KymcoForum.com
Scooters - 50cc => Agility 50 => Topic started by: fabio on December 08, 2012, 12:24:27 PM
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Hi
I've recently purchased a Kymco Agility 50 (in the UK) and i'm having some problems with it, namely the rpm at idle is erratic......
To explain what I mean....sometimes it will idle sometimes it wont.....sometimes it idles at 1800 rpm, sometimes at 4000rpm, at other times less than 1000 and then it dies. The idle can move up and down as if its "hunting" but always ends up dying.
To try to sort the problem.... I've taken the carb apart, disassembled and thoroughly cleaned it, I've soaked the jets overnight and blown them out till they're clear, I've cleaned the air filter, I've adjusted the idle screw, I've adjusted the fuel/air mixture screw, I've checked for good fuel delivery, I've checked that the throttle cable isn't hanging up, I've tested that the Auto-choke works properly, and I've changed the CDI just in case.
The Agility starts first time every time (with the throttle half open) and then there is very little acceleration to it (its de-restricted both at the boss, the CDI and it has a 85 MJ, however the problem was no different with the stock 80MJ that it previously had installed)
Help!!!!!!!!!!!!!!
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A bit more info...I've just taken it around the block and it will hit 45-50 downhill and about 25-30 uphill, on the flat it approaches 40ish. It takes a great deal to time to get up to any of these speeds though >:( so perhaps I need to look at replacing the clutch springs and the contra spring once I've got the idling problem sorted.
I must admist then when it was running just around the block it ran well, so i think my carb problem is perhaps isolated to the idle circuit, as the choke circuit and the MJ circuit seem to be running well.
Another quick question...when you start your Agility from cold does anyone know what the idle speed should be (i.e. the idle rpm until the choke turns off and the engine revs drop a touch)
Thanks
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Does the idle rpm also go up and down when you don't touch the throttle after a successful start ?
Or does the "hunting" only begin after "blipping" the throttle one or more times ?
I've had problems like these because of the carb slide sticking, took me a while to find out...
I was lucky to see that the slide was still open when I disconnected the air hose after stalling the engine one time, but it spontaneously "unstuck" as soon as I noticed, and the engine was running fine again... So I might as well have never found out that there were a few grains of sand in the air hose, making the slide stick every now and then...
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as far as your spped try changeing your rollers try 5.5 or 6 gram rollers.mine starts with out turning the throttle.but on cold days I need to let it worm up good befor I take off. what size carb do you have try a 19 or even a 20 works great. also check your manfold bolts to see if they are tight the smallest amount of air comeing from there well bong the scoot down.
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Does the idle rpm also go up and down when you don't touch the throttle after a successful start ?
Or does the "hunting" only begin after "blipping" the throttle one or more times ?
I've had problems like these because of the carb slide sticking, took me a while to find out...
I was lucky to see that the slide was still open when I disconnected the air hose after stalling the engine one time, but it spontaneously "unstuck" as soon as I noticed, and the engine was running fine again... So I might as well have never found out that there were a few grains of sand in the air hose, making the slide stick every now and then...
Hi
It goes up and down on its own and then dies.. touching the throttle makes no difference and also after a run it makes no difference....that's why I think that its got something to do with the idle circuit of the carb, I had a close look at the slide when I took the carb apart and it looked very "free" with no drag at all....a couple of thoughts that I've just had are to check that the needle isn't bent (but I'm sure that it isn't) and to re-check that the diaphragm at the top of the carb isn't holed or compromised in any way
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as far as your speed try changing your rollers try 5.5 or 6 gram rollers.mine starts with out turning the throttle.
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Its got 6.5gr rollers so I think that I'll take it down to 6.0 and try it and then 5.5 and try it
Mine starts from cold without throttle, but when warm it need the throttle....
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What size carb do you have try a 19 or even a 20 works great.
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Its the standard CV carb, I have got a Dellorto 17.5 PHVA carb that i was thinking of trying but I wasn't too sure if this will work with the Kymco's set up?
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Also check your manifold bolts to see if they are tight the smallest amount of air coming from there well bong the scoot down.
