KymcoForum.com
Scooters - 50cc => zx50 => Topic started by: Calvert50 on August 17, 2009, 05:58:56 PM
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I'm having an issue with the ZX-50 kick starter. This is a 2003 model. The machine fell over and jammed the mechanism. I took it apart and nothing is broken. The circlip got pushed out of place and the kick starter return spring mechanism went "sprong". I have the service manual, and put everything back together per the diagrams. However the kick lever return seemed weak, and the gravity seems to pull the lever enough so that the kick starter "driven gear" engages the engine and makes metallic scrapping sounds when you hit bumps. The manual does say "check for a weak spring", and since it says very little else, I figured that was worth replacing. Five bucks later I have a new spring, but it has all the same angles as the old spring, and it just doesn't seem to have enough umph to hold up the rather light weight of the kick start lever, and once again, while it works and starts the engine, when you drive down the road, bumps and gravity pull the lever down, thus slightly engaging the kick starter "driven gear".
What I'm wondering is whether the kick starter return spring should be spun up one turn to add tension. The shop manual says nothing about this. I've lubbed up the "driven gear" shaft to make sure it's not sticking in the "engage" position. It appears that the spring is made to just be installed without adding one revolution of tension, which I tried to do, and it's virtually impossible to do that, and just didn't seem to make sense. Though the additional tension would solve the problem I think if I could wind it up that tight.
Anbody run into this problem?
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Hi, All these spring return type doo-dads require a pre-load to work. I replaced mine about six months ago, and had a bear of a time getting it together. It just took patience, and a small screwdriver to hold the spring while assembling.
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Zombie...
Thanks for the hint. That was one of my theories, that the darn spring had to be wound one turn to be effective. That makes sense. I tried that with the old spring, and couldn't get it. It kept exploding out of the brackets. I bet at the factory when they do the one wind, they have some kind of tool to make it easy.
So just to reiterate. The spring has to be tensioned one turn up from neutral. Ouch...that ain't gonna be easy.
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You got it man. Just watch the finger tips!
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Can anyone provide more detail regarding the small screwdriver? Pictures would help me out a great deal here. I already took it to 2 different scooter shops in town, one of them being a Kymco service center. They were pretty clueless on this procedure. Which notch or hole does the spring connect to on the half moon gear? Does the spring have to be below the top of the part of the case where the kick shaft goes through? I must have spent a whole 8 hours on this so far, coming up short!
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I tried different ways of putting it together. As far as spring placement on the half moon gear, I tried one maybe both of the notches, I tried the hole. I tried preloading the spring, I tried not. No matter how I put it together, it won't kick over when I put it on the bike. So that makes me think.
I eventually consulted the manual and found the correct way to hook up the spring, but it's just a 2D view and doesn't account for how the spring should look under the half moon gear. Very frustrating. I tried shoving it down and around the shaft bushing area (kick starter spindle forcing part, according to the manual) on the case, but that seems impossible. All it says about a screwdriver is "If the hooks of the return spring can not be installed properly, use a screw driver
to press them into their locations respectively." And that's not my issue at all, putting the spring hooks where they belong is easy without a screwdriver.
All I know is a) my spindle has endplay b) my spring won't wrap around the forcing part (isn't it supposed to?) and c) no-go on the kicker!
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Just saw this Youtube vid: how to put together a chinese scooter's 49cc gy6 kick start assembly (http://www.youtube.com/watch?v=P98dNPTzihk#)
Which helps a great deal. I guess the secret to finding that was searching for a scooter kick start assembly rather than a zx 50-specific kick start assembly. Since they're all real similar it doesn't really matter. The only worrying thing I can think of now is that I may have overextended my new spring and it may never sit flat like it should. I'll let you guys know how it turns out in a couple days.
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I was pretty vague in the responses I gave. Yes it does have to be wound 1 full turn, and it seems impossible to do but you just have to be patient, and have more brains than the part. The toughest bit is getting the spring to seat on the boss without jamming under the 1/2 gear.
It's been awhile but as I recall I turned the 1/2 gear PAST the seat point, and slowly allowed it to return while using a flat head screw driver wedged between the gear, and the spring to work it down as I allowed the gear to return to the set point.
Where it sat when you had it too loose is where it sits when it is properly pre loaded. seems impossible but that is what it is.
