Author Topic: P50 Won't start  (Read 3210 times)

paparush

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P50 Won't start
« on: July 03, 2011, 09:06:10 PM »
Hello All,
I've read several dozen posts on this great forum, but have yet to get my P50 to start.

The scooter sat for about a year.  Yesterday, I drained all the old gas, opened the drain screw on the bottom of the carb and drained the old gas out of the bowl.  Fresh gas w/ several ounces of Sea Foam for good measure. Old plug was very black and gunky. New plug, correct gap.  New battery, fully charged by the shop I bought it from.  Would turn over but never start.  Definitely getting gas into the carb because if I open the drain screw back open, gas drains out.  

If I pull the plug and spray some Igniter into the chamber, reseat the plug, it will start and run for a few seconds, just burning off the starting fluid.  I can do this with both the kickstarter and the electric start.

I removed the carb.  Pulled and cleaned the jets.  One question, with the small, secondary jet, should it be clear all the way through, lengthwise?  The 4 tiny holes in the needle body were all clear.  When I pulled the larger, main jet, I could see daylight through the length of the tube. Not so with the smaller jet, but I've never done this step before and don't know if it should be clear all the way through.

Having pulled the plug, spray in starter fluid, crank it, runs for a few secs, cuts off.  I've done this maybe 20 times, and the plug looks as clean as when I bought it, like it's not burning any fuel/oil mix.  

What mechanism delivers the fuel to the chamber and how do I check it?  What else should I try?

Many thanks!
« Last Edit: July 03, 2011, 09:09:14 PM by paparush »

sidthesloth

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Re: P50 Won't start
« Reply #1 on: July 04, 2011, 01:22:32 AM »
G'day mate, sounds like you have done good so far. With the cranking over, is the spark plug getting wet with fuel? I am pretty sure the pilot jet is supposed to be clear right the way through, I think that is your problem. If you can't get it clear you might be ebla to find a replacement at your local bike shop. have you tried starting it with the throttle partially open? One other thing, with sitting so long I wonder if the oil seals might have dried out and not be sealing properly.
ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

paparush

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Re: P50 Won't start
« Reply #2 on: July 04, 2011, 01:19:17 PM »
Hi Sid,
Thank you for the reply.  The plug is staying dry.  I may try boring the pilot jet through with a fine needle, just to see if I can clear it.

sidthesloth

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Re: P50 Won't start
« Reply #3 on: July 04, 2011, 03:12:49 PM »
If you can, try soaking it in some carb cleaner for a couple of hours. If you use a small drill, try to use one the same size or a bit smaller than the jet opening.
ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

paparush

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Re: P50 Won't start
« Reply #4 on: July 04, 2011, 05:55:39 PM »
Had to use a sewing needle as I didn't have a bit small enough and all the stores are closed today for the holiday.

Did manage to get the needle jet cleared and the carb reassembled.  Actually got the bike to run for a minute or two using a few drops of gas in the chamber, reseating the plug, and kicking it over.  Was able to get the engine warmed up for a while.

Trying to figure out the default settings for the air screw (closer to the front of the bike, angled upward slightly) and the throttle stop screw.

The Service manual has this:
Air Screw Opening:
BA10AB.AC.50: 1º ± ! turns

Is that one degree of opening?

Do you have any experience/recommendations for those settings?

Thanks!

Jiffycake

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Re: P50 Won't start
« Reply #5 on: July 04, 2011, 08:17:57 PM »
If this is a 4 stroke, it is 2 +- 1/2 turns.

Start out at 2 turns out and adjust as needed from there.
Agility 125 Part out and Complete A50 Motor w/ super low miles.
http://www.kymcoforum.com/index.php?topic=4718.0

paparush

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Re: P50 Won't start
« Reply #6 on: July 09, 2011, 07:31:30 PM »
Update
First, thanks to you guys for taking the time to help me.

As of 3:00pm today, the 50 will start on the first kick.
(there was much rejoicing)

But..
(you knew there'd be a but)

It runs absolutely balls open, full throttle, like the throttle is stuck all the way open.  Twisting the throttle on the handlebar does nothing and it will sit there and run at 10,000RPM (up on the stand) until I kill the switch or turn the key off.

This is with both screws on the carb set at 2 turns out.

With the seat out, I can look down and see the throttle body opening and closing as I twist the throttle.

Any idea what I've done or not done that's got this bike revving so high?

Thanks for helping this noob.

sidthesloth

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Re: P50 Won't start
« Reply #7 on: July 09, 2011, 08:42:19 PM »
Sounds like the throttle slide is in backwards, but you say you can see it open and close. If it is in backwards it will stay open most of the way.
ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

paparush

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Re: P50 Won't start
« Reply #8 on: July 09, 2011, 09:01:02 PM »
**Warning**
Noob questions ahead..

Is the throttle slide the part that screws into the top of the carb?  Spring, metal sleeve, needle?  The sleeve has a groove so that it will only insert one way, right?

With the airbox off, I can look into the carb intake and see the needle portion of the throttle valve extending into the intake (actually touching the bottom of the intake).  Should that needle move as I twist the throttle?

Thanks Sid!

paparush

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Re: P50 Won't start
« Reply #9 on: July 09, 2011, 09:03:09 PM »
Aww crap.  Looking over the diagrams in the service manual, looks like maybe the cable isn't attached to valve (sleeve). Page 11-4 in the carb section.

Going out to take a look.

sidthesloth

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Re: P50 Won't start
« Reply #10 on: July 09, 2011, 09:08:35 PM »
Yep, one side of the throttle slide has a groove to locate it in the throttle body, the other side has a sort of recess for the idle speed screw, if you turn it around, the groove will sit on the idle speed screw and not allow the slide to slide down into the carb. When put in properly, the throttle slide should sit in the carb with just a small gap at the bottom. Good to see it is a simple fix, and cost nothing too. :)
ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

paparush

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Re: P50 Won't start
« Reply #11 on: July 09, 2011, 09:40:20 PM »
When aligned properly, does it sit virtually flush with opening in the carb?

The cable is attached correctly to the valve (sleeve) and when it's removed from the carb body, twisting the throttle definitely engages and moves the valve.  Listening carefully, I'm pretty sure I can here the valve sliding up and down when it's screwed into the carb. 

From the manual - "Install the throttle valve by aligning the groove in the throttle valve with the throttle stop screw."

Gonna go check again.  Might have to take the laptop out there with me (recipe for disaster).

Thanks Sid.

paparush

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Re: P50 Won't start
« Reply #12 on: July 09, 2011, 10:03:24 PM »
UPDATE!

Sid, you're a f***ing genius (and I mean that in a good way!)

That throttle valve WILL go in two different ways.  I had it in the wrong way.  Got it properly aligned like the photo in the manual (hey, dumbass, there's a PHOTO in the MANUAL)

Anyway, thanks man.

I'm sure I'll be  back when I decide to de-restric this puppy.  Hell, now I don't want to sell it.

Code, I can fix.  Computer hardware, heck yeah.  Engines:  this is the first thing I've ever got running from zero.

sidthesloth

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Re: P50 Won't start
« Reply #13 on: July 09, 2011, 10:07:13 PM »
Excellent, these little scoots can be a lot of fun to play around with.
ZX50, 47mm cyl. kit, TZR50 CDI. Michelin Pilot Sport tyres,
Next performance mod; pumping the tyres up.

paparush

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Re: P50 Won't start
« Reply #14 on: July 09, 2011, 11:23:54 PM »
Just rode it around for 30 mins or so.  Took it to the car wash and hosed it off properly.  Lotso fun!

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