KymcoForum.com
Scooters - 50cc => Agility 50 => Topic started by: The Rookie on July 18, 2012, 09:14:28 AM
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Hi, back again, after doing over 100 trouble free miles the daughters Scoot seems to be suffering fuel starvation, will run fine for a while then suddenly loose power over a couple of hundred yards before cutting out, first few times it restarted after a lot of cranking, then last night it wouldn't - at all!
Plug comes out dry, no smell of fuel at exhaust, sucking on manifold pipe to activate the valve at tank seems to allow fuel out OK, not done much else as I was flaked after pushing it 4 miles home and not eating dinner until 9:15!
Any ideas gratefully recieved.
Yes tank is brimmed!
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Check the carb diaphragm...
(http://www.chinesescooterreference.com/manual_images/CV_Carb_Diagram.gif)
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OK thanks, was planning on getting the carb out tonight and check for fuel in the bowl, will check the diaphragm as well.
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Check the fuel filter is clean. I had issues like this before on an old car. Once it cut out and stopped crap and sedimemt in the filter would fall down and clear it again then it would restart. Once i drove a bit the filter clogged up again and it cut out again.
Also double check you didnt pinch or squeeze a fuel line somewhere when youve been working on it and that all fuel lines are tight at clamps or joins.
Also check the manifold from the carb to engine is sealed good and not been split under the clamp that holds it on causing an airleak, that makes it hard to start and it idles ereatically if you got an airleak.
Did it just stop or splutter and then stop? Like when you just run out of fuel?
Could be your choke was sticking on and flooding the engine but since you said the plug isnt smelling of fuel this doesnt sound the problem.
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According to my daughter it lost power and was stuttering over a couple of hundred yards and then cut out, fuel filter is clear (did a blow through test) and no pinches in the line, when I supply a vacuum to the control valve fuel runs from the end of the supply line to the carb.
Was going to check the manifold when I have the carb off tonight.
Choke goes off (hear the revs drop) and as you say the plug would be black and stinking (it was neither, though I swapped for a new plug last night anyway!)
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Bad plug lead? Or broken lead end? Sometimes they break or come apart where the plug end screws onto the lead wire.
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Plug lead felt fine, solo on the roadside I couldn't check for a spark but will do when I have help!
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Could also be a little dirt or crap in the carb or a blocked jet?
In fact it could be a lot of things really, time to get the tools back out and investigate.
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had the exact same problem with my scoot, exactly the same symptoms decided to die before my CBT, if i took off the diaphram cover then put it bk on the bike would start but die as soon as you give it throttle. i changed the carb and all the stuttering and cutting out stopped. so i would say its definatly the diaphram thats causing the prob.
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Well the diaphragm appears in perfect condition and correctly sealed, all jets clear, still not even a put when I spin it over, have a spark, have fuel in the float bowl, have air, wouldn't even fire with some easy start!
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check your valves.
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You mean inlet and exhaust in the engine?
Cranking with carb off and hand over manifold it sucks my hand in hard, so exhaust at least must be OK, harder to check the inlet!
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No, blue meant check your valve clearances. In the top of the engine at the front under the seat, look for the valve cover.
Unless they are way off i wouldnt think it was this but its worth checking if you tried everything else.
This is a strange one ??? Everything seems good yet it still wont fire up :-\
Off to do some more head scratching, post back later if i have a brainwave :)
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I will check the clearances, as it only happened after a period of running (to start with) I guess it's possible they have closed up a bit and as they warm up jack open, doesn't sound 100% likely though......
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check everything battery post tight. charge the battery up. check fuse. make the 2 bolds by the carb are tight make sure the 2 rings around the carb are tight. go threw and thingten what you thing needs tighten up. just dont over tighten.
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also check all the hoses for leaks............or replace.
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Thanks, I am experienced with cars, all that has been done, thing isit ran fine for 100 miles and then started to do this after shorter and shorter runs, most things suggested are black and white failures, this appears a shade of grey!
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Finally got the cam cover off and the valve clearances are down to nothing so will reset them (and try and get the snapped stud out!), what should they be (searching not helped yet!)
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OK found a thread (not sure why search wasn't finding it) clearances reset, but still won't start, spins over fine, has spark at the pluf, has fuel in the float bowl of the carb and in supply hose but not a dicky, not even a stutter.
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(and try and get the snapped stud out!), what should they be
are you talking about the engine studs?? the one that hold the rocker arms and cylinder and head in place. they need to be torqued down to 1.8/2.2 kgf-m or 13 lbs to 15.91 lbs of torque.
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...what stud is snapped, and since yo've said it twice, how do you know there is fuel in the bowl??
..open the airbox, remove the air filter (clean / inspect) and spray a one-half second burst of starting fluid into the carb's intake tubing..
..try to start engine..if it fires, then your jet(s) are most likely clogged...
..btw, dont rev your engine while burning starting fluid, and shut it off as soon as it fires!!!
..that stuff burns really hot and, along with the increase in air-flow, causes an extremely lean combustion condition...
peace
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..also, check the fuses in the batteery compartment..
..they are 7amp glass AGC type automotive fuses...
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Fuses checked a long time ago.
I know there is fuel in the carb float bowl as I've had it off twice and each time fuel comes out!
Snapped stud was one holding the breather to the head, no biggy right now if the engine won't start!
