Cam Identification and info 
We sell a number of performance cams that fit into most Pitbike engines
we ONLY have upgrade cams for Round cam cover 50-150cc engine 
(we do offer replacment cams for Diamond / 4 fasterner cam cover KLX type motors)
In general Cam shaft TBW0411 fits into China 50-110cc e22 head engines
Once we go bigger than that we need to measure to be sure

 
EXAMPLE:
TBW0300 Race Cam :
2 Bolt type
This is how the cam gear attaches 
You must run the same number of teeth on the new cam

Legnth 70mm center to center. 
(your new cam must be this legnth) 

42mm large bearing, 28mm small bearing
Small End bearing are easily interchangeable with your stock cam
(so you can swap your stock small end bearing IF you need to for the correct OD , But not to change the legnth

So Please review Your cam and the cams we offer to determine what you need to buy 

Understanding Cam Gear Ratios 

4 Stroke engine crankshaft/camshaft gear ratio is always 2:1, which means that for every two revolutions of the crankshaft the camshaft will rotate through one revolution.
This is a 2:1 ratio and must always remain 
The top cam sprocket will have twice as many teeth as the crankshaft cam-chain sprocket. 
Typically, Honda 50 and 50-110cc Chinese engines and Lifan 140, have 28 tooth cam sprockets.
Jailing and GPX and YX 140 engines have a 32 Tooth cam sprocket.
When installing a performance camshaft you may replace the cam sprocket but only due to the bolt pattern. 
The new cam sprocket must have the same tooth count as the original sprocket.