gy6 50cc big bore 50mm top sped
 

I have ben work on the 1p39qmb (gy6 50cc) engine try to see hp gains and top speed and it getting there. the video I have here is before the new variator and 150cc intake and 24mm carburetor I still had stock variator and stock intake with 22mm carburetor on in video. new carburetor still not here yet and debating on getting one of the performance Drive Face for less wheat.






https://www.youtube.com/watch?v=wpgzlqfQN5I

I don't post much on scooter forums, but I've been riding my scooter for almost 6 years now. Your upgrades are impressive, but your driving is scary. I recommend you take a motorcycle course before you do much more riding. Be careful out there!

well I made the port to big for stock intake valve. I got it to tune for best and it was good mid rang a dog top end. best port size for stock valve 20mm or 22mm I was letting to much air in for a small valve. I mite try the big valve head and it should work for the port size that I did have.

now going back to stock intake but port it a bit and a bigger jet 105 or 108.

Cool and seems very quick. But you may want to stop looking at the speedometer so much. You almost hit that Pontiac in the rear end twice.

Bigger Carb....bigger Jet and bigger 150 Intake Manifold will not equal more speed and power.. A stock engine is only 50cc(3.05 cubic inches) and even a true 80cc BBK stroked is(4.63 cubic inches) Therefore the most fuel/air you will EVER be able to draw into that engine per stroke is..50cc-80cc(3.05-4.63 cubic inches) Think about older car engines..they were 305-460 cubic inches for the Ford series anyway...and they could have a bigger Holley carb on them for extra power. But on a tiny engine like ours...it would take exactly 100 Scooter engines to equal 305 cubic inches.(same as the 5.0L engine) For more power you need ..more rpms..more displacement...Nitrous Oxide..Nitromethane based fuel.. All of which will grenade your engine. A 24mm carb and 150 intake are overkill and will not do it...the engine simply CANNOT draw in that much air/fuel. Therefore I would opt for the 'Road Runner' cartoons ACME Jet Pack..
:hmm:

Well on my way to work today after jet changes and a bit of tuning and adding the rpm gauge SHE IS FASTER IN TOP END!! They say on some forums that 50+ is a bit more then 7200 rpm HA.... i win.......

Yup..you win. All the Pro's here that build them to race and have been building the GY6 50 engine for years..cannot beat that. 7,200 rpm at 50+ mph is good..I can't even come close. But..if your Speedo shows it..it has to be right. Did you get a vid of your Speedo readings on your cell phone cam? We would like to see the results. Way to go and congrats!! If that was only 7,200 then redline at 8,000 should get you close to 55? Or in that ballpark anyway..:tup:

what about if i have a bad tire. 8,300 rpm

A bad tire? Not sure what you mean. Like it was flat? Confused.That should not make it go fast. Or are you saying it would take 8,300 rpm if the tire was soft? Sum it up if ya would and tell us what you did to hit 50+ mph with a stock 50cc Scooter. We would like to do that too ya know, so no secrets allowed?:shrug:

Big bore 50mm in title

well stock clutch I think cant hold the power a bit in mid rang and a lot more at top end it pulls and then stop pulling and then starts pulling again. like a light switch going on and off

Well still same set up with 22mm carb didnt jump to the 24mm carb yet. 102 or 103 drilled jet im using on this. Just got new top speed and still stock gearing 61 MPH yes 61 MPH video shows 60 but it hit 61. Video and pic will be up some time soon

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