2 stroke 49cc speed question

[aboudie19]

Hey,
I'm 5'8" 170lbs and I have a 49cc dirt bike I bought from Belmonte Bikes. When I first got it it was reaching a max speed of 22mph, but then I did some research and I added a Big Bore Kit 44mm for my bike. It's added about 5hp extra to my bike! Definitely feels faster than it was before but havent tested the exact speed yet. It's at least 3-5mph faster though.

I bought the big bore kit for $59 from here:

https://www.belmontebikes.com/produ...2-stroke-47cc-49cc-engine?variant=24580696129

And I bought my 49cc Dirt Bike from the same website in case it matters:

https://www.belmontebikes.com/colle...um-gas-dirt-bike-2-stroke?variant=25532026945

 

[Steve Best]

Hey,
I'm 5'8" 170lbs and I have a 49cc dirt bike I bought from Belmonte Bikes. When I first got it it was reaching a max speed of 22mph, but then I did some research and I added a Big Bore Kit 44mm for my bike. It's added about 5hp extra to my bike! Definitely feels faster than it was before but havent tested the exact speed yet. It's at least 3-5mph faster though.

I bought the big bore kit for $59 from here:

https://www.belmontebikes.com/produ...2-stroke-47cc-49cc-engine?variant=24580696129

And I bought my 49cc Dirt Bike from the same website in case it matters:

https://www.belmontebikes.com/colle...um-gas-dirt-bike-2-stroke?variant=25532026945

Hey Aboudie19, can you get me an accurate measurement from bolt to bolt across your head or cylinder?
Here are the measurements I am looking for:

Can you find these measurements?

 

[skyash]

I got a 44mmbigbore and its not the same but it measuresthe same and i get 50mm where the ? Is

 

[zippinaround]

that big bore kit is for a mini moto engine , you have a mini moto eng on your bike?

 

[skyash]

Yeah a pocket bike motor with a big bore kit installed on my push bike

 

[zippinaround]

nice any pics?

 

[skyash]

Its a 26inc bike with 20inc forks and wheels . Welded the seat post on the frame .pedals off a kids bike i made the tank made some clip on handle bars got a 52t sprocket lazer cut after having a 54t made up frist made a spacer for the forks to fit on welded a metal plate mount up welded a drive sprocket from a 66cc on the shaft of the pocket bike transfer box i use a 415 chain. ..after the frame broke in 2 places on the weekend i have started covering the frame with sheet metal and re welding everything. I all so made a new head for the engine you can see in the pics .the stock motor 2hp did 45kmh no problem the big bore 4hp one hits 60kmh no problem straight out the box played with it a little new carby spark plug and rocket key now gets 67kmh.. so i wood like a 50t sprocket. I just lightened the fly wheel opened the boost ports and transfer ports took a little off the top of the exhaust port.just need to finish the frame and put it back together. Then see what i hit.

 

[zippinaround]

Looks cool im planning on making a full suspension with rack mounted mini moto engine , the one i have is stock but can get a brand new racing engine for about 90€ brand new compared to about 60€ for the big bore kit that includes a racing crank, can get the one without crank for about 35€ .

Anyway i need to make my rack next but am gonna try using the normal chain 25h probably a bad idea really haha

 

[Ely]

Hey i am 11 years old 80 pounds and i have a 49cc pocket bike and i need to know how fast the can go all stock because i have a race in a week

 

[Steve Best]

Hey i am 11 years old 80 pounds and i have a 49cc pocket bike and i need to know how fast the can go all stock because i have a race in a week

This is a complicated answer Ely.
First off we don't know the type of bike, engine or gearing, so impossible for us to answer top speed or acceleration.
Secondly, we don't know what sort of race, so we cannot advise on how to tune for it.