Kawasaki Z125 Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
Hey Guys!

New to the forums!

My tiny roommate has a 2017 KRT, before her larger tire she was getting 67mph at red line with bike 100% stock (she only weighs 120 dry). Now she upgraded to 130/70r12 tire rear and now speed stays around 56mph and wont come close to red line. Went ahead and put in a 28t rear sprocket and no change.

I (significantly larger man) own 2017 pro and i upgraded to a 140/70r12 and i'm in the same boat. But i went to a 15t in the front but haven't had a chance to try it due to not getting my plate from the dealer.

Anybody have any ideas on what could be wrong?
Thank and hope to here from you guys soon.
 

·
Registered
Joined
·
4 Posts
Having the same issue. I'm thinking about getting the bazzaz fuel mapper/controller + intake and exhaust to gain some power back but would hate to spend so much money if the issue can be resolved with simply going back to the stock tire size even tho the 130/70r12 looks a lot better on the bike.
 

·
Vendor
Joined
·
747 Posts
You can measure actual tire OD (rollout) combined with gearing changes, and mathematically find what your final gearing is. Ultimately, going to the wider & taller tires have given you taller gearing, that your current motor setup doesn’t like to pull. The solutions are (a) gear it correctly, or (b) add more power.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #4 ·
Thank you for the reply
I'll more than likely go with trying different gearing just because its cheaper, power later. Would you know the equation to find the proper gearing?
 
1 - 6 of 6 Posts
Top