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I don't think the fault is with the kickstart spigot (driven gear )
To double check, lift the spigot out then whilst holding the cvt cover in one hand, pull the kickstarter as if it's being kicked and have an assistant drop the spigot in. Slowly release the kick
Start handle and the spigot will drop
Against it's spring. The cvt cover can now be refitted.. Before you do though, make sure your starter
Bendix is fitted correctly as these can rattle against the outer variator if they are not fully home
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I finally installed the kick start mechanism properly in the belt cover. The video really helps, and using the kick lever to rotate the kick gear really helps too. When I put it back on the engine, it won't move. When I got it, it was missing the "special washer" that goes behind the crankshaft nut. Not realizing how special it was, I bought a regular flat washer and threw it on. That could be the whole reason why I'm not getting movement - not enough clearance between the crank nut and the driven gear. So a new special washer is on the way. The other thing it could be - correct me if I'm wrong, it's not right in front of me - is the 3 slide pieces I just installed on the variator plate. I got them from partsforscooters for some reason. Oh yeah, getting parts from kymcopartsonline is a nightmare, that's right. Anyway, those were an extremely tight fit and not the exact shape they should be. Not sure if the thickness is any different though. It's a Malossi, and when I got it, those pieces were missing. Would that hurt anything? I'm thinking it's better to have no slide pieces than the wrong ones, maybe. On top of that, I ruined the threads on the crankshaft, twice. Might be looking at a new one of those, too. Wish me luck!
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Please post up picts. of what you are describing. I have a ZX, and have no idea what you are referring to.
I'd get a Die to clear up the crank threads. You really don't want to swap the crank. Just bring the nut to compare for the die size.
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Sounds like you already know what I'm talking about. I already re-threaded it with a die which worked at first, but then my dumb ass had to crank on it some more just to show my friend the engine still turns over. Then the new nut got stripped. Not sure about the threads on the shaft actually, I was planning to run the die over them again just to be safe. Come to think of it, when I was cranking on it, I felt a good deal of resistance. Like maybe the wrong slide pieces or sliding rollers in there. 16x13 dr. pulley though. I absolutely agree the last thing I want to do is replace the crank, though!
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16x13 is the right size. There is a specific way they install tho. You have to get that part right.
Installation of Dr.Pulley Sliding Roller.wmv (http://www.youtube.com/watch?v=kee3aQWINss#)
If the shaft is stripped you can cut new threads to any size you want. It is easier than replacing the crank, and much cheaper.
I'm still not clear on the washers, and such...
All those parts have to be exactly what is installed at the factory. You can use whatever after market stuff you want but the OEM shims/washers/spacers have to be used in the correct order, and placement.
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OK well the special washer is part 98. It is described as WASHER SPECIAL 12MM. Anyway, if the washer I got at the hardware store is any different in specialness / thickness, then that could be when my kick start doesn't work. Same with the nut. But, since my engine doesn't want to turn over smooth (since installing the new sliding rollers), then I very well could have installed those wrong. Easily. So thanks for the vid there, I'm definitely going to use that soon.
Side note: The reason the threads got stripped, so I thought, was only because I mistakenly used an impact wrench on the nut. But, in retrospect, stripping the threads was made easier by the fact that whoever was in there last, left out the washer! So they snugged the nut all the way down the shaft, effectively screwing up the end of the threads. Lazy.
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Makes sense...
One more thought... If you replaced the drive boss/Variator it HAS to be ZX?DIO specific. They use a Shorter drive boss than every other bike on the planet. The GY6 stuff fits but if you combine the longer drive boss with a missing CVT cover gasket it will force the toothed kick start gear into the kick start crown on the cover.
I have been using Jasil Top Racing variators for awhile, and Highly recommend them.
PS the ONLY thing special about that washer is it is thicker than a standard 12mm washer. You could use two standard to get the thickness of the OEM but be sure to use some blue Lok Tite on the nut.
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OK well I don't know which boss I have but I can tell you that it worked fine before (the kick start). Before that fateful day when my spring came loose. So it had the unknown boss (aftermarket), no washer, half a gasket. Just got word from kymcopartsonline that they changed the special washer and nut to a single piece flange nut. Which they threw in with me start relay for waiting so long. Slowly but surely...
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Nice. I would get the new gasket for the cover too. I had the same issue I described above. Just that 2mm makes a difference.
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You can always shim your cover also with washers on every bolt between the cases. Sounds like a nightmare of a time with a kicker cover.
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I think Batman shimmed his case cause of the same issues.
