weird electrical problem

[budd]

first this issue isn't afflicting a Storm but it is an Honda, a 125cc Honda Dylan to be exact, a friend of mine owns the said scooter and it is not behaving is itself. It won't start on the key tuen the key and i makes a slight buzzing noise but won't turn over, it appears the battery is totally flat but when you put the meter on it it's showing 12+ volt but when you turn on the ignition the voltage drops to 5-6 volts, turn off the ignition and it jumps back up to 12+ V, something is taking 6V when the ignition is switched on ??? what could it be? solenoid ? anyone any ideas ?

[TheGingerBeardMan]

Buzzing or a click is usually the sound of a sticky relay or solenoid.

It's also the sound of a flat battery - giving just enough to pass a minor current through said relay.

Regulator may be goosed? Starter motor brushes may be worn down too far. Is it points or CDI? A bike with sticky points will also "click" or "dirl" (a fast "ticka-ticka-ticka"...then nothing)

The battery getting drained on ignition/key turn could be a bad connection, or a bad earth going to the frame. (check battery earth and clean up frame connection)

As with a lot of batteries that appear flat...they will "recover" a bit and the amps will creep up. But, as you say, as soon as you ask it to provide power, it instantly drops again.


Check the HT spark plug lead and the coils black earthing wire that attaches to the top tube on the frame, or onto the headstock.

Are the wires standard and not bullet connectors or botched and taped? If they are "modified", there may be a loose connection somewhere near the ignition.

Have a look to see no wires are routed wrong, and are getting trapped, stretched or pulled when turning the bars.

Is it blowing fuses? (If so, again, that would point to a loose connection or bad earth cable connection point....)

A process of elimination I'm afraid without hearing it, and determining where the buzzing is coming from (Front lower, middle left, or under seat/side panel etc)

[budd]

thanks for the reply, battery is only a couple of months old and is showing full charge,CDI no points, wiring is stock and not modified in any way, the way the voltage drops when the ignition is switched on as got me thinking solenoid but as you say it could be a bad earth, or starter relay

[TheGingerBeardMan]

OK. Battery is new (short of having a duff new battery), but we'll assume that's ok.

If the voltage drops when turning the key, the bike is drawing power from somewhere (as in, the power from the battery is escaping before it gets to the intended place.)

So, this points to a bad / corroded Earth point.

If it was a sticky relay, the power wouldn't drop like that. It would stay 12 volts, and maybe only drop about 1 or 2 points (down to 10 amps tops)

Check black earthing cable from battery to frame. Remove, see that the inside is not all green with corrosion. If it is, then you'll have to cut it back to a clean copper colour (which is shortening the cable), but it can be re-mounted to another part of the frame.

If the cable is fine, clean up the paint around the connection/frame bolt back to metal, and sandpaper/emery-paper the large hoop connector.

Same as the ignition coil and starter motor. See that no corrosion is present, and clean up all connections.

See if you can hear where the buzzing is coming from when the button is pushed!

You can try turning the starter motor direct from the battery. If it spins/turns, then the brushes are fine.

Take the spark plug out when testing every-time you go to push the starter, as this make it easier on the motor (no deep compression to try and push).

If you have access to a manual, it may tell you which way to bypass the relay or solenoid. Worst comes to the worst, a replacement for a 125 shouldn't be more than 10-15 quid.

I shudder to think what a CDI would be - anything from £25 quid up to silly money?


Once the bike is successfully spinning on the starter, or relays are opening etc (fingers crossed), then test for a spark. (put spark plug into plug cap, and place plug against the frame - DO NOT HOLD THE PLUG, as you will get a big shock. Push the button, and you will be able to see the plug spark colour.

But this is all depending whether the earths are all good, nothing in the loom is loose or "adapted".

Check that the wires from the ignition barrel are tight into their connections, and also tight into the relevant parts of the loom (maybe all stuffed behind the headlight?)

Not heard of a Honda Dylan I'm afraid. But will now go and google it to see if it's a moped (like a Honda melody) or an open bike, like a CG125

Best of luck.

[budd]

cheers mate all great suggestions it's a scooter not a proper MC I'll go through the wiring and check for damage / bad earths etc, BTW it will start if I put may booster pack on it but I'm a bit reluctant to use the booster for fear of putting to much current through the system, anyway it looks like I've got the job of sorting it out tomorrow I suppose it will keep me out of trouble checking wires !! I've also got a VFR 800 with braking issues to deal with, it's randomly locking the rear brake after the application of the front brake !!! bloody linked braking system is a proper pain, I'm guessing the supplementary master cylinder which applies one of the 3 rear caliper pistons is sticking and not allow the applied pressure to release another PITA job no doubt

[TheGingerBeardMan]

Yup, motorbike wiring is a right PITA. Luckily, I have someone with a lot more patience than me to faff around with stuff should I need it done.

As for the VFR, Dunno if it's a generation 5 or 6, but here is a link (below) to bleeding the systems - Taken from VFRWorld Forum.

Have a read down the posts on that page, and it may help or point in the right direction.

With a linked system on such a new bike, it's doubtful that one of the pistons will be sticking. It's more likely to be the complicated air system.

