Roketa DB-28 BBB 110cc Chain and Sprocket Questions

[Kevbo]

1st gear seems pretty useless on this bike. I heard if you upgrade the sprockets, you can get a little more use out of 1st gear and possibly more power too? Anyone know if this is a #420 or #428 chain? How about the sprockets - Would I need both front and rear? What teeth count is best to achieve the best performance? Any help on this would be great!
Thanks!

[katoranger]

I think that alot of the pit bikes came with a 420 chain. What sprockets do you currently have? # of teeth.

If first is too low add a couple teeth to the front sprocket. Much easier to change and you will probably get what you are looking for.

[Kevbo]

Thanks - Do I need to swap out the rear or just the front?

[katoranger]

You can change just the front.

[Weldangrind]

Our 125 pit bike (a Gio) had a 428 chain. you could likely take the existing front sprocket into a bike shop and ask them to wrap some chain around it to be sure.

Check out this gear ratio chart from JT: http://www.jtsprockets.com/fileadmin/files/jtgearratio.pdf

Let's say you have a 14 tooth front sprocket and a 36 tooth rear; that equates to a 2.57 ratio (which is waaay too high, except for land speed records). Switching to a 12 tooth in the front would result in a flat 3.00 (much better).

Don't go any smaller than 12 teeth on the front sprocket, because it becomes too small of a radius for a chain to articulate around at high speed.