Please help, ET4 cut out and won't start please help

[etfour]

Hi, I have own this ET 4 1998 model 124cc two days and then this happend.

I was riding along with the mrs on the back, from home we rode out 18miles had some food and went to an isolated work car park where she had a potter around as she is practicing for her cbt.

After her riding around for 1hr we headed back on our 18mile journey, then suddenly halfway back doing around 40-50mph along an A road. "voooomm" the engine cut out and all power ceased! Kinda sounded like something internal when but am not sure yet.
I have taken off the left side crank case(kick start side) where the drive belt is, an I have seen noting snapped to my knowledge.

I tried the electric and kick start with no luck.

The spark plug has spark, the fuel seems to be entering the carb/engine and the starter motor ticks over.

I am yet to open the right side or engine head, but I shall after draining the oil.

The scooter appears to have had a new battery fitted.

I normally do my own oil changes, cam belts, brakes on cars but am not experienced with engine trouble shooting but do like to get my hands dirty and learn.

Any help much appriciated!

[henri]

to just cut out like that quite often its a electrical thing , loose wire ,bad plug, something along those lines you'll have to start simple an work through it , check connections -new plug-make sure ht cap is on right as there awkward to get too, that sort of thing .
if it stumbled to a stop that sounds more a fuelling fault , if ya get some easy start an dose it with that as spinning on starter motor if it fires an trys to run its a fuel issue ,if it wont even pop on that its electrical -no spark under load type of thing.
i take it theres still compression/resistance when kicking it over ,not just the resistance of valve springs .H

[etfour]

Thanks for advice, I have checked for a spark and there is one, I'm not 100% sure if it's big enough so will pick up a new plug tomorrow along with some quick start fluid.

Sorry to be a noob but how do I test compression and resistance?
I have turned the engine over with a socket wrench on the drive side, anti clockwise and can hear/feel pressure coming out of the exhaust and the outlet which goes into the air filter.

If it is the electrics... Is there a way for me to start the engine disconnecting wires? At east I would be able to eliminate mechanical fault?

Could the choke be stuck on?

Thanks

[henri]

if youve turned the engine over by hand or kick an can hear it sucking/blowing its moving air an has some compression ,wether its enuff you can only tell by doing myself an experience ,if its electrics stopping it, removing wires will make it worse ,as a loose/broken wire is what the problem could be . an if choke was stuck on it should start an then die when warmed up ,as the lectric chokes settle into the on position when turned off an then go to off position when scoot is started an lectrics supplied to them .if the choke stuck on it might explain scoot stopping but not it not starting when cold .
try the easy-start test, then you can narrow it down to fuel or lectrics ,as its turning by hand an there was no bang/seizing/noises when it cut out i think we can rule out major mechanical faults for now .
ive had trouble in the past with piaggio vacumn fuel taps like on the et4 , pull the thinner pipe off the carb manifold an suck on it with the other pipe to carb in a jam jar ,you should get a flow of petrol into the jam jar an none in ya mouth .if not ,ya fuel tap has failed .get a genuine piaggio replacement if thats the case as quality of the pattern parts 1's is variable to put it politely , non politely there from c**p to bl**dy c**p . H

[etfour]

I have just tried a new spark plug and no luck. I checked the plug by placing it on the engine and pressing ignition, there is a thin blue spark, is that correct?

I opened and closed the throttle intermittently whilst holding ignition on and it popped off (quite loudly) the carburettor, does this show compression? I have refitted it even tighter now.

I even tried spaying a little quick start in to the air intake with no luck. Shall I try spraying lots whilst kicking over? Do I have to open the throttle fully?

Any tips or suggestion appreciated!

[etfour]

Henri, thanks for your reply I must have been writing as you where posting.

I tried the fuel tap and all is well.

Just tried holts bradex easy start into carb whilst opening and closing throttle with finger on te ignition, no luck.

Just noticed that little needle primer thing in the carb no longer shoots out petrol when pulling throttle since me taking carb off and on yday. How do I get the pimping again?

?:-(

[etfour]

Hi world, I purchased the wrong size compression tester, new one in the post! Be here sat or Monday.

That little nipple thingy is pumping out fuel again now, I've installed some some fuel line and thought I would give it another go with easy start, what I noticed was whilst holding the ignition and continuously spaying the stuff into the intake whilst the throttle was open it made a pop and seemed to be popping out the easy start!

Does this have anything to do with my issues?

Thanks

[etfour]

Hi world,
I have managed to start the et4! With a lot of tinkering (in my amature way) the problem was the valves somehow became bent, resulting in lack of compression.

I have straightened the valves and re seated them and all seems fine so far.

I will test ride it tomorrow to ensure all is tip top. If so the next step is a full refurb.

Thanks Henri for your assistance

[henri]

you say the valves were bent ,an ya straightened em , do ya mean the valves in the head , the inlet an exhaust ,as if there bent that means the cam chain/valve timing has slipped an the piston has hit them , you need to get a manual an check the valve timing , i'm away from home at moment,family care commitments,but memory tells me theres a mark on the rotor/crank ya line up with a mark on the cases an then theres a mark on the camshaft ya have to line up with 1 on the head whilst tensioning the camchain with the tensioner on the rear of the barrel nearside ,
anyway ,if valves where bent its a engineering job to straighten them properly,otherwise they will bind in the guides an cause problems ,cheaper to replace than fix , i wouldnt ride or run the engine til youve re built it totally,or even replaced it, the cost is about even , Henri

[etfour]

Hey Henri,

Thanks for the reply I hope everything is goin well with the family care commitments! Family always comes first!

I am mechanically a noob but am quite good IMO when I get into technical things.

Unfortunately I did run the scooter before seeing your message, I ran the engine idle and with slight revving for about 15-20 mins with no issues.

Then in the evening I took it for a spin locally and everything seemed sweet, but then after about 2minutes of gentle riding a tapping/clicking noise occured and it slowly sort of died and then wouldn't restart.

I believe it's lack of compression again as I have taken the head off and I can see a gap in the intake valve but none in the exhuast.

I think the noise was the intake valve hitting the piston head? Why would this happen after I ran it for a while and not at the beggining?

Why was it initially that both valves where bent and this time only one?

Is it definatly recommend I buy 2 new valves and reseat them? Also how do I prevent them getting bent again?
I would imagine I need to torque all bolts in the engine perfect, check chain tensioner is good? And do the timing perfect? Should the timing marks always be bang spot on to a "t"?

Thanks!

[etfour]

Oh also when I reposed the engine there was a lot of black stuff on the user side of the head and valves and piston head and spark plug how is this caused?

Thanks again

[henri]

valve timing marks on a 4 stroke "interference" engine (the piston an valve heads move in same space)have to be spot on ,if 1 valve has contacted the piston again the timing must have slipped again or been re-set slightly wrong ,ya need to check the spring in tensioner an the "slippers" guides the chain runs against ,once agin youve caught me away from home n manual,was only back for 1 night an forgot to grab the "haynes book of lies", memory says 1 guide can move with head removal other/front 1 is kept in by barrel so if youve not disturbed that it should be in place,sorry from memory cant recall the "marks" better,
an the black stuff is prob carbon ,from loads of short town journeys or in a hi mileage scoot wear in engine, H