KB is the off road version of zx

[Blacky]

Hello and thanks for a great forum 
i have found this forum and its great fun to read about kymco models. i own a KB (same as zx but with off road tires), its the same scooter, both models share the same frame engine parts and variator. i also own a B&W 250.
i have installed on my KB (zx) the following: big bore kit, rear pully 2000 rpm springs and tourqe spring, open air filter and a larger main jet (actually the original jet was drilled), and iridium spark plug. i will install a quicker variator soon. all electric parts have been refreshed to new ones.

since the installment of the big bore kit the idle rpm is not reducing on stop after an intense ride. i can get the performance parts rather cheap since i am in good relationship with my mechanic. he claims that i need to lose the open filter and install back the original air box. since i lost the original air box and i need to buy a new one just for trying solving this rpm issue, i prefer to invest my money on something else for my scooter. but its really impossible to keep on riding like that since on every stop light the scooter is extra jumpy.

can anyone give me an opinion what to do next?
thanks 

[thebatman]

what up? welcome to the forum.....i had a similar issue recently, my return to idle sucked, took forever..the mix screw needed to be set at 1 turn out, then adjust idle according to your taste...fixed it right there.....if the scoot wants to jump, the idle is off or your fly springs are getting weaker....hope any of this helps...post back any results.......

[thebatman]

oh yeah blacky...if you have changed all that..NO WAY put that oem box back on..youll restrict the scoot again and be wasting that money from mods..what exhaust are you running?? yours definately needs to breathe now...who makes the kb??  kymco??

[Blacky]

Thanks Bman, i will try following your advice first thing tomorrow morning. can you please advise me which of the carb screws is the "mix" screw? i know the idle is tuned with the top screw on the carb isn't?

KB is made by kymco, same scooter as the ZX. my scoot is a year 2000 model (yep totally old).

the weird thing is that the idle rpm goes wild only after riding for few miles. after start and when the auto choke is turned off, idle is tuned perfect.

still runing with the stock exahust. i have made sure its in good condition and not cloged with burned oil.

i have been thinking about installing a bigger carb and a new exahust to complete the modification. can you write what adjustments have you done on your ZX?

[art]

  Hey blacky welcome to the forum your crazy idle is most likely the air idle mix is to lean. It should be the only other adjustment usually a little left of the idle set screw,not familiure with the 2000. But turning in ritchens it and out leans usually.

[thebatman]

yeah, turn the mix screw, that should fix it, (thanks art..lmao)..smaller one under the bigger idle screw..have you drilled any holes in your exhaust or beaten out the catalyitic converter??...wordslinger drilled 6 3/8 holes in his pipe..i had cut a hole,beat out the converter, welded back up on my oem exhaust... dont think i have ever seen a kb..cool.. my mods are slight: upgraded tires, unrescrited(boss drive,cdi)..adige clutch(4 now,have motorio to put in) w/1000malossi contra, 1500flys..race var from s.a on ebay(heavy as hell)w/7g rollers(4 now,thinking 6.5), technigas next r chrome exhaust, shaved head for squish, open filter w/rejetting.(made my own jet,around a 94).....have polished belt cover, chrome grips, integrated eruo turn signals front/back,red running/speedo lights,removed stickers..i think thats all... next list is: port reed cage till i get one, port exhaust(pay someone for that job..lmao), then bout a 17mm carb i guess..advoiding bbk for now anyway, want a bad stock..lmao 

[thebatman]

i cant believe your getting by with the oem carb anyway, if you have a bbk on that..yeah, get a bigger carb/exhaust..the technigas is a good one but ppl say the technigas rs2 is better(is bigger, for 70cc+ bbks).. z is running a 28mm carb on his zx(many more mods than i..lmao)..shaka has a 19mm on his...

[art]

 Some of the older kymco's have real honda type carbs,may be ok. the 2000 peoples have the real deals you can like set the neddle and everything 

[thebatman]

did not know that...i need me one of THOSE carbs...lmao

[art]

 yep I think word and dru have them.someone does on a 1999 and a 2000. Was talking about the carbs and shim trick and they had no clue what i was talking about 

[thebatman]

lmao...i didnt either.      wondering if I should try it...

[art]

 It may help your just off idle pick up.

[Blacky]

Wow, thanks for your replies guys its warmimg my litlle kymco's heart. i didnt try changing the mix screw yet, i am delying it for the weekend, i am using my other scoot this week due to longer distance rides. i will be posting the results here..

reading all the modification on Bman's scoot caused me to start making a wish list

i have drilled only one hole on my stock exahust. for Bman: did you "open up" the exhaust and just took everything that was inside out? (catalytic converter) making the exhaust all empty inside before wellding it back?

i know the original weight of the rollers is 9g, when installing a race variator what will be the rollers weight that i want for me to achive a better take off rather then better top speed? i am using this scoot in city limits only. i didnt understand if you have mixed rollers or not 
on ebay i see race variators for the zx that comes with 9 or 8.5g included in the variator set.

i wish i was in the states, its such a hussle to modify my kymco here in israel. can you belive i need to pay extra tax plus a certificat from the official goverment offices (something similar to DMV) for every vehecile parts over 50$ when reciving a package from e bay! we dont have a lot of stores of race parts here.

p.s: is it really possible to change the speedo light to red (or blue)? i just need to open the plastic covers? is the color determened by the color of the LED only?

thanks a lot everybody 

[art]

 You can make it any color you want with the right paint     I forget the recomended one.

[wordslinger]

..i cut my exhaust open, cut out the cat-con...and part of the baffle..welded it all back up...

..i now have drilled the holes in the bottom and that was the best thing i could have done all around, to my exhaust, other than replace it...