was fine for a few more months.. it is a tiny battery but its a tiny single cylinder motor to spin up.

so id voltage test the battery anyway to test if its weak or been cooked by the rectifier (a common honda problem) or stator.

Which year of bike??and what tyoe of battery is in it?ie a leadacid version or one of the many type of lithium?
Just to note for you or some other people...

older bikes dont get on with modern lithium batteries, as their charging units are not designed for them, requiring higher but shorter recharging characteristics to leados.

Lithium batteries are completely goosed and not recoverable if drops near and defo below 9volts, lead acids can go below 6vts and still  recover marvels of old technology.

 

Triumph regularly throw out bikes to this day that are too close to fine line electricity.. just about works if everything is brand new but add in wear, age, corrosion, natural degradation of batteries, gaining resistance of wires and parts they struggle.

Edited August 29, 2023 by RideWithStyles

[johng]

I would say it cuts out particularly at high revs . And then completely loses everything . Then when trying to start complete silence, the only thing happening is the engine management light , and the neutral light however when you hit the electric start the neutral light dies , and fades back in when not pressed. 

[johng]

@RideWithStyles no it does not make any sound when the key is turned . The battery on it at the moment is a vertex . The year of the bike is 2011 I believe. 

Edited August 29, 2023 by johng
Posted same reply by error

[RideWithStyles]

Same year as wifes bike. 
 

really doubt the battery.

the cut out is not battery directly too, So the bike is ready to start but something is stopping it.... go back to start and basics of most likley.
the side stand switch its vague and crude type and wires isn't great on these sticks with age, chain lube, road gunk etc and if the bike "thinks" its side stand it down due to the switch it wont prime or start, but the lights will still do what they normally do. Put on centre stand and give the side stand switch and wires a clean.

Sometimes it will start and go even if the side stand is fairly pushed out yet it can stop it if its not fully kicked up or the switch is out of place. 

Clean up the connection.

check that the bolts are tightened up for the side stand/switch cos its its vibration from the motor has loosen it the bike will think its stand is not correct.

that is the basics of to check first.

 

Nust a silly question, it doesn't have a immobiliser fitted does it? It if does id  pointing a finger at that if the above doesnt work.

Edited August 29, 2023 by RideWithStyles

[johng]

Ok so update , the bike shop called and said they think they may have cracked it .  They said back light is shorting and causing the battery to cut out . I’m hoping that is what it was all along ! But il find out for sure when I collect it . I will also go over all the details you’ve all sent me just incase . But hoping this could be it ! 

[RideWithStyles]

Good hope so! Id loved to be surprised.
 but not sure as the fuse should have popped if it was enough to properly short or affect the battery Or kill the  bbikes drive and fail to start afterwards . The rear light only has a a few volts and amps sending to it so to kill a bike dead...hmmm. Has someome put 30+ amp fuses in the lights parts?? Lol.
id have thought ithat would goose the battery from the start if it was to that extent.