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Cant do what Honda did.
They used a fully custom 50cc twin cylinder 4 stroke that would hit 20k RPM to get their 20hp.

On a 2 stroke 50 it's much more doable. Since, it's effectively displacing twice as much at the same RPM as a 50cc 4 stroke.

I think displacement shouldn't be looked at by it self to say if something is possible or not.

Comparitive power of engines should be looked  at with a combination of stable max RPM, power stroke count, and displacement per powerstroke- multiplied over a period of time.

The 300i may displace way more in each power stroke, but it has half the amount of power strokes, and does it at a lower rpm. So the effective total amount displaced over minute isnt as high as say a high revving 120cc two stroke.

Had to do modifications. There is no more starter at 115mm. Kickstart forever, or a drill.

The belt in the pic hasn't had the engine started/isn't tensioned.

Also swapped variator parts to let the belt ride further inward in the rear.






Had taken measurements and done the math for the belt size. Closest, within a few mm, is a Gates PL30302 belt. Is 757mm, from the wanted 755mm, up from the stock 743(? 745?) This is the size with the mod to let the belt ride in further. Without it a even larger belt would be needed, that, is a size is not made from what I can tell. "First Belt" makes a 777 16.5 30 which seems to work, but the short belt teeth mean you'll need your CVT ramp angle and spacing perfectly adjusted to not flip it.

All this should let the belt ride up to 113mm out of the 115mm. That's important though, as the variator face tops out at 113mm. This is up from the stock 85mm, combined with riding another few mm inward on the torque pulley, making the theoretical gearing limit 60mph.  Downside is the GY6 150 weights bottom out at 6 grams. Requiring a aftermarket bore to handle the rate it gears up at.

Next is to put a zuma minarelli horizontal bore on it (fits stock), and to modify a exhaust from one to tilt up 15° to compensate for that tilt on the Kymco bore direction. A 2Fast cylinder anyone? 20+hp and liquid cooling here we come.

Have had it installed, and running for a few weeks.

Works! Sorta.

It drops a lot of compression since it's shorter, and I mean, a lot of compression. Before I started using it daily, I took a zuma2t head and ground it down a fair bit to raise the compression back up some. Still not as high as it should ideally be, but is loads better.

Power wise, it feels the same as a well tuned stock bore. Likes 9 gram weights the best, but stuck 10's in it for the break in.

Has been solid. Been using it as my daily, and have put over 300 miles on it. Again, could use more compression since I'm still shoving 93 through it, but, is stable.

However- have dropped the whole engine/arm now. Is getting swapped with a 100% stock engine to scoot around on...while this one gets rebuilt with aftermarket form the ground up. Only stock thing left of it should be final drive- fun.

Important thing learned here-

Do the cheap china pistons work?
Yes
....but sand your head down to get usable compression.

So. Took the Polini kit. Did a lot of lye baths, rotary work, grinder work, 1200 grit sanding, a cheap replacement piston, and desperate feelings for it being down for two week while a new stock piston comes in ( is at 8k miles-ish, so, time for a new piston).....and my Aprilia's back tire going flat.

It works now! Not sure how long this'll last, but, it works. Will throw the 13 weights on for the break in once they come in. Force the RPM low, since I'm pretty sure the crank is damaged from me pegging the speedo past the "Km/r" mark on stock gearing/tire size, or maybe forcing the cylinder to fit when it shouldn't have, or having used a impact wrench to take the variator off since I couldn't get a good grip anywhere on it with my face wrench.

Ordered the Malossi cylinder kit as well, but I'm not installing it until I buy the Jasil crank, and do a rebuild of the case- or have someone else rebuild the case cause I hate doing it. As, doesn't matter what methods I employ- always loose a screw or other piece if its not done in one sitting. 

I am entirely sure this kit is either only meant for the Dio engines, or I was sent a Dio bore by mistake. Polini uses generic boxes between most their cylinders, and leave no identification markings on the bore to indicate what it's for. It has the same diameter of a 70cc zuma minarelli bore, which, doesn't fit the common People 50 2t, but retains the exhaust for a dio/kymco. Could also have shaved a zuma 50 cylinder skirt to fit, but I don't have the tools to do that accurately.

Back on topic- reviving and modifying it worked. The cylinder I got is obviously not meant for the common US people 50 2t, and until you yourself have tried it, don't assume it does based off a spec sheet. If you do get and try one on a US people 50- let me know how that goes. It'd let me know if I got sent Dio cylinder, or if it doesn't period.

annddd

http://www.epfguzzi.com/kymcobiz/accessories/index.html

There ya go. Have one on mine and can confirm that's exactly what it looks like. The rear 3 "mount" holes don't bolt into anything, and are there for adding on a trunk. If you want it to look "sleeker" you can cut them off without losing functionality.

It doesn't actually match color wise . Gets close though. 

First thing I'd want to know is why did it seize in the first place. 

never seized. piston was off center slightly, ground/melted all over one of the walls till it lost compression.

off topic though

Not important rightnow. All  possible isues were adressed in another post.

