Bike cut while riding and now will not start!

[Techno]

Hi all

I'm in need of a bit of help please. I'm a long standing motorcyclist mainly large sports bikes, experienced mechanic but have never worked on a scooter of any kind, as with most bikes each model has common issues I'm hoping this is one of them. I've searched through the forum but found nothing, so I'm hoping you guys can help us. To compound matters the bike is 100 odd miles away from me, so the diagnostics is via phone and web cam, from someone who has very limited mechanical experience.

The issue, my son's PCX125, 2011 model, cut out while he was riding over to me yesterday and now will not start.

The bike's making a slight rattling noise when the starter is pushed, the engine is turning but it will not start, the noise appears to be coming from the front variator. The belt is fine, the rear wheel turns, battery is good, fuel in the tank, there's a spark at the plug, oil in the engine it's low but there, no warning lights came on or are on, bike done almost 11000 miles, the bike's never missed a beat ironically he was coming over to me for the weekend so I could service (14k) it for him!

Thanking you in advance.

[homie]

Kill switch, side stand switch, starter and stater... all eliminated. Whats next? I would think since its cranking and not starting there would be clatter in the variator and that noise would end with centrifugal force when it starts so don't focus on that too much. Must go to the next thing keeping it from firing up... fuel blocked? compression?

[Mel46]

When did he last put gas in it? Could he have gotten some bad gas?

[PCX150Rider]

As long as the battery is charged up Okay and the terminals are clean and it does respond to the starter switch with enthusiasm but with no results in starting then I'd rule out a battery problem. As you stated the battery seems good. Also spark getting to the plug eh? Which leaves fuel or air. Fuel pump? Contaminated fuel or line blockage? That's a tough one. . ..

[easyrider]

Spray some starter fluid into the air box,start cranking..Report back results.

[homie]

EZ is on to it...

A compression gauge if you have it can eliminate all the major possibilities in minutes, rings, valves, timing chain. Get the expensive repairs off the table. Would make me feel better right off.

[DAB]

Does the plug get wet with fuel, any oil on the plug?

[alx123]

Ignition, check. Battery, check. That leaves us the fuel. Check fuel lines, or try bleeding or cleaning the carb. See if fuel is reaching the combustion chamber. Also clean air filter.

[Gil]

Here are my Ideas, is there too much oil in the crankcase? I bought my scoot with a rattling noise from the crankcase also and it turned out to be the timing belt tensioner that broke because of too much oil in the crankcase. The belt tensioner isn't hard to remover to inspect.


Gil

[Gil]

Here is the noise for a bad cam chain tensioner.
https://youtu.be/YiBHpAUF5A0

[Techno]

Hi guys thanks for all the replies sorry it's taken so long to respond but I haven't had any notification to my email to say I've had replies?

Kill switch, side stand switch, starter and stater... all eliminated. Whats next? I would think since its cranking and not starting there would be clatter in the variator and that noise would end with centrifugal force when it starts so don't focus on that too much. Must go to the next thing keeping it from firing up... fuel blocked? compression?

Homie yep I'm leaning towards a fuelling issue, possibly the pump.

When did he last put gas in it? Could he have gotten some bad gas?

It's possible but here in the UK it's very unlikely especially from a Shell station, in all the 30 plus years I've been riding never had bad fuel.

As long as the battery is charged up Okay and the terminals are clean and it does respond to the starter switch with enthusiasm but with no results in starting then I'd rule out a battery problem. As you stated the battery seems good. Also spark getting to the plug eh? Which leaves fuel or air. Fuel pump? Contaminated fuel or line blockage? That's a tough one. . ..

PCX150Rider yep that where I'm going.

EZ is on to it...
A compression gauge if you have it can eliminate all the major possibilities in minutes, rings, valves, timing chain. Get the expensive repairs off the table. Would make me feel better right off.

Chances of a quality well maintained, low mileage, unstressed 4 stoke suffering anything you list is almost impossible without symptoms/noise/issues.

Here are my Ideas, is there too much oil in the crankcase? I bought my scoot with a rattling noise from the crankcase also and it turned out to be the timing belt tensioner that broke because of too much oil in the crankcase. The belt tensioner isn't hard to remover to inspect.
Gil

Oil is on the low side still in range but low.

Ignition, check. Battery, check. That leaves us the fuel. Check fuel lines, or try bleeding or cleaning the carb. See if fuel is reaching the combustion chamber. Also clean air filter.

The bike has single point fuel inject through a throttle body, there is no crab/float bowl.

Here is the noise for a bad cam chain tensioner.
https://youtu.be/YiBHpAUF5A0

To get this noise the engine has to be running!

I'm going up the fuel supply route, hopefully I'll be able to get over to him this weekend and look for myself.

[eggman]

if it was me (im half idiot) id spray some starter fluid a very small amount inairfilter box and see if it starts and runs for a few seconds

[E. Foster Salsbury]

Hi guys thanks for all the replies sorry it's taken so long to respond but I haven't had any notification to my email to say I've had replies?

Look in your Junk folder.

[you you]

I'm old school. Always start with checking for a spark at the plug first and go from there...

[PCX150Rider]

I'm old school. Always start with checking for a spark at the plug first and go from there...

Yup. . .you hit the nail on the head!

[Techno]

Hi guys thanks for all the replies sorry it's taken so long to respond but I haven't had any notification to my email to say I've had replies?

Look in your Junk folder.

Yes, done that there's nothing in there.

[Techno]

I'm old school. Always start with checking for a spark at the plug first and go from there...

Yup. . .you hit the nail on the head!

Yep did that and said so in the fist post.

[easyrider]

Did u fix it yet ?? Still working on it.. What did you do so far ??

[Techno]

Did u fix it yet ?? Still working on it.. What did you do so far ??

Hi no not yet, as I said the bike is at my son's he's 100 odd miles away. I've not as yet had a chance to get over there plus he's got very limited tools/experience, I can't drag all my tools over there just too many plus with a problem like this it's hard to know what you'd actually need.

via web cam I've ruled out, lack of spark/fuel etc. I got him to check there's fuel getting to the throttle body so the pump is working, ruled out blocked tank breather, it's a proper mystery. That said he's got very limited experience and there's only so much you can do via a web cam so it's possible he's missed something.

I'm trying to find a way to collect the bike and get it over to me, but it's a case of when I'm available he's not and or the van isn't!

[E. Foster Salsbury]

Sounds like the last thing to check for is compression. Pull out spark plug, put finger over hole and turn it over.
If he was running down the road with no symptoms and it shut off I would guess value timing. Cam chain or tensioner, cam sensor or sprocket, crank sensor or sprocket. Basic compression test should rule out all but the sensors.