2013 Agility 50-72cc

[JayAre]

Bought a 13 Agility 50 last year 25mph tops then put a 72cc big bore kit in it this year, still sloooow. Started looking at the intake, exhaust, & transmission & what is Kymco thinking? 18mm carb with a 16mm intake manifold, a restriction in the intake tube between the carb & the air box, & another on the intake of the air box. Has anybody massaged/ported the intake & head to 18mm? Took a grinder to the tube & air box to see if this helps. Then cut the 5/8' exhaust tip off & welded a 1" on the muffler, the pipe leading to the muffler is 3/4". I have a derestricted CDI & coil coming that should help the 6.5 gram rollers work. Also the belt is about 3/8" into the driven clutch, that's like trying to start off in 2nd gear. Ordered a 20mm longer belt. I may be a newbie but I've been racing/playing with snowmobiles for years & always run the top of the belt to the top of the driven clutch not below it. Drive clutch controls the rpm's, driven the shift, does this sound like I'm on the right track? Thanks for any help!

[BettinANDlosing]

Do you have a 2t agility? They never offered that in the USA, but if you do the engine should be the same as the People 50 2t or vitality etc etc.

[JayAre]

Don't know what a 2T is, 2 stroke? Bought this in northern Michigan, the U.P. It's a 4 stroke, with a 18mm Kymco CVT carb. Will be putting the longer belt on today we'll see that, the intake & exhaust mods help. Still waiting for the CDI

[BettinANDlosing]

First you should be using the OEM Kymco belt. Secondly everything maintenance wise ok? Valve clearance good, you'll have to do this more often with s kit. Did you pry that restricted bushing from the intake? You'll gain a lot of performance if you get a larger carb on there. Also what speed are you getting? If your going 50 out of it I'd be happy.

[souzamoto]

As B&L said, you should not use a longer belt. fI you have yet to "Re-Restrict" the Variator shaft on the front pulley, that would need to be done first. You will need to remove the restricted spacer and replace with Kymco #2000 spacer. I guess there is an aftermarket spacer also? The CDI box can be modified by grinding 5 to 6mm bevel across the lower edge of the box facing you. (with the harness plug in at the top facing away from you) This will sever the restriction wire. I don't think you need a different coil.
Replace the main jet with a #85 if only these mod's are done. You may need to go larger with airbox mod's
CJS

[BettinANDlosing]

As B&L said, you should not use a longer belt. fI you have yet to "Re-Restrict" the Variator shaft on the front pulley, that would need to be done first. You will need to remove the restricted spacer and replace with Kymco #2000 spacer. I guess there is an aftermarket spacer also? The CDI box can be modified by grinding 5 to 6mm bevel across the lower edge of the box facing you. (with the harness plug in at the top facing away from you) This will sever the restriction wire. I don't think you need a different coil.
Replace the main jet with a #85 if only these mod's are done. You may need to go larger with airbox mod's
CJS

If its kitted you'll want to be larger than #85 jet, into the 90s easy.

[JayAre]

Here's what I found... The Kymco manual lists a 20mm carb, mine has an 18mm, The jet is a 90, again the manual lists a 85 for stock, Pilot is as listed, 35. the plug is black. I'll be testing the enrichner next if it's good I'll jet back to an 85. I'm also thinking after market 20mm carb & do something, port or replace the restricted 16mm intake, anybody know of an after market Intake? The longer belt, Gates 748x18x28, seemed to help the bottom end/engagement & upshift but it's bogging because of jetting too much gas.
And yes I have a derestricted variator sleeve. The valve clearance I went with .003" bigger than the manual spec .002" that seems tight?

[BettinANDlosing]

Here's what I found... The Kymco manual lists a 20mm carb, mine has an 18mm, The jet is a 90, again the manual lists a 85 for stock, Pilot is as listed, 35. the plug is black. I'll be testing the enrichner next if it's good I'll jet back to an 85. I'm also thinking after market 20mm carb & do something, port or replace the restricted 16mm intake, anybody know of an after market Intake? The longer belt, Gates 748x18x28, seemed to help the bottom end/engagement & upshift but it's bogging because of jetting too much gas.
And yes I have a derestricted variator sleeve. The valve clearance I went with .003" bigger than the manual spec .002" that seems tight?

IDK if you have the correct manual, the valve clearance is .004" or .1mm. Where did you measure the carb diameter? when it says 20mm (which I also think is the wrong spec) that measn 20mm venturi, not 20mm spigot.