 This is seeing what a jank piston will do in nice cylinder instead of buying the $$$ polini one that costs half the price of the kit.

Huh, didn't notify me of the post. Came back after idly looking at the cylinder, noticing something very nice.

 The apparent gouging near the exhaust port? Turns out, not actually gouging. That's all material from the piston. Ground off the piston, and apparently, melted onto the wall. Picked at it with my nails a bit, and a few pieces on the edge just flaked/chiped off like they had melted on top of the beginning of the cure, and not into the cylinder! Might still be gouged a bit underneath it all, but, for the most part, seems like I should be able to recover the cylinder with minor damage. Damage minor enough, that I hope a solid cure layer can compensate for it. (Got hot enough to make the piston melt instead of destroying the iron XD my luck 10/10)

Was going to send it off to a machine shop to be re-honed, but might do it myself if the one-use honing tools are any good...given they're like 15$ vs probably at least 50$ for a machine shop.

ALRIGHT BACK ON TOPIC

Cork Gasket: Yep, made one for the base, and is why I went with the brown paper for the head gasket. Tried to sand down the head a bit with some paint graded 600 wet grit to compensate, but, it didn't seem to make any progress on the aluminum. The cork compresses quite a bit anyways, so whatever difference it would add to thickness, wouldn't be much. If anything using the paper on the head with the cork at the base would've raised my ports a bit for more power, but, again, is/was minuet. Reason? cork sheet/roll I can cut to any size gasket on demand- get 6 feet for 10$. A new specific use gasket I have to wait 2 days to a week, or even two weeks to receive?- varies, but lets say at least 3$. By the time you've bought 3 of them, you could've just bought a roll, made 30, and have gotten a fitted gasket in under 30 minutes (I put on some netflix and take my sweet time OCD measuring and cutting one though x3)

Carb: I got the bike 3rd hand from a ex kymco dealer. I guess they had it in the shop when the owner moved to another state or somthing, or they didn't want to pay the repair and just ignored it before moving? I duno, but apparently one of their guys had been messing around on it it bit, and I noticed one or two minor non-stock parts on it. They could've changed it out before it was sold to me. Oh, btw, this guy had a huge storage locker filled with kymco bikes, kymco stock parts, kymco performance aftermarket, and who knows what else. He had a super 9 in the back apparently (thing was so crammed full you couldn't step in) ,and I should've asked if he'd sell me that instead, but oh well. Still have his number, might be on the forum if he has that much stuff.

Even with a 120 jet, the top end seems to run lean. Don't know why. If I richen the idle, let it sit and fill the case a bit before taking off- my acceleration will be way better. Been playing around with needle size. Oh, stock needle on it isn't adjustable, same as the Roughhouse. Didn't stop me from modding the needle mount to take regular ones though. Will see how that goes later. Im going to give in one day and by a electron pumper carb to make jetting easier. 

Oil: Haven't run straight raw castor oil (yes the bean oil). I use Maxima Castor927, as, it's the easiest to get modern equivalent of it, and they apparently add in things to deter some of the sludge build up that castor oil usually makes. https://www.amazon.com/gp/product/B000GZV25G/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
Is pre-mix only, as, it'd clog a auto mixer, and is more sensitive to being at a set mix as opposed to a varying mix like most synthetics. Since it is thicker, and leaves more/quicker build up- it's a bit of a cheat for break ins if you want to push the cylinder a bit more during that time. Could probably do a endurance race on a brand new cylinder using it without destroying the cylinder, but, the cure would be awful. Also reportedly adds a few hundred RPM too, but, eh, I'll just call that good curing vs ok curing. If someone went out of their way to buy castor oil- then I'm sure they'd spend the time to do a good break in too.


Plug: The 7 is a little hotter, but it's also one that's more immune to high heat in general. So high heat resistant+foul resistant I think is a trade off for running the whole thing a notch hotter. Plus, and I know it's wrong compare them, but, the morini and yamaha minarelli 2 strokes, as well as tons of others, usually use 7's. An 8 or 9 may be better for this, but, it shouldn't hurt it to be outside spec by 1 when using platiniums like that.  Oh, burnt out/semi-melted a E3 in it. Was carbon build up on the melted bits too. So not like it was lean. Guess their plugs aren't actually rated for what they say they are! (generically claim, I think, 6,7,and 8 heat rating, and say they're better at dealing with carbon build up) Haven't burnt out a NGK in it yet though. Have gone through a few new ones to troubleshoot,but never a failure as of yet. I have a 2 stroke specific 3/4" NGK spark plug for 2 stroke racing I'll throw in at some point once it's all dialed in for the 70cc bore (BR9EG).

Case Gouge: actually have no idea. Was partialy like that when I first opened it up. The Polini may have added a bit, but, yeah most those were already there surprisingly.

