I need technical help

J

JamesWolfgang

Hello im James. I have a couple of questions for you tech guys. I have a 200cc lifan 5speed. The gear ratios are 2.769, 1.882, 1.400, 1.130, 0.960
I need to figure out what the final rpm of the motor sprocket will be in each gear at 8500 motor rpm. Can anybody help?
 
O

ossagp

you need the ratio of the primary gears (crankshaft and one on the clutch) before you can know. So I assume you are asking for that gear ratio. I dont have it, but if you have the bike it is not too hard to find it.
 
SRAD97750

SRAD97750

Moderator
Staff member
JamesWolfgang:
Hello im James. I have a couple of questions for you tech guys. I have a 200cc lifan 5speed. The gear ratios are 2.769, 1.882, 1.400, 1.130, 0.960
I need to figure out what the final rpm of the motor sprocket will be in each gear at 8500 motor rpm. Can anybody help?
Click to expand...
I have a few of the same bike. What are you looking for in all this?

Primary reduction is ~4:1 on these motors.
Otherwise it's very simple math.
(Engine RPM/4) then (Clutch RPM/Ratio)

Sprocket RPM
1st- 775 RPM
2nd- 1129 RPM
3rd- 1518 RPM
4th- 1881 RPM
5th- 2213 RPM

Which, with an 18" wheel (66 inch circumfrence) and stock gearing (13/35)(2.69:1) is a 'mathematical theoretical' top speed of...

1st- 17 MPH
2nd- 27 MPH
3rd- 36 MPH
4th- 44 MPH
5th- 51 MPH

Good luck... I find mine top at about 65 mph in 5th gear pinned with stock gearing, downhill, with a tailwind.
-BIG DAN:thumb:
 
SRAD97750

SRAD97750

Moderator
Staff member
CDA:
Why ?
Click to expand...
These engines are ROCK SOLID but come in the most horrendous frames and models of china bike... The bikes themselves are atrocious.. The engines on the other hand (163 and 169 models) are awesome for small projects, modifications, and all around FUN.
He might need sprocket rpm for deciding which sprocket to fab up onto the axle for the special project. :noidea:-BIG DAN

Here is where I used a 163fml for my favorite pitbike. It is a TRACTOR.
https://www.dirtbikeaddicts.com/content/threads/sneeze-163fml-chinazaki.1992/
 
Last edited:
CDA

CDA

SRAD97750:
These engines are ROCK SOLID but come in the most horrendous frames and models of china bike... The bikes themselves are atrocious.. The engines on the other hand (163 and 162 models) are awesome for small projects, modifications, and all around FUN.
He might need sprocket rpm for deciding which sprocket to fab up onto the axle for the special project. :noidea:-BIG DAN

Here is where I used a 163fml for my favorite pitbike. It is a TRACTOR.
https://www.dirtbikeaddicts.com/content/threads/sneeze-163fml-chinazaki.1992/
Click to expand...
:thumb:
 
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