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Yep they're tight and I've used WD40 around them and the rest of thew carb and associated pipes to test for air-leaks all to no avail
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Sounds like an airleak on the carb manifold. Check the hard right angled rubber manifold that comes from the carb and bolts onto to the engine, if it has a loose clamp or bolts it'll let air in kr the same happens if they split. Revs and idle goes all over the place. It may have split at the clamp that holds it onto the carb if you overtightened it. Best to remove the manifold completely and check it properly, mine split underneath before and i couldnt work out the problem for a week or so till i found it.
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Just popped into the garage to double check - unbolted and removed the manifold and checked it - no crazing or cracks, the o ring looks good too and it was tightened down well.
More head-scratching!
Any thoughts anyone?
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...and, I've removed the top of the carb again to check the needle (that is not bent) and the diaphragm (that is not holed), I've re-seated it with a bit of grease to make sure that is sealed well too.
Still no joy though....
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try to recap the plug to 06. to o7. and see if the plug is showing good spark. this might be a sign of your coil going bad to if so I would get a nkg coil they are more trusting........
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His Agility starts first time every time, so I guess there's nothing wrong with the ignition itself. It might need a new plug though, it's possible that it has an insulation fault that doesn't show when cold, but my money is still on a carb/air leak issue...
@fabio : did you have a look at the plug right after the engine dies ? If you clean it before starting (preferably when the engine is warmed up, so the choke is off) and check after it died, it can tell whether you have to look again for an air leak or blocked passage in the idle circuit (clean plug), or whether it's running way too rich from e.g. a damaged idle mixture screw seat (black soot on the nose and/or top of the threads)...
Also, have you checked the float level and reliability of the float valve ?
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If you have a few extra dollars I would just throw a new carb in the scoot and by pass the other issues.
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Aaaaargh!!!
Just took the carb to bits and cleaned it all out again - the sodding thing wont start at all now !!!!
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New carb. but calm down you well be ok new is better,try a 20 mm carb you well love it. the take off is great.
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New carb. but calm down you well be ok new is better,try a 20 mm carb you well love it. the take off is great.
Took it apart and got it going again, the idle jet was loose - but still the same idle problem - its got me thinking...I wonder whether the idle jet is tatered - it was blocked when I first took it apart and I've cleaned it that many times I'm wondering if I've enlarged the bore and its now too rich and that's why its stalling??
Thoughts?
(Also - do you have a link for a 20mm carb that would do the job?....or ideas for sourcing one? - thanks !!)
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monsterscooterparts .com has some. I got mine from theam in about 3 to 4 days.
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I think I've just found an inexpensive one on ebay ;D
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Remember and check it has the right jet size in it. Should be 82 for a stock derestricted scoot.
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Remember and check it has the right jet size in it. Should be 82 for a stock derestricted scoot.
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Yes will do - I've got a selection of jet sizes and threads from my adventures with Vespas.... http://modernvespa.com/forum/topic73471 (http://modernvespa.com/forum/topic73471)
Fabio
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Not sure the Vespa jets will fit, you may be lucky tho.
Nice scoots in the link, you still got the vespas and the Lammy? I just finished building a T5 classic into an older looking vintage sleeper.I might keep a mental note to p.m you at some point if i ever need some Vespa advice.
Think this links to pics of my build, ive just got a lower sports front shock to bring the wheel up more into the mudguard cos the T5 one thats on it in the pics spoiled the vintage look.
https://www.facebook.com/media/set/?set=a.262146780501179.59170.100001175782324&type=1&l=ddee87f4a5 (https://www.facebook.com/media/set/?set=a.262146780501179.59170.100001175782324&type=1&l=ddee87f4a5)
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The threads on the GT125 may do cos its uses a Keihin CVK - jets prob too big bored though IIRC
Vespa.....No, they've gone I'm afraid...
This is what I had up until a couple of month ago.... 1997 Vespa ET2 70cc (the one in the link), 2006 Vespa GT125, 1983 Vespa PK125, and a 1964 Lambretta Cento.....they've all gone now
Currently I have........ 1988 Kawasaki GPZ500, 1984 Honda CB125TDC, 1997 Piaggio NRG MC2, and most recently a 2008 Kymco Agility 50..................