[JayAre]

I downloaded a manual for a 2013 50cc Agility everything looks the same in the pics as what I have. Valve clearance spec .002" seemed tight & that's why I went .003". I'll reset them to .004". The carb measurement, I made at the outlet where the butterfly is, this is the spigot? I'll measure the slide, that would be in the venturi. It still seems very restricted in the intake manifold at 16mm being just after the 18mm carb spigot. Terms are a little different than what I'm used to with snowmobiles, motorcycles, & cars. Thanks for the help everyone!

[JayAre]

Wow! I bought this moped form the dealer with 13 miles on the odometer. The carb's slide diaphragm was folded into the chamber & a cover screw is stripped so it looks like someone has been in it. Also the auto bystarter/enrichner/choke, pulls 15 ohm, 10 max is spec. Hooked it up to a battery & it never closed off the port. So the auto bystarter not closing off the extra fuel & the slide not being able to lift because of the diaphragm is passing vacuum I think I've found the problems. Going to talk to the dealer tomorrow we'll see how that goes! Checked my manual it does list the valve clearance at .04mm for both valves .048mm converts to .002". Seems like everything else I work on has a 10% larger clearance on the exhaust more heat more growth? Probably over thinking it. Thanks B&L for your insight!

[BettinANDlosing]

Wow! I bought this moped form the dealer with 13 miles on the odometer. The carb's slide diaphragm was folded into the chamber & a cover screw is stripped so it looks like someone has been in it. Also the auto bystarter/enrichner/choke, pulls 15 ohm, 10 max is spec. Hooked it up to a battery & it never closed off the port. Measured the slide at 18mm+ the radius cut would be around 20mm in the venturi. So the auto bystarter not closing off the extra fuel & the slide not being able to lift because of the diaphragm is passing vacuum I think I've found the problems. Going to talk to the dealer tomorrow we'll see how that goes! Checked my manual it does list the valve clearance at .04mm for both valves .048mm converts to .002". Seems like everything else I work on has a 10% larger clearance on the exhaust more heat more growth? Probably over thinking it. Thanks B&L for your insight!

Good job tracking that down, seems like they had to do a carb clean before selling you the scooter, and messed it up pretty bad. I just double checked (it's been a while since and agility 50 has come in for valve service) and indeed is .04mm, which is very tight but trust the service manual. Sorry for misleading you! Interesting thing is 99% of the other Kymco scoots have .1mm clearance, but like I said best to trust the service manual I guess. Keep us posted on how it feels after they get you a new diaphragm.

[JayAre]

The dealer has ordered a new auto bystarter for me covered under warranty but that's 7-10 days out. The float level was set at 13mm & spec is 17mm, more gas. I'm surprised the bike even ran! Went to my local Artic Cat dealer & ordered 92.5, 95, & 97.5 jets I'll have those in 2 days. Going to put it back together Once all the parts are here with the float set at 17mm & a 90 jet.

[JayAre]

Just received my warrantied auto bystarter from the dealer & installed it with a 95 jet, reset the float level to 17mm, & straightened out the slide diaphragm. Also have the 20mm longer Gates belt on it to get it to the top of the driven clutch sheaves. This 72cc BB 4 stroke is running with our 50cc 2 stroke Zuma's & will out pull them on a hill. Haven't tried it for top end yet as I still need to read the plug to see where the jetting is. I'll get a few miles on it varying the rpm's for the break in before it gets thumped on to much. Once I get the derestricted CDI I'll check to see if the rpm's go up at all.

[JayAre]

Still on the lean side white plug & it starts popping out the exhaust wide open at 35 mph. I will need to order some bigger jets, 100, 102.5, & a 105. The longer belt gives it better bottom end/acceleration, but it may be hurting the top end. Hard to tell while it's running so lean. Hurry up & wait some more, hopefully I can get jets by Wed. Also received my derestricted CDI & will be installing it at the same time.

[JayAre]

No jets yet so I bought a #60/1mm drill bit & made a 100 jet. The plug is dark brown/little on the rich side. But now it's surging during acceleration so I tried to raise the needle but there's no e-clip or slots to make an adjustment. It has a lock over the needle with a spring so at best I may be able to add 1 small washer to lift it. They've made it tamper proof for EPA/emissions like what they did with the pilot screw. This is going to be a hard carb to tune! I may be better off to by an after market conventional slide carb & toss this CV/emissions carb.
So moving on I then plugged in the brand new derestricted CDI & blew a fuse as soon as I hit the starter. Must be a sign so I'm done for the day. Going to look for a different slide/diaphragm with an adjustable needle & slotted pilot screw on the internet or maybe a pre-emissions CV carb. This carb is cast with Kymco on the side but it looks just like a Keihin.