The Honda PCX / Forza / ADV150 / SH Forums

Sorry for the wall of text. I wanted to provide as much detail as possible.

So a couple of weeks ago I noticed that when I started the bike the exhaust made a different sound. More of a slow "dud...dud...dud" before getting faster and sounding normal. Then a few days after I noticed this it did the same except it stalled whilst idling. I tried it a second time and opened the throttle immediately after pressing the ignition and it didn't stall this time.

A couple weeks go by and not really had an issues. Then the same thing with the slow "dud...dud...dud" sound. I'm riding home from work and stop at a traffic light. Light is on red for ages and the idle stop is engaged so this engine is turned off. I open the throttle expecting it to start up and nothing. The electronic displays on the dash go blank and then the speedo needle goes from 0 to max (like it does when you first put the key in an turn it). Still doesn't start. Close the throttle and open again, does the same with the needle but doesn't start. It keeps doing this. I turn off the ignition, leave it for a few seconds, turn on the ignition and try again. Half starts, then stalls, then screen goes blank, speedo needle up to max then actually starts and I'm able to get home.

I read the owners manual and it mentions idle stop leaves the lights on, which drains the battery and can cause issues. We're at the end of a long winter here so I'm thinking it might be the battery. I disconnect the battery and leave it on charge for 24 hours with my Optimate 4. All the test lights on the charger indicate the battery is in very good condition. I put the battery back in the bike and start it. Whilst it doesn't do the slow "dud...dud...dud" it doesn't seem to start strongly. I turn off the idle stop as mentioned in the owners manual and ride the bike like this for the next couple of days. The more time goes by the better the bike seems to start. After a few days I turn the idle stop feature back on. For the first day the bike seems to run perfectly. The next day it doesn't seem to start as strongly. The third day it seems a bit worse. Fourth day it stalls again at a traffic light. Since then I've ridden with the idle stop turned off.

Any ideas? Could the idle stop be affecting/preventing the battery from charging? Is the battery a total red herring?


A few observations that may be irrelevant.

1) When it stalls the bike has been on a slight incline. London is mostly flat but it's stalled on roads that are slightly uphill. This might just be coincidence.

2) The bike has done just over 5k miles and was bought from new just under 2 years ago. The spark plug hasn't been replaced yet.

3) I just changed the engine oil (after these issues started) and the bike seemed to run a little smoother.

4) The air filter looks okay.

5) It is technically still under warranty (just) but I only got the first service (it was free). I missed the second (my local dealership closed down) and it is due the third service around now (5k miles). I don't know if missing the second service voids the warranty in the UK.

One of the reasons the new 2014 PCX has an unrated battery. I doubt I will be using this feature in the main - at least in normal traffic.

Switch the start stop off for a while and see what it does. It's not unknown for battery problems so it might be just that.

What do you mean by start stop? If you mean the idle stop switch, as mentioned I tried turning that off. Problem only went away temporarily.

It sounds like the stop idle is draining the battery too much. There is a large draw on the battery every time the bike is started, so if it is weak from too many starts without enough time to recharge you will have problems. It could be that the battery has a weak cell or else you do a lot more stop than go in stop and go traffic. Turn off the idle stop until you can afford a new battery. You should be able to get a lot more miles per smiles that way before the battery finally does get too weak to use.

I'm having a similar issue now. The bike is at the dealer and I have no new updates though. Do you have a 125 or 150?

Mgalutia88, I have a 125. Please post back if you find out what's wrong with yours.

I spoke to a dealer on the phone and he said the warranty is valid if the service was carried out by a competent mechanic i.e. I don't have to have stamps in my service book. If this is true and charging the battery doesn't fix the issue I will try to exercise my warranty.

I just changed the spark plug this morning. The old plug looked perfect according to NGK (http://www.ngksparkplugs.com/tech_suppo ... p?mode=nml) but we'll see if the new plug makes any difference.

My dealer has no problem wih me doing my own maintenance and hasn't asked for my records of when and what I've changed and serviced.

What country are you in?

Hi I am going thro a very similar starting problem. Sometimes she starts right away. Other times the "dud, dud, dud," start. Sometimes it just doesn't start. But when I move the bike a bit ( change piston position) it starts. Mine too is about 2 years old. 4000k on the clock. Has only done its 1000k service and is due for 4000k service. The 4000k service does not include spark plug change, only view. I
am not using my idle stop. I have ruled out the battery after getting it tested in a battery shop. It's as good as new was the shop keepers verdict. Could be spark plug, or valve clearance or electronics problem. The dealer mechanic is unable or unwilling to diagnose over the phone. I'm afraid it will cost me an arm and a leg. Hence trying to compare notes with people with like experience. Trust this helps.

The first thing I would do if you have access to a voltmeter is check the voltage at the battery during starting, eg when the starter button is pressed. The battery might be fine sometimes but breaks down under load. If the voltage drops below 10 volts it's maybe on its way out.

I'll check what mine goes to and let you know.

Just checked mine. It has lain for 2 days. The battery voltage was 12.6 volts ignition off, 11.96 ignition on, lights on etc, and dropped to 10.7 volts when starting.

How did the guy check you battery. Just check the voltage or use a load tester or a capacitance check.

I use a capacitance tester at my work but sometimes they read ok but break down when loaded up.

I'm in the US in Missouri.

To address the battery point, at least for my scoot, it turns over normally. It started with not wanting to start one day, then went to starting to die out when I got over 45, then just felt like it cut fuel AT 47-48mph. Everything else is normal.

Mgalutia88 wrote:I'm in the US in Missouri.
To address the battery point, at least for my scoot, it turns over normally. It started with not wanting to start one day, then went to starting to die out when I got over 45, then just felt like it cut fuel AT 47-48mph. Everything else is normal.

I seem to recall someone having their ECU reset to sort cutting out over a certain speed.

Yes, that's correct iceman. I have suggested that to the mechanic at my dealer but I haven't spoken with them since Friday and there are no updates yet. They will be open again tomorrow. I'm involved in fixing my Porsche 944 at the moment and readying it for the first autocross of the season two weekends from now. I have a transmission to swap - 3hrs - and currently am replacing my oil cooler seals. It just needs to go back together.

I accidentally left my keys in for an hour and it drained my battery completely and needed a friend's car battery to help jump mine. That's been the only time the battery has failed on me in the two years I've had mine (plus the two years that my friend had it).

Just moved to the 2014 model this week, has a bigger battery, LED to reduce power consumption by 60% and will auto disable the idling-stop feature when the battery is low.

I was worried the 12v charger would suck all my battery life, but it only works when the key is full engaged (headlamps come on).

Are you not supposed to jump with car battery?

logepoge1 wrote:Are you not supposed to jump with car battery?

You can as long as the car is NOT running.

Oh yeah that's right. It's the alternator that could fry it due to high current