I always buy non-runners or ones that have stood unused for a while, then get them going and sell them on (most usually for a small profit)
PM me if you need any help...or indeed over at Modern Vespa they are pretty knowledgable on Vintage Vespas too in the NSM section
Fabio
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Cool. Nice bike collection. Yeah i joined modern vespa and few others, havent been on much tho, tbh they seem a bit of a weird bunch on the vespa forums, maybe its just me? Doesnt seem as friendly and fun as on here. They do have some useful info on there tho.
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Cool. Nice bike collection. Yeah i joined modern vespa and few others, havent been on much tho, tbh they seem a bit of a weird bunch on the vespa forums, maybe its just me? Doesnt seem as friendly and fun as on here. They do have some useful info on there tho.
Prob cos most of them are US based ;D
Mind you having said that I found some of the most annoying users on the site were UK based, in particular there were a handful of UK based MVers that were very self-righteous!
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Sounds about right. Last time i went on i got moaned at because i prefered to bolt my floor runners on rather than use an official Vespa factory punch and rivets :D
I just got pissed off when some guy riding a chop had a go at me for modding MY vespa the way I wanted ::)
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I started a topic about windshields and was told maybe a scooter wasn't for me..!
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Seems typical for every forum that has to do with something that's connected to fashion or zealotry, like e.g. Vespa's or high-end audio... You're either in or out, cool or uncool, knowing or ignorant... The kind of people that will turn anything into a competition, just trying too hard to be somebody...
I guess that's one of the reasons that this forum is so relaxed, Kymco is just not a fashion thing... 8)
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I guess that's one of the reasons that this forum is so relaxed, Kymco is just not a fashion thing...
..th kymco is a machine...and should be treated as one...
..they perform, and performance wears things out...
..this forum is the best thing i've ever found on the internets...
8)
....welll...there was this one sight with naked people...that was kinda cool...
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...and you also find on there a little clique of people who find it funny to abuse newbies - I always tried to help new users out with the little knowledge that I'd got - and I must admit I got great enjoyment from that.
What was really funny... was that I started a thread on trying to get a 50cc modern vespa to go as fast as I could without spending much money and I got 2 kinds of comments/PM.
Here is the thread......... http://modernvespa.com/forum/topic73471 (http://modernvespa.com/forum/topic73471)
The first kind of comment was from every rider who had a 50cc who thoroughly enjoyed my challenge and helped me along or learned something from me. With that group of users there was a great level of comradery.
The second group were the vespa "purists" or the "I only ride a 200cc" users or "oh no I don't approve of riding a modern" type....the comments were sarcastic, rude, heckling and downright nasty!!!
Ok rant over....nuff said. :)
Fabio
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They just dont get it. Us 50cc riders are just pond scum to them. Most of them wouldnt know where to begin modding a 50cc.
For me i like both my scoots for different reasons. Vespa for having fun, going long runs and speed. Kymco for commuting, reliability, cheapness and ease of use. Vespa is away till the weather improves, hes my thoroughbred, kymco rode me to work this morning in the sleet , shes my workhorse ;D
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The replacement carb has landed in the post today - so hopefully tomorrow I can get it fitted.
I've opened the float bowl and the first thing that i noted that was obviously different was that the idle jet on the new carb stands proud of its location tube.... whereas the idle jet on the old carb sits deep inside the tube so it shrouds the jet (maybe this is why I was having idling problems me thinks? - maybe with the jet being shrouded it was struggling to get a good and regular supply of gas?)
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I've opened the float bowl and the first thing that i noted that was obviously different was that the idle jet on the new carb stands proud of its location tube.... whereas the idle jet on the old carb sits deep inside the tube so it shrouds the jet (maybe this is why I was having idling problems me thinks? - maybe with the jet being shrouded it was struggling to get a good and regular supply of gas?)
Nope, it's just a different design... (unless it isn't and they just didn't turn it into place all the way, of course 8) )
With the actual passage being only .35mm diameter or so, it definitely won't struggle for gas... The .35mm opening is the limiting factor by design... Any shrouding around it will relatively be such a small hindrance to the flow that it's completely negligible...
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The replacement carb has landed in the post today - so hopefully tomorrow I can get it fitted.
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Right! - that's done it !!!
