best-worse 50cc bore kits

[tiba_karotsu]

dude you are making too much of a fuss over this kit selection thing you'll be wasting more money if you go with a 50cc kit & unless you tune it properly you won't gain very much in terms of power, if you ride like an @ss on the street then not even a stock scooter can prevent you from crashing.

we have full race 70cc set ups that are being ridden on the streets, just as long as you ride with a level head & use good judgment you'll be fine, your streets are nowhere near as safe as ours, try riding here for a day & see if you can survive.

 

[muhuha]

sod buying a kit then, im not a bad driver quite aware and dont do stupid stunts. i'm going to port the standard for the time being, could someone tell me what i can do, the book doesnt tell me measurements on my cylinder. When i had my cylinder head off i noticed the piston stroke was stopping wey before the top of the barrel, will the squish increase if i file down the top of the barrel so the piston gets closer to the head? Could you also give me a idea what i can do with the exhaust port.
Cheers!

Will be getting a corsa soon, got to buy a helmet due to some idiots punching me and trying to nick my ped.

 

[tiba_karotsu]

sod buying a kit then, im not a bad driver quite aware and dont do stupid stunts. i'm going to port the standard for the time being, could someone tell me what i can do, the book doesnt tell me measurements on my cylinder. When i had my cylinder head off i noticed the piston stroke was stopping wey before the top of the barrel, will the squish increase if i file down the top of the barrel so the piston gets closer to the head? Could you also give me a idea what i can do with the exhaust port.
Cheers!

Will be getting a corsa soon, got to buy a helmet due to some idiots punching me and trying to nick my ped.

get the MHR Replica, rotax exhaust port & nikasil plated aluminum kit, trust me you'll be much happier for a few $ more.

you can mill the deck of the cilinder to close up the squish clearance to the head to increase compression & power but mill too much & the piston might contact the cilinder head causing damage, i won't bother milling the deck but porting the cilinder can net a couple of hp if done correctly.

the book only teaches you the theory & principles of 2T engine & what might happen if you do a certain modification & that's about it, the book is there to point you in the right direction & your task is to apply what you have learned & reap the benefits if done correctly.

 

[muhuha]

right im going to takes 2-3mm off it obviously checking as i go. When you say porting you mean all the ports yes? I'm not too sure what i can do with the ports going into the piston but the exhaust port i think i can do something with.

reguarding the exhaust port when the piston is at its lowest point is that where the bottom of the exhaust port should be? What bout the top should i just leave that? and reguarding the width how wide can i go.

 

[tiba_karotsu]

right im going to takes 2-3mm off it obviously checking as i go. When you say porting you mean all the ports yes? I'm not too sure what i can do with the ports going into the piston but the exhaust port i think i can do something with.

reguarding the exhaust port when the piston is at its lowest point is that where the bottom of the exhaust port should be? What bout the top should i just leave that? and reguarding the width how wide can i go.

just add enough gaskets under the cilinder so when the piston is at BDC the edge of the piston crown is level with the floor of the ports then take the piston back up to TDC & see how much deck clearance you got, if you want to mill the deck to close up the squish make sure you have a minimum of 1mm deck clearance.

if you have the right tools you can tune all the ports but the transfer ports is best left for pros so just concentrate on the exhaust port for now, just match port the outlet to the pipe's exhaust flange & make sure it goes all the way in stopping short of the bore, just blend it in smoothly.

 

[muhuha]

right reguarding the exhaust port been reading and said i can take between 0.6-1mm off the top and widen by 0.5mm (is this each side of the port?) and seeing as my exhaust port is square and goes onto a round exhaust flange do i leave the port on the cylinder wall square and gradually make it rounder?

^^ is that what you meant?

 

[StepVino]

right reguarding the exhaust port been reading and said i can take between 0.6-1mm off the top and widen by 0.5mm (is this each side of the port?) and seeing as my exhaust port is square and goes onto a round exhaust flange do i leave the port on the cylinder wall square and gradually make it rounder?

^^ is that what you meant?

...The cylinder's exhaust opening, where it attaches to the pipe.
Make it match the size of the exhaust pipe opening. Once the
cylinder's flange is matched, extend that same cross section shape
inwards, towards the inside port, and blend it into the port shape,
without changing the shape of the inside port.

 

[tiba_karotsu]

^^^^^^^ well said step.

 

[McScooterson]

So you when doing that do you open the area of the port that is on the cylinder wall, or just blend the shape of the flange closer to the wall?

 

[muhuha]

i opened the actual port-cylinder a bit then from that shape blend it to the exhaust shape.

 

[McScooterson]

Thanks for clairifying that.

Since this thread is for 50cc's,
I have a Yamaha Vino that I would like a little more out of. I don't want to change the carb, and all the headaches that run along with a fully modded bike(already have one of those). I want to put an aftermarket ALUMINUM 50cc kit on it. The only two I've seen are the Airsal T-6, and the stage6. Any ideas?

 

[muhuha]

i had a stage6 with my pipe (laser x-pro) it was crap had to run super light rollers but when i had heavier rollers and setup okish from 0-20 was quite a bit beta.