Here is a tutorial to flash VIBEUI ROM running KitKat (4.4.2) on Lenovo S650 :-
If ur current ROM is ROW , follow 01-22
If ur current ROM is CN , follow step below 05-22
If ur current ROM is VIBE, follow step 13-22

Download all items below :-
1.Flash_Tool
2.S650_S119_131014
3.VRoot
4.TWRP_v2.6.3.0_CN
5.4.4.2_GApps
6.SuperSU_v1.94
7.VIBEUI_V1.5_1415_3_DEV_S650_NK_W_A291

Copy item 5,6,7 into ur ext sdcard

Install USB drivers 1st...


How to Flash...


01. Off ur hp and take out the battery
02. Extract and Flash "S650_S119_131014-Lang_Fix"
03. Once finished, close flash_tool app and disconnect usb cable
04. Insert battery and turn it on, let it boot once
05. Root using "VRoot"
06. Install "MobileUncle MTK Tools" from Play Store
07. Off ur hp and take out the battery
08. Run flash_tool again
09. Extract and Flash "TWRP_v2.6.3.0_S650_CN"
10. Press F9 and answer YES (Don't press F8)
11. Once finished, close flash_tool app and disconnect usb cable
12. Insert battery and turn it on
13. Click 10x "Build Number"
14. Enable "USB debugging"
15. Reboot in Recovery via "MobileUncle MTK Tools"
16. Wipe dalvik cache , cache and data
17. Install "VIBEUI_V1.5_1415_3_DEV_S650_NK_W_A291"
18. Install "GApps"
19. Install "SuperSU"
20. Wipe dalvik cache and cache again
21. Reboot
22. Once ur hp boot, press + for English

List of apps can be disabled in Titanium Backup :-
youyue
lenovostore
secureit
shareit
syncit
mobileassistant
lenote
gameworld
sinaweather
lenovoservice
tutorial
usercenter
browser (replace with ur own browser)

mynet
Kindly pin above steps in 1st page