I fitted the replacement carb after swapping the jets out of my old carb (MJ is a 85, IdleJ is a 35) and using the old auto-choke, and after tweaking the air/fuel mix and the idle speed I've got it to settle down to a fairly even idle at about 1800 rpm, so I'm quite happy. I'm guessing that it was the old carb itself that was at fault - total cost for the replacement carb was £6 inc postage so I'm even more chuffed.
Next job is to get the transmission cover off and replace the rollers (well lighten them any way - what I did with the vespas that i was modding was to drill out the spare material of the rollers a bit at a time to get down to the right weight, then I've already got some stiffer clutch springs and a stronger contra spring both of which aren't specifically for a 139Q engine but I think will be close enough to be suitable
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For the price of a set of rollers and having less hassle its easier to just buy a new set. Stock is 6,5g, i found 5.5g work well for me, also like 5.1g or 5.3g for acceleration but i did lose a few mph top end so went back to the 5.5's for now.
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I must admit I think I've already got some 5.5g rollers in the garage with all my scooter bits somewhere - I just need to put my hands on them.
Until I find them I'm not so sure of the physical dimensions though, if i remember they were 19mm wide and the outer diameter 16mm, I'm not too sure until I get the variator off what the stock physical dimensions for the Agility are.......
I know that the ones currently fitted are stock because the previous owner had them renewed when he had a service done not so long ago - the invoice says 6.5g rollers fitted.
On the MJ front - the stock one I had was an 80 and I bought an 85 - do you think this may be too big? I haven't done any plug chops as of yet but when I popped around the block on it earlier this evening it sounded a bit flat as if it was a touch rich.
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..all kymco 50cc rollers are 16 X 13...
..a50 oem wts are 6.5...
..some 5.5s will work well...
..i never tried any dr pulley sliders in my a50s, but i love them in my s9!
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..i'd put my money on an 82 mj being closer to optimum...
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..i'd put my money on an 82 mj being closer to optimum...
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Yes good!!, I've just ordered an 82, I re-read a few older threads on KF and found out that 82 was prob the best for the UK.
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Ok - the transmission cover is off....I've got a "waz-hammer" so the variator and clutch nuts came off without too much hassle.......
The variator is off and the boss is the de-restricted smooth one....but the rollers have sizeable flat points on them (probably one of the reasons why the acceleration is total pants). I've weighed them and they're 6.5g. I've ordered 5.3g Narakua ones.
I've removed the clutch and undone the clutch holding nut and released the torque spring, cleaned up the plates and replaced the spring with the one I'd already got, its a white one which felt a touch stiffer than the slightly rusty one that came off.
The springs that I'd got in mind for replacing the current 3 clutch springs were not quite right so I'm going to order a set of 3 strength Naraku ones (9 springs in total, they are in 1000, 1500 and 2000 rpm strengths) so I can trial and error a bit.
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Stiffer contra spring AND lighter rollers ? You'll probably run the poor machine right into the revlimiter all the time :o
Better try to change only one thing at a time, CVTs are a bitch to get right otherwise...
And take small steps only, from 6.5g to 5.3g sounds like a lot to me. My experience is that a difference of 0.25g is already noticeable in most cases (unless you're running into the revlimiter, but then it gets hard to tell any difference anyway...)
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A new carb for £6?! Where did you find this I can only find ones on eBay at around £36 :( this must be the problem with mine the idle is mega high then it just drops and dies and will only start with a little throttle then as soon as I go for any throttle again the revs just drop.
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Stiffer contra spring AND lighter rollers ? You'll probably run the poor machine right into the revlimiter all the time
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Yes I'm probably being a bit too severe there aren't I ?
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A new carb for £6?! Where did you find this I can only find ones on eBay at around £36 :( this must be the problem with mine the idle is mega high then it just drops and dies and will only start with a little throttle then as soon as I go for any throttle again the revs just drop.
