the not so mini dirtbike

[spinakerjones]

well after working on my go kart for the past week i thought i would switch it up a little by starting a motorcycle project.
i found my old bike i made about 4 years ago here's a pic. i know some work has to be done to fit the engine in im going to mod the body so the engine fits below the seat.

http://i285.photobucket.com/albums/ll77/spinakerjones/IMG_0866.jpg

and im thinking of fitting a street legal engine on it 50cc (in Massachusetts anything 50cc and below is street legal no need for a license) i have a 49cc gas scooter in my garage but my dad doesn't want me to scrap that just yet who knows maybe he wont notice. im thinking of a simple cent clutch and chain #35 drive system don't need anything heavy duty. how fast do you think i could get going? i weigh bout 135. bikes pretty light.

 

[2or3wheels]

ive rode my frinds pocket bike and it gets me going 25 and im 240 pounds.

 

[crazycart]

I made a chopper bike once too. My rake is a bit more extreme though lol!

 

[Kenny_McCormic]

Most of those 50cc engines have tiny output shafts with clutches that use #25 or 8mm chain.

 

[sayre315]

#25 would still work
thats what they use on those razor pocket rockets

 

[spinakerjones]

sorry for the long delay i went sailing for three days. a couple questions, 1. is #25 chain the same size as bike chain? 2. i found a snow blower engine 11 horsepower but it only displaces 21.82cc what is up with this how dose an 11 hp engine only displace 21cc? will there be torque? how fast will it go?
http://www.northerntool.com/webapp/wcs/stores/servlet/product2_6970_399_399

btw nice bike

 

[Kenny_McCormic]

Its 21.82 cubic inches, typo.

 

[spinakerjones]

oh sorry i guess i didn't see that. how many cc is 21ci?

 

[ed1380]

344cc

 

[newrider3]

Bike chain is #41. That frame looks scary even without a motor, I'd suspect you'll crack it easily at one of the welds on the downtube.

 

[847]

but how is the thickness of the chain? example mountain bike chains are thinner so they can shift smoother. i was thinking of throwing a 2 cycle on the back of my mountain bike with a rack. and using the gears to my advantage. will 41 be the right pitch? isn't it too wide for a bike chain? not trying to put it off the original topic ... don't shoot.

edit -

will the bike chain even fit on a # 41/40 clutch, since the chain is not as wide as the sprocket ( or is it the same width? )

 

[Kenny_McCormic]

bike chain is 4 pitch but not width.

 

[847]

you think i could get lucky and grind the gears on the clutch a lil with a grinder? i have a micrometer around here somewhere, how wide should i grind the teeth to?