Cheap 50cc can’t get it to run

[Farmingstock]

Gave a quid per cc for a basket case peugeot XPS 50cc well I think that’s what it is.

It’s just a bit of fun for my son the ride in the fields.

Anyway it’s got good spark, poured fuel down the plug hole seams to have good compression but it won’t start. Doesn’t even try to.

It’s only got electric start and I’ve hooked a car battery to it, still nothing, cleaned the carb, changed the plug, tried squiring brake cleaner down the inlet. Nothing?

Any ideas? Can’t find a manual anywhere on line?

[jaffa90]

Is the spark plug getting wet with fuel without helping it?
If it has good compression / suction then when is it sparking?

[Farmingstock]

The plug wasn’t wet without helping it, but it should have started with what I put in, there is a strange petcock on the tank, has electrical wires going to it but when fuel is in the tank nothing comes out!

I know that is an issue but not sure what it’s meant to do, really need to find a wiring diagram as there is no nutral light and some other issues!

[Farmingstock]

Bought and fitted a new top end, still won’t start?

There was no play in the con rod, everything seamed fine, it just won’t start.

I’m going to take a look at the wiring next, however it has a good thick blue spark, definitely getting fuel now as the plug is wet after trying to start it.

Any other suggestions?

It has the AM6 engine that’s fitted to many other bikes.

[Easy-X]

If you've definitely got spark and fuel then there's timing to look at, is the air intake blocked and similarly how's the exhaust?
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[jaffa90]

[davebike]

Just a thought as I have seen it recently
Get a puller and remove the flywheel / rotor and check the woodruff key is intact if not correctly fitted and tightened the snap and ignition timing goes out
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Dave
NC750Xdct + others at work !
davebike1@gmail.com

[Farmingstock]

Thanks for the input guys much appreciated.

I’m going to make some repairs to the loom as it’s a bit dodgy here and there, there was a good spark but it’s just peace of mind to make sure it’s fine.

Exhaust is clear and can feel pressure coming out when turning over!

Carb has been cleaned and jets are all clear!

My next port of call is taking the flywheel off and checking the woodruff, The crank is obviously spinning but it needs checking to be sure as it’s pretty much the only other possibility?

Will keep you posted but any other ideas please let me know, thanks

[Farmingstock]

Put the wiring back on, now it won’t even turn over, it’s a good hob I’m not on an hourly rate doing this!

If I put power to the starter relay (to the wire coming from the switch, the bike turns over and there is a thick blue perfect spark, but it still won’t start at all!

Should there be power to the ignition? Ie from the battery? I’ve not changed anything so not sure why it’s not turning over now! It’s so frustrating!

Still won’t start no mater what I do, there is only an electric start!

New battery
New top end rebuild
Carb cleaned all jets clear
New plug
New plug lead and cap
Fresh oil in gearbox
Still nothing at all! The bike is in bits so can’t really bump it, I’ve ordered a flywheel removal tool to check woodruff key!

[stevo123]

Mare. Only suggestions now are compression and as you say to check woodruff incase timing is out (not sure where the pick up is but could be on that side)

[Farmingstock]

Got the flywheel removal tool so will check when I’m back, there’s a thick blue spark so I’m guessing pick up should be fine, maybe a lazy starter?

Will check that next and maybe change bushes!

[Farmingstock]

Well the flywheel tool is the wrong one! Too small and not sure about the starter either, it’s not as healthy as I’d like it to be!

Looks like I’m gonna have to wait till Wednesday to continue!

[Nobby the Bastard]

The battery probably needs charging now.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Farmingstock]

Yeah, fully charged the battery again! Going to get it to a position where I can try and bump start it! That way at least I will know if it’s just the starter after all this!

[Nobby the Bastard]

Am I right I thinking its a scooter and has no clutch?
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Farmingstock]

No, it’s a trials bike look kinda like a derbi sender 5/6 gears, clutch (but I need a cable)

[Nobby the Bastard]

So no clutch cable so you can't pull the clutch in. A lot of bikes (and even some cars) won't start without the clutch pulled in.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Farmingstock]

Yeah, pulled the lever in with a pair of mole grips but still nothing, there’s no kickstand or nutral wires either which is a bit strange but there is spark so any electrical failsafe would cut spark so I’m guessing they are not needed.

I’m pretty much odds on now it’s the starter motor! We will find out tomorrow if the cables are the right ones! Fingers crossed

[Farmingstock]

Well I got it going with a bump start so must have been the starter motor all along!

However minutes after getting it started the head gasket went, it was only running for a matter of minutes if that.

After stripping the head off again the head gasket, which is an o-ring was all frayed and split.

Maybe a design fault but I will order another any suggestions on re-fitting? I used some assembly lube to fit first time but obviously wasn’t right.

I can’t find any torque settings for the head bolts either?

[slowasyoulike]

[Farmingstock]

The thought had crossed my mind on several occasions, however seeing my son jump on it and ride its up and down the yard a couple of times made it worth the while.

Few bits to order now.

[Farmingstock]

Got the bike so it was running, then the head gasket split and it wouldn’t start, tried again with a new head gasket (just a rubber o-ring) started straight away, ran perfectly ticking over for a minute or two whilst I let it get to temp, went to set off and the head gasket went again!

They are just an o-ring a bit bigger than the piston, but it keeps popping them? Is there something else I should use?

Or could there be another reason why it’s popping these head gasket o-rings?

[Nobby the Bastard]

That sounds more like a barrell base gasket, but if I remember correctly some bikes had an o-ring type gasket.

Typically a head gasket is a copper one.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Nobby the Bastard]

Okay, had a quick google and it is indeed a o-ring type.

How are you doing up the head, you shoulld tighten it in a criss cross pattern so that the head remains flush with the barrel.

I suspect that this particular gasket is very suseptable to damage if over or under torqued so are you using a torque wrench?

Edit: Is the bottom of the head flat? Put it on a perfectly flat surface like a pane of glass or a mirror and check. Distortion will mean the gasket will fail quite quickly.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Farmingstock]

This is the head and the gasket, the head sits on those rings so not completely flat as such, I cross tightened to 18nm, it’s the inside one that keeps going! I’ve checked the water pump which spins when cranking, changed the crank case oil, was no water in that! It’s a nightmare.