VFR linked brake bleeding major problem: help please

[Cadbury64]

cheers mate all great suggestions it's a scooter not a proper MC I'll go through the wiring and check for damage / bad earths etc, BTW it will start if I put may booster pack on it but I'm a bit reluctant to use the booster for fear of putting to much current through the system, anyway it looks like I've got the job of sorting it out tomorrow I suppose it will keep me out of trouble checking wires !! I've also got a VFR 800 with braking issues to deal with, it's locking the rear brake after the application of the front brake !!! blooding linked braking system is a proper pain, I'm guessing the supplementary master cylinder which applies one of the 3 rear caliper pistons is sticking and not allow the applied pressure to release another PITA job no doubt

Yes pretty sure that will be a SMC problem on the VFR. May just have a little piece of crud in the return bleed hole, so try a clean-out first.

[budd]

the VFR is a Y reg '00 so not the latest, to be honest the system appears pretty simple, well is principle at least the n/s front brake caliper pivots when the brakes are applied and pushes a plunger on the SMC which in turn applies a little bit of back brake, nice and simple (in theory) unfortunately it's all the pipes and valves in between that add the complexity, bike brakes can be difficult enough to bleed without extra pipes going here and there,there's something else called a PVC under the seat that apparently can cause problems, although I'm hoping it's just the SMC that needs a bit of a clean/free off.

[popkat]

Sorry if already posted, not read whole thread.
You need to pull in the brake lever to start the scooter, either one should work, the brake light switch also completes the iginition/start circuit, if these are sticking then the scooter won't start, simply on a scooter if it doesn't start when brake pulled in your brake light doesn't work either, they do stick often so worth checking.
Also most scooters break the starter circuit if the side stand is down, start it on the centre stand.

Other than that is sounds like the starter solenoid, if this is stuck it will draw power from the battery but not pass it on.


.

[budd]

Sorry if already posted, not read whole thread.
You need to pull in the brake lever to start the scooter, either one should work, the brake light switch also completes the iginition/start circuit, if these are sticking then the scooter won't start, simply on a scooter if it doesn't start when brake pulled in your brake light doesn't work either, they do stick often so worth checking.
Also most scooters break the starter circuit if the side stand is down, start it on the centre stand.

Other than that is sounds like the starter solenoid, if this is stuck it will draw power from the battery but not pass it on.


.

not getting a ignition light it appears dead, but the battery is fully charged, however there's an audible buzzing from a relay which disappears when either lever is pulled I'm assuming is causing the problems, as you say scooters don't start if the brakes aren't on this relay is definitely linked to the brake levers and possibly as you say the brake light, fortunately there are quite a few ebayers currently breaking these so I shouldn't have much trouble getting hold of replacement relays

[Pete.L]

If it will start from your booster pack I'm inclined to think your battery is toast, even if it is fairly new.
If there was a short somewhere a fuse would go. Could also be a bad terminal on the battery. I would also be inclined to check the regulator to see if your battery is being charged properly.

Pete.l

[budd]

well I'm properly stumped with this, despite changing the solenoid, starter relay, CDI, regulator and even the starter switch it is still doing the same thing, ie not starting with a OE battery, the starter relay is buzzing when the ignition is turned on (this buzzing stops if you pull a brake lever), while the battery is new and showing full charge I except it may be dodgy so I've tried a new battery but again to no avail, what's properly pi%%ing me off is it will start no problem from either a booster pack or from a van battery but not from a M/C battery, something is taking the power from the battery but what? what's left to check ? ignition switch ? the wiring looks fine so what could draw 6 or so volts from the OE battery to stop it working? it's not as if it's struggling to start without a more substantial power source is simply won't do anything except buzz the starter relay, no ignition lights nothing not even the digital clock !! I'm getting to the end of my tether with this thing

[TheGingerBeardMan]

Blimey - Sounds like you've done everything but pull it apart completely. Hmmm Erm...I take it you are using the correct size battery? A 12v 6ah battery and not using a 6volt 12amp! ?

It's strange it does start with a van battery, but mind you, a transit battery is about 50 to 75 amps depending on what you buy.

Pull all the wiring apart (as in disconnect all lights, horn etc), as that will act as a "roadway" for the rogue current to drain into. Have as little as possible plugged in apart from the starter motor or essential plugs to the CDI - coil etc, and again, lessen the "tracks" where power can run away into. Fuses too, if you pull the ones not required from the box.

Once each individual thing is removed, then you will know what works, and what doesn't.

The last thing you really want to do with a van battery, is keep powering too many amps through the system. It may damage the CDI or reggie rector-frier.

What happens if you disconnect the brake / starter assembly, so you don't have to pull the lever to start it? Can you by pass that and start it by "shorting" the starter motor across, and using the OE bike battery?

It sounds like you've done everything you can do, so, I'm kinda stumped by this. Not ever having had a bike that starts with pulling in a brake, I'm a bit out of my depth with further suggestions for it. Short of literally pulling it ALL to bits (loom wise, and testing every single wire for continuity)

Hopefully, popkat can come back in, as he was a lot more knowledgeable about the Honda Dylan!

The problem WILL be found, but it may take a lot of head scratching and coffee, and swearing, and spanner throwing to find it. Stick at it. Then, walk away and calm down. Then give it another look with a fresher head.

Failing all that: drop it off at the nearest canal, and say some bugger nicked it.

[popkat]

the correct battery is a YTX7L-BS In case you have the wrong one.

[roger64]

It sounds like the starter motors sticking, strip and clean starter motor or first tap the starter with hammer when trying to start it
Or put 12v directly to the starter with the other battery if it spins then its not faulty. Reduce from possible faults.