No joy with easy start either, not a cough.
Plug in HT lead laid on engine, lots of nice bright sparks.
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If you still have that spare cdi then maybe try that in just to rule out the cdi thats in there?
If you got spark, got fuel, got air etc its weird it wont fire ???
Only thing i can think is its not taking the fuel out the bowl properly but then i wouldve thought spraying the easy start in wouldve gave it a little idle at least.
Wheres Zombie..........ZOMBIE.......
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The spares CDi went on there that first afternoon at the roadside!
I've blown through all the jets, all seem clear.
What I find most strange is the way it ran for a while before losing power and then cutting out, then each time running for less time and taking longer to re-start which would normally indicate a relatively minor issue, but nothing seems to stack up. I've worked on plenty of cars and never have I had anything like this, at least if it's coughing and spluttering you can try stuff to try and make it better, this is just dead!
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Only other thing i can think of is a blockage or bad fuel line somewhere but since it had fuel in the bowl and still wont fire at all i cant see how it could be that either ???
Its even bugging me now to find out what it is.
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take the gas line off the petcock and turn the bike over to see if gas well come out.and also the other air lines going to the tank make sure they are working ok. check gas filter. how is the seal on the gas tank cap.
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Filter blown through, fuel flows from supply hose when cranking (with it off the carb) all first day checks...
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Compression test. I bet a valve is leaking.
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Thats a possibility, unfourtanetly I don't have my tester right now, exhaust I'm reasonably confident is OK (and usually the more likely to have an issue) due to the suction on the manifold when spinning the engine over, harder to test the inlet of course, clearamces were too tight (like nothing) though which isn't good.
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I had an intake valve go bad, and it was all the same symptoms. Just get an ebay head for 30-40- bucks, and be sure to ask the seller FIRST if it has steel valve seats. If not find another
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OK local shop just got back to me, low compression.
As I'm off on Business next week and taking her to and from work costs about £8/day more than the Scoot I'm probably just going to suck it up and get them to fix it.
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Bummer but at least you know whats wrong now.
So what caused it to happen do you reckon? Did they say?
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No, guy who collected said he thought it turned over a bit easily (It's always been quite easy, first and only 50cc I've ever worked on so assumed it was 'normal'), they ran a quick comp test and its come back very low (didn't ask for a value), they'll probably have the head off later today or tomorrow.
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Well keep us posted how it works out. Hopefully they get it fixed up ok.
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i still reckon there will be a problem with it even after they try to sort it. i had the EXACT same problem with my scoot. everything checked out fine compression wise, but it was the diaphram in the carb that was letting it down, somthing had happened to the diaphram so the slide wouldnt work properly hence no fuel getting to the engine and it constantly cut out. when i fitted the new carb i had no more probs with it and it ran fine. if you were to get a new slide and diaphram i bet it would work a treat.
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Well the Diaphragm was good when I checked it is all I can say!
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Well the Diaphragm was good when I checked it is all I can say!
We'll find out soon enough, whens it due back? End of the week maybe?
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No idea yet!
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Well the Diaphragm was good when I checked it is all I can say!
mine looked in top shape when i had the carb in bits but the slide wouldnt work and the bike still wouldnt start. which would suggest that the diaphram wasnt working properly.
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Rings piston and bore shot, rebuild cost horrendous so will have to look at DIY I think, how hard is it? Any ideas where to get a kit from UK?
http://www.ebay.co.uk/itm/KYMCO-AGILITY-50-4-STROKE-ALLOY-CYLINDER-AND-PISTON-KIT-/270659042035?pt=UK_Motorcycle_Parts&hash=item3f04893af3 (http://www.ebay.co.uk/itm/KYMCO-AGILITY-50-4-STROKE-ALLOY-CYLINDER-AND-PISTON-KIT-/270659042035?pt=UK_Motorcycle_Parts&hash=item3f04893af3)
???
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Rings piston and bore shot
..woww...did you see them?
..how many kilometers and what year of scoot??
..this will be the first time i can recall hearing of an un-modded piston failure on an agility...
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8500 miles (about 13000km) did come with no air filter and had been messed with but seemed OK, apparently had run low on oil yet it had only done 130 miles since I topped it up so can only assume the rings were on their way out and it burnt it all!
Think I'll get it back and get that kit if people think it will fit OK....
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did come with no air filter
..aahhh...that explains it...
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Yes, seemed to run OK, not burning oil (visibly) and told it had only just fallen off...
So will that kit fit and will I need new mains and possible crank do you think?
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That kit seems expensive, maybe im wrong but im sure a 72cc kit is less than that so wouldve expected the stock 50cc to be cheaper?
The seller is good tho, i can vouch for them. I got a load jets, plugs and other bits & bobs off them and was always a quick delivery and good parts.
Maybe try CMPO website (chinese motorcycle parts online) they may be cheaper.
Think the guy who sold you it mustve known it was on its way out and passed his problem onto you? Or maybe it was just co-incidence.
I bought mine when it had around 7,000km and, touch wood, its been great so far, up to about 22,000km now and feels better than wheni got it.
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CMPO are dearer for a 50cc kit, the oversize kits are cheaper (and cheaper than that link)
Maybe knew it was using oil, don't think he knew it was that bad.
I'll get it home, see what else it may need and get that kit then.
Bugger it!