ZX-50 Kick Starter

[Calvert50]

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?

[zombie]

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. 

[Calvert50]

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. 

[zombie]

You got it man. Just watch the finger tips!

[patrick328]

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!

[patrick328]

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!

[patrick328]

Just saw this Youtube vid:

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.

[zombie]

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.

[naughty lee]

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

[patrick328]

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!

[zombie]

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.

[patrick328]

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!

[zombie]

16x13 is the right size. There is a specific way they install tho. You have to get that part right.


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.

[patrick328]

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.

[zombie]

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.