Agility 50 Big bore kit

[baddi]

Yep, the gearing of the kickstarter and starter motor are calculated for a 50cc. With a piston surface of about 1.5 times as large as that of the 50cc, their job is a lot harder with a BBK, even while the compression ratio itself is still about the same...

I never use the kickstarter because my electric starter always works, but often the starter motor stops at TDC and I have to release the starter button and press it again to get it through the compression stroke.

This annoyed me at first and I was scared that I might burn the starter motor, but nowadays I hardly notice it anymore - I just release and press the starter button a second time if needed, without thinking...

Something on the scooter made specially for 50cc? Thats a new one.
The agility 50 was originally sold in taiwan with an 80cc cylinder, but are as all other scooters fitted with a 50cc cylinder to be sold on western markets.
This is why the counter spring are so tight on the agility compared to many other scooters and also why the original exhaust has been modified to a smaller diameter (to keep the air speed right, to create negative pressure behind the initial pressure wave, which helps fully empty the engine).

I know that the kickstarter sucks on our little scooter, but that may be more of a design flaw from the engineers, as changing this would mean a redesign of the whole kickstarter assembly and variator shield, which would not only be very expensive, but unneccersary from the eyes of the producer, as they don't want us to temper with the motor or change anything on the bike to non-kymco parts.

[mono]

@baddi :

The agility 50 was originally sold in taiwan with an 80cc cylinder, but are as all other scooters fitted with a 50cc cylinder to be sold on western markets.

I've heard such stories before. The most common version I heard says that the engine was designed for 50cc but later modified by Kymco to be also sold as a 70cc or 80cc model..  Can you tell me where you've got this information from ?

I'd like to know wether one of these stories is true, since that would tell a lot about the durability of an "upgraded" engine, but never found any reliable source to confirm them... Maybe Google hides Taiwanese sites from my browser ?

@scooterman11 :

She ran for a while but only with a fight trying to get it running it was spitting out through the carb like it was flooding, but still will not idle on her own

Since you can tell it was spitting through the carb, were you starting the engine with an open carb without airbox or airfilter ?
If that's the case, then you should try it again with airbox and/or airfilter in place - without filter it will definately run very lean, which can be a valid explanation for hard starting and spitting...

Another possibility is that your cam chain is one tooth off from the correct position, which would certainly cause hard starting and could also cause spitting - when it's not far-off enough to make your valves collide with the piston, that is...

[baddi]

@baddi :
I've heard such stories before. The most common version I heard says that the engine was designed for 50cc but later modified by Kymco to be also sold as a 70cc or 80cc model..  Can you tell me where you've got this information from ?

I'd like to know wether one of these stories is true, since that would tell a lot about the durability of an "upgraded" engine, but never found any reliable source to confirm them... Maybe Google hides Taiwanese sites from my browser ?

[..]

My information about this comes from the most enthusiastic and most clever kymco driver i have ever known. He is a great source for much of my knowlage about this bike and the general engineering of scooters. He was a great man, and have often been refered to as the encyclopedia of "billig-scooter.dk", but unfortunately he passed away, died from a stroke while parking his kymco super 8 125cc a couple months ago and i forgot to ask him where he knew this from. 

About google: google can only see 90% of the visible internet and the visible internet is less than 5% of the whole internet. Since this is still incredibly many sites, google filter the results according to what you search for the most, where in the world you live, what others in your country search for the most and your language, among other less important search factors. This way, i have yet to discover a Taiwaneese kymco site, which are not publicity for the western world, and therefore i don't know what kind of scooters are currently sold by kymco in Taiwan. :p
Trust me: i have searched for ages on several search engines to find this, but unfortunately i dont know Taiwaneese or their alfabet, so i cant find any Taiwaneese search engines, as these would possibly give a better chance of finding the original kymco site.

One of the things that backs up my suspection is that the motor is labeled LDC6, but that many of the parts are have LDC8 in their part no. as if they were made for another engine. I dont know if the LDC8 is the 125 model, which agility 50 shares alot of parts with, or if it is the legendary 80cc engine, but the search continues.

[scooterman11]

i drilled out one of my spare 35mm pilot jets with a 1/32 drill bit is that too big for a 70cc big bore kit, i tried starting her and she popped like she wanted to run
thats more than i get before

[mono]

@scooterman :

I'm starting to think that you're just trying out a lot of random things that you've heard some people say somewhere without having a solid grasp on the concepts of which thing does what...

Am I correct ?

It really helps if you tell us exactly what you have been doing step by step and tell us exactly what observations you make... First you tell us that your scoot ran for a while, and now you tell us that almost starting is more than it did before... Am I the only one that's confused by this ?

[mono]

@Baddi :

I just found that the engine on the Kymco Mongoose 50cc and 70cc ATVs both seem to be a GY6-50-like engine. (http://www.stadiumyamaha.com has some drawings weird enough)  Some important parts like valves and valve rockers have exactly the same part numbers in both the 50 and 70cc version, but other parts differ... The difference between the two crankcases etc. looks a lot like with the short case / long case engines of my Agility 10" and 12" versions...

Too bad that the Kymco parts were removed from the Easyparts site, I could have done a quick crosscheck with their part numbers for both the Agility 10" and 12" to confirm whether the 70cc ATV engine is really basically the same as the 50cc GY6 version engine for their 12" scooters.. I will need some more time now...

So Kymco does seem to build 70cc versions of the "GY6 50cc" engine indeed .... ?
Slowly closing in on the truth (or myth) ?  


BTW, don't you just love a forum where drifting off-topic is just normal 

[baddi]

@Baddi :

[..]

BTW, don't you just love a forum where drifting off-topic is just normal 

No, but for some reason i have been doing it alot lately myself 
Must be beacuse its summer and i'm not in school

[scooterman11]

I am confused too srry guys for going back and fourth