Basically, I've got a mongoose backbox that has a silencer on, a (Cheap one I think its a very luminous green whatever it is) carberuttor filter, and a 1.4 cvh.

Is there anyway I can get a bit more of a grunt, without removing the silencer..Or putting a new engine in? lol

 

drill holes in it

 

cut open the back box and take out the baffles, weld it back together

 

nah dont take the sliencer off as then you will have no back pressure.

CVHs have a problem with eating cams, even after 50k the cam is extremely worn. Buying a new standard one will transform it, it did in mine. I used ultra parts, the kit was around £110 and made a huge difference. The good thing about the cvh is the head doesnt need ot come off!

Also the standard carb is very restricitve, you could use the tldm off the later xr2s but they arent much cop, try and find a manifold and carb from the early xr3 or the pre 86 xr2, as these will flow much better!

With all this you probably make a good solid 80bhp rather than the 65-70 you are getting now, due to the worn cam! I did try an xr3i cam in mine but you had to time it perfect as the overlap is too much for the 1.4