Crank: Really? I mean I'd be throwing 8k-9k at it the entire time to stay in the peak for the TT. Hmmm, though not sure of the condition mine is in either, and an OEM replacment costs more then getting the Jasil one. NO idea what the Jasil crank is stable up to. Can't find user info on it anywhere.

Kit: Buying a replacement piston meant specifically for that kit, is pricey. Buying one of the same size? With sh/h, 20$. It's not the exact same piston, and performance might suffer a hair, but it'll work, and doesn't cost half the price of a new cylinder. The one I got seems like it'll make a hair less compression, but I can always lower the head height for that (there's a decent chunk of the heads height that's not the compression area), as heads are cheap too.

Leak Down: Nope! Which is bad. That said, all the gaskets I've made, and have looked back at after use, haven't had any signs of leakage from them thus far. I do use a torque wrench though on anything with a gasket, since I don't trust my "feel" for that.

MISC:I have a analog torque wrench, but- On most parts of bikes I use a low-powered 3/8th impact wrench (what?)- I use a corded "matrix system" (every company calls it somthing else) base "gun", and slap on the impact wrench geared end for most any bolts. Can take off the CVT cover in under 30 secs, and slap it back on in the same amount of time. Seat is off in all of 10 secs. Extenders and adapters let me get to most things.  The amount of time I've saved on it 0_o  Helps with stuck spark plugs too (carbon/caked-n-baked oil in threads). Makes me feel like a Nascar pit stop x3

chamfering the ports-
Didn't need to. Polini seems to do that for you as apart of their production process. If you don't believe me, I have another new in box Polini cylinder (for a zuma 2t) I could take pictures of. 10/10 looks NICE.
The Arisal I got for my 03 Aprilia also had this done from the looks of it. The Stage6 I had didn't. It's a hit and miss, and alot of people say you shouldn't need to do it, and that the rings will cut them as apart of the break in process.
Not to say it isn't necessary sometimes, but unless it's horrid, lot of people say you don't need to if you break it in properly.

Rust? What are you-
Ohhh that's copper gasket spray. I cut a cork gasket to shape, and sprayed both sides of that to help prevent it from leaking any. The head gasket was, quite literally, brown paper bag, coated in gasket spray.
When opened up- neither had showed any signs of having leaked. Worked 10/10.

The carb-
Kymco made a few variants/revisions of the People 50 for the US. The earlier the model, the less restrictions there seem to be. The newer it is, the more emissions regulations there were in place making them limit it in more ways.
You can get a stock 17.5mm people 50 carb. It's rare, but possible. Mine may have not come with it, but the one that was on there when I got it was a stock brand matching carb. So either someone spent 100$+ on a carb for it, or it came with it. Mine is a 05 production model.

Castor oil doesn't burn completely, and seeps into everything. If you run castor oil- you'll find the outside of your engine coated in the stuff. It gives everything a sticky yellow looking tint, which most people think is bad, nasty, ugly, and bad- but in reality it'll protect various parts from corrosion and oxidization.

I was running castor oil for my pre-mix at somewhere between 1/35 and 1/40 (human error and all). Normally I run yamaha lube (one of their dealers is 1 mile from where I work), but use the castor oil for break ins.

The plug is a B7EVX. So, a heat range of 7, and is platinum. Before you ask- yes the Polini head uses a 3/4" plug length.

Engine ran 10/10 before I stuck in the cylinder. Runs fine after too now that it's back on the stock cylinder.

The "gouging"-
You didn't look at all the pictures? Should be obvious what caused that.



See that huge chunk missing from the piston. Yeah, that piece broke off, but stayed pinned between the piston and the cylinder, scrapping up and down with each stroke. It did not fall into the casing. Only fell out once I removed the cylinder from around it. Have the missing chunk, somewhere, prob lost it by now, but yeah that's what did a lot of the damage I'd imagine. The other half being done by the slammed/pinned side of the piston that got its ring melded into the piston.

I'm going to try to have the cylinder re-honed, and have already ground down the base of the skirt that had no cylinder wall on it (bout a 1/8th an inch, maybe more). Ordered a off-brand replacement piston with no piston ports just like the Polini one that came with it (has a bit less height, but can always lower the head to compensate for that). I'm, pretttyyy sure the issue was that the skirt was too long. Since it's at the last 1/8th inch or so that the cylinder was being difficult.
What else.....yeah Ima probably throw the bikes crank soon with the amount of RPMs I'm throwing at it. I'm right at the edge of stable, but oh boy does the TT exhaust love to give more power when given more RPMs. Can't wait to throw it to the wall when I get in some new taller tires. Aiming for **actual** 60mph stock 50cc bore. Already can do a real 50 (spedo reads, 55 or somthing higher, is blank by that point).

*police officer pulls me over*
"Do you have any idea how fast you were going. I pegged you going 60 in a 45"
Officer, not to be rude, but this bike only has 50ccs. Are you sure your gun was dialed in correctly this morning?

I don't think it'll get me out of a ticket, but, in brightest of fantasies it gets me out of a ticket on the pure absurdness of it. Can't wait to push my people 50 more <3