Kymco Like 50 - 4 Stroke - Upgrade

[c.stroe]

Hello everybody,

I bought a Kymco Like 50 4 stroke in March 2017, brand new. I haven't found a dedicated forum thread for my scooter, so I am asking my questions here.

My scooter is restricted, most likely the CDI is restricted as I do not exceed 45 kmh even when riding down hill.

What I want to obtain is:
- 70, maximum 80, kmh top speed;
- a little bit more power when moving from stand still or when passing small cars.

As I do not want to spend a lot, while I know nothing about scooters, I was thinking of buying a derestricted CDI and a 70cc kit.

Could someone recommend me what to buy?

I am a plain financial analyst, wearing a suit while riding the scooter and taking the subway when it rains.

Thank you,
Cristian.

[245luigi]

Tough question because 2T performace theory is different to 4T performance but I would imagine 4T upgrades on other Kymcos should generally be the same across all the bikes.

I think your only option is a Big Bore Kit as I believe exhausts provide marginal improvement. I imagine you would have to increase carb and jet size along with that then tune the transmission and call it a day

Luigi

[c.stroe]

Hi Luigi, thank you very much. I was actually wondering whether you could point me what to buy. What CDI? And what big bore kit? Because I know nothing of these things, I have only heard about Malossi and Naraku.

Thank you in advance,
Cristian.

[245luigi]

Cristian,

Use this website http://www.racingplanetusa.com/scooter-parts-sh-1.html . Select your vehicle Manufacture (Kymco), Model (Like 50 4T KG10AA), then product group.

Engine Parts has BBK under Cylinder Sets Racing. Seems like the engine is a 139QMB. Any scooter that has a 139QMB engine will contain relevant theory.
 
There are kits made by 101 Octane, Airsal, Naraku, Malossi, Naraku, and Polini.
http://www.racingplanetusa.com/kymco-like-kg10aa-engine-parts-c-2_21286-1.html?newcPathco=25

http://www.49ccscoot.com/bbk.html

According to this webite: http://www.scrappydogscooters.com/139QMB_50cc_Performance.html

Your engine is the same as these KYMCO bikes (Kymco Agility 50 Kymco Agility MMC 50 Kymco Filly 50 Kymco Vitality 50 KYMCO Filly KYMCO Nexxon 50 KYMCO People KYMCO Super 8 KYMCO Vivality KYMCO NEW DINK 50 KYMCO Yager KYMCO Yager GT).

Even though you have a LIKE, you can go on these forums and see what upgraded configurations are being run. They should apply to your bike but confirm part fitment using racingplanet usa.

[c.stroe]

Thank you, Luigi, for your help. I've discovered that this website is very useful. In addition, the assistance they provide helps you decide what it's best to buy.

The conclusion is that I have ordered an unrestricted racing CDI, a Malossi Multivar 2000 variator and a Naraku 70cc Kit.

I will post here later on what is the outcome of the upgrades.

Best regards,
Cristian.

[c.stroe]

Hello,

I just wanted to revert with the outcome of the improvements. In the end, I installed a Naraku unrestricted CDI and a Naraku 70 cc kit. The start from a stand still position is very good, basically I am faster than any car.

Very good acceleration up to 35-40 kmh.

Top speed 60-70 kmh. However, I do not really ride at 70 kmh, 60 kmh is enough for within city limits as I manage to move around at the same speed as the other cars.

Consumption hasn't increased, or at least I haven't noticed.

Best thing is that now I can ride safely on the second (or third lane) without having to worry about passing cars.

[c.stroe]

Help please, I do not know what to do.

I used to upgrade my scooter and had the following improvements:
- Unrestricted CDI, unrestricted variator boss;
- 72 cc Naraku Kit: https://www.racing-planet.de/cylinder-kit-naraku-v2-72cc-for-gy6-kymco-50cc-2v-p-101917-1.html?backcPathco=16&cPath=26_11792;
- Malossi Multivar 2000 Variator with 6g rollers;
- Secondary transmission gear up kit 17/49: https://www.racing-planet.de/secondary-transmission-gear-up-kit-top-racing-18-17-49-for-china-kymco-4-stroke-p-260390-1.html?backcPathco=5&cPath=26_11792;
- Main Jet 82.

The scooter was fine, being able to reach up to 75kmh.
However, it pulled up really slow and didn't do much good inside the city.
And, due to the high compression, the kick-start wouldn't work.

So, I installed an 80cc kit from Airsal: https://www.racing-planet.de/cylinder-kit-airsal-sport-813cc-50mm-for-139qmb-gy6-50cc-kymco-50-4-stroke-p-270391-1.html?backcPathco=16&cPath=26_11792.

After this upgrade, the scooter was pulling even slower and the top speed dropped to 65kmh.
Why is that?

I understand this kit has a lower compression.
It is true that now I can kick start the scooter.

After the 80cc kit, I installed a 19 carburetor with 33 pilot jet and 85 main jet: https://www.racing-planet.de/carburetor-replacement-for-4-stroke-139qmb-qma-p-98831-1.html?backcPathco=16&cPath=26_11792.

It was a bit better.

Then, I just went back to the stock secondary gear kit.

Now:
- the scooter pulls a bit better;
- maximum speed is 65 kmh and it revs very high, the scooter actually trembles at maximum speed;
- consumption is 3.8 litres per 100 km (that's 61 mpg).

I wanted to install a sports air filter: https://www.racing-planet.de/air-filter-air-system-metal-gauze-filter-38mm-straight-version-blue-shield-p-98596-1.html?backcPathco=16&cPath=26_11792.

But my mechanic said it won't do any good for a 4 stroke scooter.

Please help, what should I do. I am desperate.
Thanks,
Cristian.

[c.stroe]

Please, can anyone tell me what to do? A sports air filter would do any good for a 4 stroke engine?

And, if yes, what roller should I put into the variator to decrease the revving and maybe increase the top speed a bit?

[Stig / Major Tom]

Cristian, we do not know what country you are in, or if you are limited to a 50cc scooter for some reason.
Getting speed and reliability is, it seems, a crap shoot when you begin modding these little engines.
Yours ran good for a time....now is giving you problems again.
This must be frustrating.
Would it be possible to shop for a used bone stock 125cc scooter to me your needs and finances?
Save you a heap of agro!
Stig