The ZX is an odd ball engine design. (Dio Clone/AF18)
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Good points, there. Well I followed the video on installing the dr. pulley sliders, rethreaded my crank, installed together with new kymco washer and nut. Put the cover and gasket on, and nothing. Same problem. True I have a Malossi variator, and a straight boss, BUT it all worked together before my belt snapped. It had worn out roller weights in it, seems to be the only difference. Slightly worn starter gear parts. All I can think of now is maybe I should replace my sliders with rollers? But why? Why would my sliders not work? OK I lied, there's another thing I can think of. The 3 piece slide parts I got for my variator. I got them because when I took it apart, there were none. Unfortunately I got them from a generic scooter part supplier and they barely fit the plate. So I guess my next move is order the stock piece slides and stock roller weights and then see what happens. I'll try it first with the no piece slides with stock roller weights. Then if that doesn't work I'll try stock piece slides with stock roller weights. Then if that doesn't work I'll try stock piece slides with sliders. Then if that doesn't work I don't know what else I could be doing wrong.
Edit: just saw that shimming technique you guys posted. Might have to try that first!
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Finally got it started. Turns out it was 2 things preventing it from starting. The first being my half moon gear's spring no longer looks nice and straight like it does in the manual (installed). So the whole kick start mechanism was taking a ride with the crank when I tried to electrically start. So I swapped covers for my other cover that doesn't have any kick start parts. Then second, realized (actually I realized this first), the engine was flooded with oil. How much of it was from unsuccessful starts and how much of it was from who knows what, maybe a leaky oil pump, I wasn't sure. Because when I tilted her over and cranked out the excess, it left a good size puddle on the cardboard floor. Anyway now my main concern is getting the oil out of the exhaust. Any helpful hints on that? I know it has oil in it because the cylinder did, and plenty of it escaped through the intake side as well. So, if I know there was oil coming out the spark plug hole, and the intake manifold, and now you have to scoot it with your foot in order to get the engine to rev up, then that makes me pretty sure I have an exhaust to clean out. Any helpful hints on how to do that? Just run it out? Degrease it?
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What a mystery machine. You know what? I'll just have to get back to you guys on this. I mean, I drove it at least 10 miles and there's no smoke coming out of the exhaust. So, what I'm thinking the reason for my slow takeoffs is either:
1. faulty fuel valve (I have a rusty fuel tank)
2. too much grease on the slider weights
3. carburetor issue
You can see a nice amount of oil leaking out the air filter, which I would expect from twisting the throttle. When you twist the throttle, it opens up the oil pump as well as the carb. So I don't know, sounds like a fuel issue. We'll see.
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Replaced fuel tank, fuel valve, fuel filter. All the old parts were rusted or affected by rust, even though the valve and the filter were pretty new. Well, with fresh gas and no more incoming rust particles, still the same result. Dreadfully long takeoffs. I'm thinking it's somewhere in the variator or carb. We shall see.
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Update
Bought a new race variator kit from Scooter Assassins for less than 40 shipped. Bam! Takeoff problem solved. Still have no clue on the kicker. Just got done trying my new spring. Still haven't tried shimming the cover though. Anyone know the proper recipe on the shims? Washers aren't terribly expensive so I guess trial and error on that is my next move. Only thing is, that would entirely defeat the purpose of a gasket. So all kinds of crap that doesn't belong would be headed for the belt and the parts around it. Anyone want to buy an electric starting ZX 50 in Sacramento? Goes 55 on slight downhills. 50 on level. All the lights work! Everything works, just not the kick start. Lots of nice new parts on it.
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When you installed the kick lever return spring... Did you give it one full revolution to pre load it?
It's a bear to do. You almost need three hands but if it is not pre loaded the lever will simply flop around, and land on the drive pulley.
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Well the first spring I did, or tried to. Then I saw that video of a probably Chinese kick starter being installed. No such preload on that one. My first spring looks messed up now that I tried to wind it that far. So I got a second one. I may give it another shot. Spent a real long time on it already.
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The ZX is different than the rest of the scoots. It's an old school Dio copy (af-18).
That spring does need one full turn. I use the moon gear to spin it, but you have to have it almost completely installed before turning it because it will constantly climb up onto the gears shaft, and make pushing the gear/shaft down into place impossible. It usually takes me 3 or so attempts to get it done.
What may help is using a pair of vice grips on the splined section outside the case. Just be SURE they are kept square, and they don't botch up the splines. If they are too loose or too tight then the shaft/gear is garbage.