View Full Version : tweaking a 49cc single cylinder 2 stroke air cooling engine on a scooter pocketBike?

09-05-2004, 11:52 AM
i just went to pep boys to buy a mini bike so i talk to this guy about the last one he had there and he said it goes about 30 mph so i tired it and it does pretty good but he had told me a guy there at pep boys has the same one with the same motor in it but he had tweaked his own and now it goes about 50mph....anyways that what i want to do with my engine but dont know where to start does anyone know of any information on this or of any sites that has this info thanks for any help.


09-05-2004, 01:51 PM
Here's a thought...

You already said your local Pep Boys has an employee that modified this same motor, so why not begin with asking them?

09-05-2004, 10:40 PM
Google (http://www.google.com) also would be a good place to start.

09-05-2004, 11:10 PM
You can just change the drive sprockets for higher speed though it won't pull as well but getting the engine ported and polished plus a bit more compression will certainly give it some go.

RP Racing
09-11-2004, 12:27 PM
Are you sure you are willing to trust one of those cheaply built things over 30mph? Guy on a local sportbike board I'm on had the front brake caliper bracket SNAP just trying to slow down on one of those $300 pep boy/cags. Lucky for him he wasnt going that fast and just got scrapes.

12-09-2004, 09:45 AM
2 stroke motors like the one on your bike would benifit greatly from added compression(mill the head).

Also, you should find 2 screws on the carb, one for the low end and the other for the high. You can get higher speeds by leaning the top end, just make sure you dont lean it too much as it could lock your motor up. I would turn it no more than 1/4 turns and do a test run. This alone would probably give you the extra speed you want. Just make sure the exhaust always has a visible stream of smoke, you should be OK.

You could swap a sprocket, but you'll trade acceleration for top end speed.