ZX50 Rescue! It's Alive!

[hellish100]

Just brought home a 2004 Kymco ZX50.

Before opening it up, I can tell why these are desirable. Glove box and under seat storage, lots of room for small and large riders, 12in wheels, front disc brake, the list goes on.







This example has been sitting and needs attention:
8k miles  Km
Does not run ( it gets spark! )
Needs tires
Lights don't work
I need to remove random stickers that were applied by previous owners.

But overall:
Doesn't look to have been dumped at speed
Plastics look to be in good condition
New Battery ( supposedly )

My plans for it?
Get it cleaned up and running.

Stretch goal:
Big bore kit
Pipe
19mm or 21mm carb ( but I read that these vertical motors require bigger carbs than what would be needed on the equivalent bore mina? 

This is a departure from the horizontal mina stuff that I'm used to. Pics to come!

[hellish100]

I finally got the stickers removed!

There is some play in the headstock. I'm not worried about it....yet. I'll take apart the headstock to snug it back up.

Pics!

[chadbullet]

Sharp bike! I've been lusting after one of these myself.

I think a 21mm would be fine if you're going 72cc. I'm using a CP21 evolution on my Polini Contessa AF16. I don't think I'm at it's limitations as far as performance is concerned. 24mm PWK definitely seems to be most popular though.

[hellish100]

Feb 14, 2022 9:19:46 GMT -5 chadbullet said:

Sharp bike! I've been lusting after one of these myself.

I think a 21mm would be fine if you're going 72cc. I'm using a CP21 evolution on my Polini Contessa AF16. I don't think I'm at it's limitations as far as performance is concerned. 24mm PWK definitely seems to be most popular though.

Thank you! I hear these things are quick in stock form so I want to see what that's all about before I change anything.

Updates:
-Shot some pre-mix down the carb and it will cough over a few times. Yay!
-Snugged up the nut that holds the bars on. It's a 32mm or 1 1/4in socket. That got rid of the play.
-I followed dexameth 's instructions to delete the rear turn signals. They couldn't have made that any easier!
-Chopped the rear fender. It really cleans the rear up.

The front integrated turn signals do not have provisions for a socket so I'll have to do some research. If anyone has experience on that, please educate me.

Next steps:
Drain old gas
Drain injection oil ( I'm going pre-mix ).
Clean carb

More pics coming soon.

[dexameth]

I did the front mod as well... here's a little video explaining it. I forgot to mention the socket fits into a recess in the plastic assebmly - what I meant by "it all just pulls into place"

the plastic is "punch out", where the wires go thru you can either drill or just punch out with a philips screwdriver.

[winner3ty]

I love zx50's! they all pack a great punch, and have a very enjoyable ride. I have a Polini Contessa 72cc and CVT bits for mine (which need to be installed some time this spring) and also an Arrow exhaust.

I would say you should try some trim restoration gel, as yours look like they need it. here's what mine looks like for reference

Stock exhaust is fine, but its like a boat anchor, so heavy compared to a performance pipe.

[hellish100]

Thanks!

I was looking at the Arrow pipe but wasn't sure if it would clear the plastics. It looks like it does. Decision made

[winner3ty]

Feb 26, 2022 15:15:51 GMT -5 hellish100 said:

Thanks!

I was looking at the Arrow pipe but wasn't sure if it would clear the plastics. It looks like it does. Decision made

Plenty of room, had to remove the reflectors though, cuts it too closely to the pipe. wraps around the air shroud well. also will have no rubber stopper for the center stand. Also a must is to replace the allen bolt for the silencer, strips out easy and is too short.

[hellish100]

Okay, I need some help.

I cleaned the carb, put in a new spark plug and nothing, not even a pop. The plug is seeing fuel.

I am not familiar with these vertical Honda motors at all! So I removed the carb, intake and reeds, sprayed more fuel into the crank case. Only then did it pop out of where the reeds should be.

Could the timing be off?

Compression is 115PSI.

[aeroxbud]

Compression is quite low. But should start.
Did you have the throttle open when doing the test?

[hellish100]

Throttle closed.

After messing with it more got it to putt a few times when holding WOT. When it does, it smokes back out the carb. It's not like a backfire, but it doesn't feel right. I like my yYamahas so much more.

[winner3ty]

When these run right, they are great engines. sounds like yours has had a rough past.

[hellish100]

I'll keep it around but I can't justify spending money on it right now. Could the exhaust be plugged up?

[benji]

Mar 7, 2022 20:40:37 GMT -5 hellish100 said:

I'll keep it around but I can't justify spending money on it right now. Could the exhaust be plugged up?

This is common on the Honda scooters, so this could be the issue. Also, check the reeds. They could go bad and still give you some compression. I think this is the newer better version of the Honda af18 motor, but not entirely sure.

[hippo008]

These are essentially long case AF16E motors. It should be noted that the intake ports for the ZX motor are notably smaller, it could be worth opening those up for better flow.

These AF- series veritcal motors are interesting. You can get a lot of great parts from China and Taiwan for them. Its possible to build a very cheap but still fast and reliable scoot on this platform.

A lot of people do an upgear kit on their Honda motors, however I dont know if these motors can take Honda secondary gears. I would suggest looking into it.

Youre right about the carb sizing. With the intake port being located off to the side of the crankcase you tend to get poor filling. Its not uncommon to see people running 28mm PWK style carbs on street setups. I personally run a Polini PWK24 on my Polini Corsa setup. Works great.