Would there be any advantage to putting a XL125 head with the larger valves on a TL125 ?

Would there be any advantage to putting a XL125 head with the larger valves on a TL125 ?

If your going to that much trouble, just make the hole in the cylinder bigger for guaranteed results.

Would there be any advantage to putting a XL125 head with the larger valves on a TL125 ?

Hello showtime45

I have a couple of TLs and have found that the Miller 150cc kit has a very thin spigot and although I have had one sitting in my shed for some ten years I am wary of using it because of spigot failure/cracks, however if you are using the bike for twinshock trials it should be ok,

Bigger valves would help the bike to rev higher but would rob it of some torque in the lower rev range.

Regards Rocker1

Would there be any advantage to putting a XL125 head with the larger valves on a TL125 ?

The XL head has a combustion chamber volume of 15cc (measured by myself) as compared to 12cc (from info on the net) for the TL. If you fitted the XL head with the standard TL dished piston (the XL has a domed piston) the comp ratio would go down by about 1.5 points. The TL has a low ratio to start with so I think it would make it too flat.

And as mentioned, bigger valves also rob the engine of low down torque.

I think the 150 might be the way to go too. Or a XR185/200 engine swap..Thanks for the info...