Ebay - new old stock - http://www.ebay.co.uk/itm/121020873883?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649&clk_rvr_id=427017325959 (http://www.ebay.co.uk/itm/121020873883?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649&clk_rvr_id=427017325959)
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Forgive me but just so I'm clear, I need M5 threads for my stock carb jets? Flame away :P
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Forgive me but just so I'm clear, I need M5 threads for my stock carb jets? Flame away :P
Hi JC
Yes M5 (I think that its best to use Keihin threads cos they are slightly a different pitch to normal 5mm threads) - I ordered the Keihin variety ..... Keihin M5/5mm
Fabio
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[Edited for more clarity of information]
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Damn they haven't got any more of those carbs left :( looks like im gonna have to pay £36 for a new one :-\
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Stiffer contra spring AND lighter rollers ? You'll probably run the poor machine right into the revlimiter all the time
5.5g rollers with 1500rpm torque keeps my revs around 6500-7000. 5.1g rollers with 1500rpm torque kept me around 6800-7200rpm. Think the rpm sweetspot is around 6800-7000rpm. Been running like this now for well over a year with no problems. I cant get up hills as fast on anything heavier than 5.5g, no matter what rollers to torque spring set up i tried, and i tried a lot :D
But like Mono says, do one thing and ride it before doing another. Otherwise you have no idea what the problem is if you just throw a load of new gear in their all at once.
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5.5g rollers with 1500rpm torque keeps my revs around 6500-7000. 5.1g rollers with 1500rpm torque kept me around 6800-7200rpm. Think the rpm sweetspot is around 6800-7000rpm. Been running like this now for well over a year with no problems. I cant get up hills as fast on anything heavier than 5.5g, no matter what rollers to torque spring set up i tried, and i tried a lot :D
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I'm glad you've clarified that for me... my thoughts were that 5.5g was the recommended roller weights that I had read about when coupled with a 1500 torque spring...I'm a touch heavier than the 8st lads that run most scooters (with being a bit older, hehe !!) so slightly lower at 5.3g would do the trick, or am I going a bit too mad with this???
Thanks in advance
Fabio
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Sounds right to me, but no 2 scoots are ever the same as im sure you know. 2008 models seem to work well on 5.5's but 2010/2011 models aparently rev way too high on 5.5's? Or so we have been led to believe on here?
Like i said i ran Malossi 5.1's for a while, also on the 1500 torque and it was fine too, higher revving but it suited me for hills around my way and better acceleration too from stopped. Only reason i went back to 5.5 was i lost 4-5 mph top end on the 5.1's (unless downhill).
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..coold have compensated for that top loss with slightly shorter boss, or maybe slightly longer belt??
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The loss of top end might also be caused by running too far into the revlimiter, that costs a lot of power...
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..coold have compensated for that top loss with slightly shorter boss, or maybe slightly longer belt??
Already on a 36.8mm boss :D
The loss of top end might also be caused by running too far into the revlimiter, that costs a lot of power...
Nah, dont think so for mine. Revs didnt go past 8000rpm even on long flats, usually sits around 7800rpm once its up and running on a straight. Goes up to near 9000 downhill tho. Just simply doesnt have the power to get the higher revs and speed on the flats since its only a little 50cc im sure. Im not too bothered, cant expect miracles, it get me around with reasonable performance for what it is and itsceap to run.
I did used to run a 736 belt on the stock boss, which gave similair results to using a stock belt and short boss, was going to maybe try that again but on the short boss. Far too cold to work outside now tho and i got the other scoot in my garage to lower it right now. Will get round to it eventually. :D
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Even without a revlimiter the power will drop above 7500rpm (with stock camshaft that is)...
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Even without a revlimiter the power will drop above 7500rpm (with stock camshaft that is)...
I reckon im fine cos it only gets up to 7800+ after im up to speed anyway, all the way from 0-45mph it stays around 6800-7800 usually depending on the gradient of the road. I could prob go to 5.6 or even 5.7g and maybe shave a touch off the revs but it works fine for me how it is. I ride the same route every day so its set up perfect for that, if i go anywhere else i take my bigger scoot or the car.
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I do fancy trying a better torque drive later so i may have to retune again after that. The only other mod im considering is a BBK but my sons getting to use it next Sept once hes 16 so i need it as a 50cc for him.
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Ok
The stuff has all arrived.... and its fitted....
- 82 MJ
- 5.3g Naraku rollers
- 1500rpm clutch springs
- stiffer torque spring
and I'm very pleased indeed!!!
