SBP Jackshift Kit

GoldenMotor.com

aaronbentzel

New Member
May 2, 2012
15
0
0
York
I just have a few questions before I buy this kit. First of all, I have a 66cc Grubee Skyhawk. Will a pull start or centrifugal clutch mod affect this kit? Also, my bike only has 8 speeds on the back wheel. Will this be alright? What size front sprocket would you suggest I get for a mix of hills and flat sections for where I live? I was just thinking a 44 tooth you be fine. Thank you so much for any advice you can give me!
 

kavid2012

New Member
May 3, 2012
75
0
0
Brentwood, Tennessee
just buy the shift kit.
it will give you access of every hill and top speed over 40 mph.
buy the HD shift kit.
you don't need to buy no extra sprocket unless you want to offroad or climb extremly steep hills.
 

maurtis

New Member
Dec 14, 2011
707
0
0
Kyle, TX
i think pull start is a must if centrifugal is being used???
I cannot vouch for using one with a shift kit since I do not have one yet, but on my single gear cruiser I am using a centrifugal clutch without a pull start. The clutch has a one way sprag that allows it to still be bump started.
 

The_Aleman

Active Member
Jul 31, 2008
2,653
4
38
el People's Republik de Kalifornistan
It goes like this: 4.1:1 within chinagirl, 1.7:1 on jackshaft (10->17). So the ratio will be 6.97:1 at the jackshaft output.

Are you familiar with the Gear Ratio Calculator? If not, get it here: http://jimsitton.net/ratiocalc/

Enter these ratios on it:

1
6.97
------
10 <----- jackshaft output gear
44 <----- outer crank ring
------
30 <----- inner crank ring
( ) <--------- enter your rear gear here
-----
26.2 <----- or enter actual wheel and tire circumference
6000 <----- "safe" redline

Using those settings you should be able to figure out your speeds @ what RPM in each gear
 

rich4240

New Member
Jun 6, 2012
55
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0
lefroy
will the engen run ok if i change the 44 to a 30 and the 30 to a 44 to achev more top speed or would it work the china girl to much
 

The_Aleman

Active Member
Jul 31, 2008
2,653
4
38
el People's Republik de Kalifornistan
The engine only has enough power to do about 40-45MPH without mods. Even with a bunch of mods you'll be lucky to see 60.

The engine won't last long at that kind of power level, either. If you want taller gearing, use an 11T jackshaft output and/or a 36T inner sprocket.
 

kavid2012

New Member
May 3, 2012
75
0
0
Brentwood, Tennessee
so far i have used the stock set up is plenty of top speed.
in fact your engine won't be able to pull up the top speed on the stock set up.
I have used 30 to have more hill climb power instead of 36 tooth stock one.
my rear cassette is 8 speed 11 t - 34 t.