Gy6 NCY scooter big bore kit vs Chinese brand scooter / moped big bore kit for the qmb139

Rolling wrench shows you the scooter big bore kit they use on all there customer scooters. Should you buy a big bore kit for your chinese scooter? Yes if you want more power out of your 49cc . 50cc scooter

Click here to purchase:

$330 to come to my house to install that. What a steal. I’d take that in a heart beat, if I was living in Denver. 😊💪👊

[RollingWrench]

Yes just pull of the old cylinder and install the new one. everything fits perfect. However I would recommend the 80cc kit on our web site. Its a better bank for your buck.

[RollingWrench]

Scootertuner1000, yes we do have cams as well. In colorado (5280 feet) after installing a standard 80cc kit no other upgrades we don not rejet.

[piperpilot]

Damn, I wish there were services like this in CT. I'd love to get an upgrade like this. $330 installed? that's crazy! I'd be more than willing to pay that price.

[jgilk]

Stock crankshaft the 52mm head is ~88cc and the 50mm head is ~81cc

If you combine with the full circle stroker crank 44mm vs 41mm you get 93 and 86cc


For best performance of the 52mm head should be paired with a higher lift can bigger valves and a larger tapered bore carburetor... Good for about 10hp? Ish

[RollingWrench]

Peter,

We have had major issues with the 10cc kits. (They bearly start, smoke, and kill the crank bearings) There is not much of a difference between the two as far as power. We wnt through tons of 80cc kits to find the once that work the way they are suppose to. The ncy are good but you still will kill the crank bearings and electric start struggles.

[rbarbour]

Good price to put it in.
The place I got my scooter from wanted to charge me $450 plus just to replace the rings.
I was thinking he would give me a deal sence he overcharged me on the scooter($1800.00) new. I  also bought a used 4 wheeler($2500.00) at the same time.
I trusted a local man that will never happen again.
Less than a year and half the motor locked up.
Did not see no oil leak at all.
Sounds like you have a fair price on your work. To bad you are not in NC, Could use a good repair shop on scooters.

[michaelhightower]

🤔 Now you said the 93cc is a 52mm .So what is the 80cc measurement ? Because you didn't tell us this in is video.And keep these great information video of your coming here on YouTube 🏆🥇🙏🤗👍!

[sqrl]

i have a kymco people S with that 90cc ncy cylinder kit (with valve head ) and it electro- starts great.
only problem is that after +- 4000 km the magnet breaks of the crankshaft
this has happened 2 times already with the original crankshaft, now i got a naraku.
i think that 80cc is really the limit for that engine, my bro has drivin 42000 km with a 80 cc without any problem.

[RollingWrench]

yes anytime you do a performance upgrade you are going to jeopardize the rest of the engine. They 80CC is very reliable

[michaelhightower]

🤔Now can you just unplug a DC CDI and just plug in a AC CDI ?Or is it way more to it to make this kind of change?

[Camaro]

When you have installed the 50mm or the 52mm big bore kits how many connecting rod failures have you had? I find that after installing over a 47mm big bore kit I have had connecting rod failures but not all of them. Is there a Taiwan crankshaft that is same as the stock but with better bearings without using a stroker crank?

[NoReverse]

Wish I still lived in Colorado. I need some parts. Ebay it is haha

[jimambonekeener]

I got a 100cc kit but it’s 50mm and it didn’t come with head/ valves will my stock one work engine is a 1p39qmb and the kit is for the engine but I don’t know if stock head will work?

[daand]

50mm=85cc and 52mm=90cc, and not 93cc.

Going to install a 80cc in mine this week.

[redneckhippiefreak]

Piston is NOT  Billet Aluminum. They are cast and machined or forged..Probably cast seeing as how you can see the casting marks on the underside.0:37

[chairboygazza]

is there any re tuning to be done after the kit has been installed do you have to change the exhaust and how much speed are you likly to get out of this conversion

[petersabino]

Well Like you said im having trouble starting after the 100cc big bore kit, i tryed realigning the cam, adjusting the valves, and ignition coil, also spark plug, now i think its just the electric start thats not enough to crank it ove. My scooter doesnt have a kick start. do you think the kick start would make a differrence and if so can you cutt me a deal on one for a gy6 50cc taotao. i also need the from belt cover because theres a big hole where the previous owners took the old kick start out

[owenridener]

I've been having trouble installing big bore kits in older gy6 50cc like 2006 and 07 engines what happens is the timing chain appears to be to short any ideas

[ezurmnd]

So would you recommend a high torque starter?