Engine?

[Harfi]

hi all im new here and im looking to get a new engine but i do not know which one to get i have about $600 to spend on one and i was looking for a 125 and then tune it.I ride mostly field but do go some tracks, so i want an engine that will have power (enough to be the same speed or faster than a thumpstar 120) and will be very realiable. I was thinking of a GWEI from ooracing but they said to be able to tune it i would need a begger valve head and a liffan would fit but they are about $200 so is it realy worth it but the spec on that engine seems to be very good with shed loads of tourque. if i got the GWEI would i be able to put a 138cc head on it and bore it out?

OORacing - performance monkey bike, pit bike, madass, zoomer, dirt bike components - NEW 125cc Off road 8.2 bhp full engine kit with new type 5 plate clutch (Powered by CubeCart)

I want a engine that is not that popular as im doing a project and i want it to be a little bit different.
I have also found this engine and it seems to be good form the spec but i do not know what it is like with realiablity. What do you think the tuning cababilitys would be?

Westbank Imports

thanks
harfi
and sorry about all of the questions

 

[DDR200supermotard]

hey mate just so u no this is a australian site dont mean to scare ya away but do u think you could convert that to ozzy dollars becauseits quite a bi different and i no that 1 pound is more then an ozzy dollar so yeh but from wat i think yx140 would do the job great

 

[Harfi]

oh im from UK sorry urm i dont know how much it is in $ but i fink it will be about double sumfin along them lines.

 

[motoluver]

Looks like a jailing motor.

 

[Harfi]

Looks like a jailing motor.

which one ? are jailings good?