Agility 50 Performance Upgrade Report

[adkbiker]

I bought a used, restricted, 2014 Kymco Agility 50 and would like to share my progress so far at performance upgrades and welcome any helpful comments:
1.   Replaced variator boss that has the shoulder with a smooth boss obtained from scooter assassins on ebay; absolutely need to do this to achieve a few more mph.
2.   CDI: Did not need to “cut wire” as described in earlier models.  Kymco must have changed CDI design as once boss changed and carb change below no problem getting faster speed and did not notice any restriction.  I tried two replacement CDIs.  The orange DC one from scrappydog did not work, engine would not start.  They said must be something in Kymco wiring.  I bought one off ebay advertised as non rev-limiting and the scoot ran but hill climbing performance was much worse.
3.   Obtained a CVK 20 Carb and performance air filter with splash guard from scrappydog.  This was simple to install but two issues to be aware of.   
a.   First there is a rubber tube out of the front of the bowl that goes somewhere, I don’t know.  I plugged it and it ran OK.  Any thoughts on this let me know.  There was no documentation with the carb and I couldn’t find anything online. 
b.   Second, the crankcase breather tube out of the valve cover to the old air filter box was simply routed under the seat and left open.
4.   At the same time I installed the carb I installed a scrappydog orange performance coil/spark plug lead.  I’m not sure how much that may have helped.
Performance is markedly improved; particularly throttle response.  Still slows up steep hills but it is only 50cc and I weigh 190. 

Since I ride often on gravel roads I swapped tires out for knobby Maxxis M6024 tires and they work great.

Next I plan to replace complete engine/trans with scrappydog 80cc engine/trans as I think this will do better on the hills, not looking for a lot more top speed.  However, I think I will need to swap stator as I notice wiring out of the 80cc engine has an extra wire.

BTW, an electric impact wrench works great to remove variator and flywheel nuts.  Before removing nut I mark location of nut/bolt alignment with permanent marker and carefully re-tighten to that mark.  I have a Makita XWT02Z that has 3 settings, the lower setting providing a bit more control when re-tightening.

Any comments or ideas please respond.
Thanks,
Michael

[tortoise]

Was there an intake manifold restrictor?

! No longer available

[adkbiker]

Yes, I forgot to mention that.  I removed the restrictor (large washer) from the intake manifold when I changed the carb.

[JayAre]

The tube off of the bowl could be the over flow? If it is just route a tubel off it downwards by the back of the motor. As for the breather that's to help make a  vacumm in the crankcase & scavange any blow by/emissions. I would try to filter it somehow to keep dirt from entering the engine.

[adkbiker]

See line out of carb below left of intake, provide tube runs under my hand.  When running there is vacuum so I'm guessing intake manifold vacuum line for some purpose no used on my scoot.

[JayAre]

Some bikes have a vacuum line to a fuel shut off so your carb can't flood/overflow when the bike is off. You could follow the fuel line back to the tank. My Wifes 2013 has one on the bottom of the tank where the fuel line attaches. But if your bike runs without that line in the carb hooked up to anything you should be good with it plugged off.

[adkbiker]

Thanks for the explanation, engine seems to run fine with it plugged.

[Elvedin]

If you want to ride faster uphill, then you should get performance variator. I've been completely satisfied with Naraku High Speed, which I obtained from Racing Planet, but the price may be a problem if you prefer used parts.

[adkbiker]

Thanks for steering me to Racing Planet, some good stuff there!

[adkbiker]

OK, so I’m going to go for it in the next few days and swap out the 50cc motor for the GY6-80cc motor I bought from scrappydog.  I keep procrastinating because the GY6-80 has an extra red/black wire coming out of the stator that I don’t have on my engine.  I know a lot about engines, carbs, and gears but electrical sh** is a mystery.  I read that there are 8 pole and 6 pole stators, DC fired stators, not to mention 6, 8, and 11 pole magneto flywheels.  I’m not sure what to do about this.  So, I think I’ll just remove the flywheel and stator from the stock engine and see if I can install it on the GY6-80 motor. 

[adkbiker]

Now that I have the old engine out and trying to install the new ScrappyDog GY6-80 I ran into a major problem with the rear spindle. On the new engine it is much longer than on the old engine (see pics) and not sure what to do at this point. The spindle can probably be swapped out, any advice please let me know!

[adkbiker]

I resolved this by taking both gearboxes apart and swapping the spindles.  During re-assembly of the scoot I notice that the rear shock mount is about 3 CM further back but I think that will be OK.  This does mean the the stock air filter box will no longer work but I am using a different filter anyway.  The last hurdle is exhaust as the upper exhaust mount is further back on the case than the stock Kymco engine.  I have a Stainless Steel system, but the bottom bracket of the header doesn't quite line up either.  I think I can make either work with some adapter plates.  If I use the SS system, I'll have to run a piece of flat metal or something back from the exhaust mounting bolts on the case to support the SS muffler and rear fender.

[adkbiker]

I finally managed to complete the ScrappyDog GY6-80 engine swap.  It started right up after a couple cranks!  I had to cut and modify the SS header mounts (see pics above) plus fabricate a horizontal mount along the right side to support the muffler.

I've put about 25 mi on it so far.  It is getting stronger as it is breaks-in and is putting a smile on my face.  It meets my objective to climb hills better and cruise comfortably at 30 mph (the top speed limit for this class of motorcycle in my state). I have some steep hills on paved and gravel roads near my house and the scoot is much stronger.  There is a really steep off road hill in back of my house I couldn't climb with the stock motor, no problem with the new motor.  I don't know what the top speed might be, but it now accelerates nicely to 30 mph and cruises comfortably there at reduced throttle. 

The SS muffler is a bit loud for my liking and I've re-installed the stock exhaust system.  The SS sounds nice, but I don't just don't want to attract attention.  I really can't detect any loss of performance for my type of riding but probably some at WOT. 

In the end I am very happy with the results even though the engine swap was a lot more work than expected.

[paceneedsstides]

nice read I had seen you post on 49cc didn't know you were here too.