100% RPM's grubee skyhawk

otis · #1 03-12-2010, 12:39 AM

hey guys, I have the 48cc Grubee skyhawk,old style carb,i honed out and cleaned up all port manifold and exhaust, but didnt actually touch the ports on the cylider itself,this did nothing it still didnt get full rpm's it sounded like it had a govenor still.so i took the cylinder off and matched up all ports best i could ,took a lot of metal off cylinder por,planed head a bit reassembled and instead of topping at 45kmh the rpm's keep revving to 51kmh/31mph {i have GPS} it vibrates a bit and is a bit too high rpm's for cruising but its awsome that thier tere when u need em, i have stock plugs,caps,wires and carb {except i honed it right out} but am looking to change that,I have lots of torque but want more speed without more rpm's so im gonna gear down from my stock44T to one size smaller around33T maybe anyone know the cheapest place to order from and what kind of gains ill get?? and anone know how to get vids from ps3 onto here or youtube? thanxxxx for helpevwryone i love this forum wicked, happy rippin

bairdco · #2 03-12-2010, 12:58 AM

popular belief is for every tooth you drop you gain 1mph. works on paper, more or less.

plugs and wires you can get cheap from a good auto parts place.

manic mechanic sprockets and adapters are the way to go. try him or pirate cycles, they carry them.

otis · #3 03-12-2010, 01:20 AM

what plug exactly should i get it came with LD Z8C

bairdco · #4 03-12-2010, 01:37 AM

most popular seems to be the NGK B6HS. i run the B7HS, and a lot of people run the B5HS.

you can't go wrong with NGK.

as for plug wire, i buy 7mm copper core wire by the foot, boots and terminals and make my own. it's really simple.

Bikeguy Joe · #5 03-12-2010, 04:18 AM

I wouldn't go down to a 33T, 40T should be about all your engine can haul.

Cabinfever1977 · #6 03-17-2010, 10:33 PM

Wow i didnt do anything to my motor and it goes 32mph already.
I thought about getting a smaller sprocket to gain 3mph, but decided not to cause i dont think it would be worth paying $20+ and i dont have to peddal at all now but u might have to if u get a smaller sprocket.

bairdco · #7 03-17-2010, 10:41 PM

i run a 30t on a 24" bike with a grubee starfire 66cc and it hauls. it also has good torque off the line. part of that is because of the smaller diameter wheels. the other reason is because my motor is the most freakin awesome motor i ever blueprinted...

anyway, despite what Joe's tellin' ya (

) if you have the chance ($) experiment with different sprocket sizes. plus, it'll keep the forum sponsors in business.

melvin313 · #8 12-14-2010, 04:48 AM

i am from puerto rico and we use the ngk br8hs spark plug calibrate to 45 mi bike run 47mph.i have a 47cc engine.

Venice Motor Bikes · #9 12-14-2010, 08:54 AM

Quote:

Originally Posted by Bikeguy Joe

I wouldn't go down to a 33T, 40T should be about all your engine can haul.

Quote:

Originally Posted by bairdco

i run a 30t on a 24" bike with a grubee starfire 66cc and it hauls. it also has good torque off the line. part of that is because of the smaller diameter wheels. the other reason is because my motor is the most freakin awesome motor i ever blueprinted...

anyway, despite what Joe's tellin' ya (

) if you have the chance ($) experiment with different sprocket sizes. plus, it'll keep the forum sponsors in business.

I concur with Joe; 40T is a good sprocket... Baird's bike is real fast, but he always forgets that not everyone weighs 130lbs like himself.

bairdco · #10 12-14-2010, 09:57 AM

i've had fat... uhhh... bigger people ride my bike, and they can still go fast on it. it must just be the magic bike.