Won't start - stalls at low speed / while idling

[mattpwyman]

Hi all, my pcx has developed a fault where it is very difficult to start and when I do get it started it will only run at high revs, if it slows down or idles it will cut out.

I've done a full service, changed the spark plug, oil, belt and rollers and I thought this would solve the problem but it's now got worse and I can't ride it.

Could the problem be the spark plug cap or the ignition coil?

[springer1]

Maybe bad fuel or dirty fuel injector. Before I'd trouble shoot anything else mechanical, I'd drain the fuel and add fresh with a splash of fuel injector cleaner.

Some people think injectors can't get clogged because they are under pressure from the fuel pump. But what happens is that a thin coat of "varnish" or whatever you want to call it changes the injector's output from a "spray mist" to a "squirt" which isn't as combustable.

http://www.fuelinjectorcleanerhq.com/lu ... treatment/

I don't know that your problem is mechanical or simply fuel or a clogged injector, but this stuff really does work.

[fish]

Miles on the engine?
Valves ever checked?
Do you use a Top Tier fuel ? - all of which have cleaners in the blend.
Oil, belt, rollers won't solve hard start issues.
Fish

[mattpwyman]

Thanks for the reply's chaps I'll get some injector cleaner and give it. Fish - she's done 55000 miles and no the valves have never been checked so if the injection cleaner doesn't do the trick I'll check them next.

Matt.

[easyrider]

First I would check and make sure fuel is fresh (no water). Are you getting any check engine Lights ?? Have you done any work on the engine?Listen for any hissing (vacuum leaks/ line broke).Air filter is not restricted correct ?? Idle is controlled by several sensors but usually the IAC valve is first suspect.Clean and check that its working properly.I think you should hear it activate once key is turned on, but still can be dirty, or not moving..

[pcx man]

I had this problem and it was valve adjustment. It acted the same, very difficult to start and when I did get it to started it will only run at high revs.

[springer1]

55,000 Miles and no valve adjustment ? .... did you mean 5,500 ?

[you you]

Thanks for the reply's chaps I'll get some injector cleaner and give it. Fish - she's done 55000 miles and no the valves have never been checked so if the injection cleaner doesn't do the trick I'll check them next.

Matt.

Erm..Even I would check the valves after 55,000 miles. Has the oil been changed?

Ever?

[PCX150Rider]

You say it's had a "Full Service". But no valve check or adjustment? That's not a "Full Service".

Since it's either fuel, spark, or air. I'm thinking it's a fuel related problem since it seems to have happened rather abruptly. Either contaminated or starving for it.

Your PCX is indeed in need of a valve check and adjustment if required.

On another note it could be a bad plug. . .cracked porcelain perhaps? But I'm leaning towards fuel issues.

This video is for a lawn mower spark plug but a lot of the same principles apply.

Just my 2 cents.

[Nemesis]

@mattpwyman

Can you make a video? Does the engine runs smooth on slightly higher revs on only on high revs?

[you you]

You say it's had a "Full Service". But no valve check or adjustment? That's not a "Full Service".

Since it's either fuel, spark, or air. I'm thinking it's a fuel related problem since it seems to have happened rather abruptly. Either contaminated or starving for it.

Your PCX is indeed in need of a valve check and adjustment if required.

On another note it could be a bad plug. . .cracked porcelain perhaps? But I'm leaning towards fuel issues.

This video is for a lawn mower spark plug but a lot of the same principles apply.

Just my 2 cents.

X2

[popeye]

I have had this problem with my PCX 125, Honda tech is now saying it's a fuel injection fault as the diagnostics is highlighting it. Had it in for it's 4500 mile service just a couple of weeks ago and pointed out this problem which was getting worse with every journey. At the time they said they had plugged it in and found no faults but found some water in the air filter and clearly dismissed it as that. After charging me an exorbitant £512 for parts and service gave it me back and the issue continued. They now have it back and have just contacted me to declare the injection issue.

[d1ckyh]

I vote for valve adjustment. Had a gy6 clone with same issues and adjusting the valves took care of it

[fish]

Once again, seems nobody wants to include a valve check when full servicing a scooter (or motorcycle ).
55,000 miles and no valve service .....his symptoms match textbook on what to expect from out of whack valves.
Could throw more pasta at wall....or adjust valves, then have coffee and a donut.
Fish

[Oyabun]

+1 to Fish's valve check comment. I'd check that first.

[you you]

Once again, seems nobody wants to include a valve check when full servicing a scooter (or motorcycle ).
55,000 miles and no valve service .....his symptoms match textbook on what to expect from out of whack valves.
Could throw more pasta at wall....or adjust valves, then have coffee and a donut.
Fish

What type of pasta?

[springer1]

From the standpoint to financials, if I had 55k miles on a scoot that started acting up I'd buy a new scoot instead of throwing time & money at the old one.

I understand the emotional ties but Sorry, I have a MC that's about 50 yrs old but I don't rely on it.

[WhiteNoise]

Once again, seems nobody wants to include a valve check when full servicing a scooter (or motorcycle ).
55,000 miles and no valve service .....his symptoms match textbook on what to expect from out of whack valves.
Could throw more pasta at wall....or adjust valves, then have coffee and a donut.
Fish

What type of pasta?

Duh, the kind that sticks you silly

Flashback!!
Back in high school or was it junior high school's cafeteria
they served jello several x/a/wk as dessert. Uhhh, don't know 'bout ya'll but Jello ain't my fav, especially if it's yella or worse yet...green!!
Anywho, the cafeteria was really big. Thinking back it kinda reminded me of a prison's cafeteria ya see on TV. WAIT! It Was in high school!!
Ok so our group was rowdy bunch of hooligans, for us lunch was a time to "Cut Loose"... Have fun, and get away with it! Everytime the cafeteria's monitor's turned their backs we blew jello on the walls and ceiling (at each other too - crazy).
We were Naughty teens!

Did ya'll ever do this? Ever? you maybe asking how. Ohh-kay
Simples, We took our milk straws and shoved them into our jello. But! you Must create suction first by placing index finger on one end - Then push it in. Tah-Dah MAGIC!
Straw is loaded and ready to Blow anyplace you aim. Give it a hardy one and she took flight!

fish, it looked like green and yella spaghetti jiggling and dangling like streamers from the ceiling.
What fun times we had and What trouble we got in. The Dean knew us by our first names. Not a good thing.

In the end, I still graduated along with the other 700 students in my class.

[WhiteNoise]

springer1, I understand your viewpoint and will add that riders age and health can matter too.