SBP Jackshift Kit

A

aaronbentzel

New Member
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!
 
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.
 
Pull start is a waste of money and not needed. Centrifugal clutch is highly reccomended for shift kit.
 
kavid2012 said:
i think pull start is a must if centrifugal is being used???
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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.
 
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
 
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
 
rich4240 said:
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
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No, that wouldn't work very well at all. Gear ratios would be way too tall. Use the gear calculator to see for yourself.
 
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.
 
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.
 
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