- I sounds brighter (it sounded a bit flat before) so I guess that's the main jet (I'll have to do some plug shops at the weekend)
- It holds its take off slightly higher (not as high as I expected mind you - I went with the 1500rpm clutch springs so I'll see how I go on once they've bedded in a touch - if not then I'll fit the 2000rpm ones)
- Acceleration is a bit more responsive and i can actually hear the revs rising now as it speeds up - before it just chugged along disappointingly.
- It goes up hills at around 30ish now as opposed to around 20ish !!!
Impressed.....the only thing left to sort is this.....when its idling on its stand, when I take it off the stand (with no revs being altered) it stalls? What's that all about?? ???
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...thatsa pretty good setup fabio!!
when its idling on its stand, when I take it off the stand (with no revs being altered) it stalls?
...my 08 did that if i dropped it off the stand pretty quick...
...so i started just easing it down...no problem....
..never did worry about it after that....
..my experience with "2000" flys, created too high revs at takeoff....
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Q - when its idling on its stand, when I take it off the stand (with no revs being altered) it stalls?
...my 08 did that if i dropped it off the stand pretty quick.....so i started just easing it down...no problem....
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Yes that was going to be my plan too...but I'm fascinated now..... why does it do it??
Fabio
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Sounds like youre almost there :)
I cant say i felt any great improvement on mine with the clutch springs, i use 1500 ones. I found the 2000 springs just too stiff so didnt use them.
Plug chops should be fine on the 82 jet but it may be worth doing just for peace of mind.
Just double check you got the air in and mixture out tubes tight on the carb. Mine had an airleak before and idled like yours now, fine on the stand but lower it and it used to die. Was due to the carb manifold leaking for me.
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Mine had an airleak before and idled like yours now, fine on the stand but lower it and it used to die. Was due to the carb manifold leaking for me.
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I did have an air leak hiss on the manifold last night when I first put the carb back on after replacing the 85MJ with the 82.
I removed the manifold and had a good look but couldn't see any cracking, crazing or similar that could cause a leak - I used a bit of tape under the clamp to pad it out and it seemed to stop the hiss....perhaps I need to take a look at this again?
Another question.... the manifold vacuum connection that draws fuel from the petcock goes to a tee-piece...what is the box on the left that is also connected to the tee-piece?
Fabio
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Just a bit more info.....
I decided that the carb still wasn't right...... after i couldn't understand why it cut out when I took it off the stand.
Also the idle wasn't perfect...and I couldn't accept that in my mind as being correct either.
So, I removed the carb again to investigate....thinking that the idle jet was perhaps blocked slightly..... here's what I found....
I removed the carb from the scoot and turned it upside down and removed the carb fuel bowl, removed the idle jet and took a look through it up to the light in my garage....it looked slightly blocked.....I'd previously bought one of these..... http://www.ebay.co.uk/itm/Carb-Jet-Cleaner-Tool-Kit-Car-Boat-Motorbike-Scooter-ATV-Carburetor-Cleaning-/160943325772?pt=UK_Motorcycle_Parts&hash=item2578f8424c (http://www.ebay.co.uk/itm/Carb-Jet-Cleaner-Tool-Kit-Car-Boat-Motorbike-Scooter-ATV-Carburetor-Cleaning-/160943325772?pt=UK_Motorcycle_Parts&hash=item2578f8424c) .....but hadn't used it on this particular carb.....so i gave it a quick go and the jet cleaned out nice and easily.
On refitting the carb fuel bowl I noticed that the gasket was a bit dis-formed so I trimmed it a touch to ensure a better seal.
I also refitted the manifold (including a spot of copper grease on the joints between the inner face of the manifold and the outer of the carb) and ensured that the clamps were nice and tight.
On starting the scooter up I noticed that it seemed to sound better (the idle rpm was higher - perhaps because the idle jet was cleaned out properly now)
Also, the adjustments I started to make to the air/fuel mix screw were now also translating into the more expected results that I previously couldn't achieve.
So.....it looks like I'm almost there......I've left it to cool for a couple of hours or so and will start it again later this evening to see how it reacts from cold
Fabio
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Nice. You might find you need to fine tune it again a bit depending on the weather where you are now. I tend to have mine so its perfect on dry days, on wet days it runs a little rich but im riding slower in the rain anyway and rich is better than lean.
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Streido - thank you for all your help - very much appreciated !!