Intro and background

[gsx600racer]

Hello all, long time reader first time poster.

I have a 2003 zx50 with about 8k km. Purchased last November. Was in need of some cosmetic repair. It was all stock other than the CDI de-restriction.

It was missing front turn signals and rears had missing lenses. I wired the fronts that were “built-in”with parts from a donner scooter. For the rears I just swapped harness to built-in ones.

It ran when I picked it up but had intermittent spark when going thru it inside a heated garage. I gave up on it till this past spring(was working on another scooter project) I went thru all electrical and could not find anything wrong. It would run on cool days and not warmer days, or ran good for awhile then died.(when things warmed up under the seat) So for the hell of it I took CDI out and put it in freezer for a couple hours and it would run again. I did this several times with consistent results. Replaced CDI and all is well. Maybe this info will help others when troubleshooting this issue. Was always under the understanding that CDI's work or don't work.

Anyways rode it this season and loved it. Acceleration, getting to cruising speed, and climbing hills are decent. For a 240lb rider I was impressed. Cruising around 40-42 on the flats, downhill almost 50, and decent hills 32-35mph.

MODS,

Replaced rear tire, was worn really bad on left hand side of tread. What a mess, previous owner used fix-a-flat. Tire was hard to un-seat bead from the rubberized fix-a-flat inside. Would recommend tire slime over fix-a-flat.

Have swapped out drive boss with Naraku 36mm. The one I swapped out was 36.94mm long.
Replaced drive belt with Gates PL20601(732x18.5x28)
This mod seem to take away take-off speed but did gain a tiny bit on top end. I put the old belt back in and seem I regained take off. I understand that the old belt is worn and sitting lower in the variator pulley and take-off is improved.

Wife and I both ride, she rides a 2001 Honda elite 50sr(the crazy restricted one)
I have de-restricted this scooter. Removed plate behind variator, removed(drilled out) washer in exhaust, de-carbonize exhaust(that was fun), up jetted carb, open up stock air box, and tie wrapped oil injector pump wide open(no second cable to oil pump. Runs great just smokes a bit at idle(oil pump wide open all the time)
 
Well that is where I am at and a little about myself and ventures with scooters.
I really have enjoyed this forum, a lot of great reads, advise and people.

[zombie]

Welcome to the forum 600.
You have a good handle on these things. For the ZX get yourself a Jasil Top Racing variator, and a Bando OEM belt. The ZX uses a shorter drive boss It is the ONLY Kymco that uses it. I think it is a 34 mm. This will gain you around 5 mph, and much better take off.

I have an insane ZX that ran 82 mph last year. It's been sitting in my shed ever since.

[blytzkegger]

Thank you so much for posting this! I am going to order a new CDI for my Agility 125. I have only had it for a week and the previous owner has not ridden it for 4 years. I changed the fuel filter, oil, spark plug, wire, and checked the valve clearance and it really runs like a dream. Except on hot days. It will run great and then just up an die. If I wait a few mins it fires right up and runs perfectly fine. I have checked quite a few things and I was wondering about the CDI but most things I have read said it's either good or bad - yours was the first post I found that was an in between like mine. Hopefully it will fix it and I really appreciate you taking the time to post this. It may have saved me a massive headache!