My motorized bike topping out at 20mph

Juicecupp

New Member
Sep 15, 2021
3
1
3
16
Hi guys my motorized bike i bought a bunch of upgrades like the bbr thrust exhaust, performance carb with better air filter, new gas tank, new cylinder and cylinder head, and it keeps topping out at around 20mph im new to motorized bikes and just got this like a month ago and only been riding it for about 2 weeks, it accelerates pretty good to about 20mph but then just stays at that speed, i do have some throttle slack but dont think that is the problem, also can anyone tell me how to fix my throttle slack like with some type of spacer or something, and when i go out to my garage like in the morning or something i will see a really small wet spot on the floor so i think my gas is dripping even tho i turn off my fuel
 

wrench

Well-Known Member
Aug 20, 2019
345
306
63
So Cal
I'm not saying that this is your issue with your M/B,
Check your carb float it might have a hole in it. As many have had problems with a pinhole in their float.

Throttle slack - have you adjusted the cable barrel and on most carbs there is also a slack adjustment where the cable hooks to the carb.
A little throttle cable slack shouldn't be a problem though, as long as the carb slide goes all the way up like it should
 

Juicecupp

New Member
Sep 15, 2021
3
1
3
16
I'm not saying that this is your issue with your M/B,
Check your carb float it might have a hole in it. As many have had problems with a pinhole in their float.

Throttle slack - have you adjusted the cable barrel and on most carbs there is also a slack adjustment where the cable hooks to the carb.
A little throttle cable slack shouldn't be a problem though, as long as the carb slide goes all the way up like it should
Heres the thing my brother put my carb together and i took it apart yesterday and did not see the needle except i did think i saw it stuck in like the bottom of my carb and ima prolly have my uncle check it out and yea all of the adjustments for the throttle are dont but theres still slack
 
  • Like
Reactions: wrench
Dec 11, 2014
615
6
18
Tucson
Did you get this resolved? Step one I would recommend is putting the stock carb on and getting it tuned and running right that way first. You will not make more power with anything but the stock NT carb on a stock motor.
 

Testname111

Active Member
May 20, 2021
121
39
28
32mph my top speed with the 36 tooth gear, but I'm beginning to suspect I'll never get any fast with the more air/mix in = more out = top speed, can only be achieved with a tuned carb as long as the physical intake where the slide is bigger than that stock not carb opening/slide area
 
  • Like
Reactions: Denis Zen