[Cooteboy]

I just recalled there was a 3rd difference in the design - but like the porting doesn't require any modification to run. In fact the 3rd difference in my opinion should help the head to last longer. The Camshaft is longer on the older designs. It doesn't stop at the chain gear and hang in mid air like the newer engines. It extends to have one more contact point on the head to help stabilize the leverage/tension from the timing chain. I am personally glad I have the LT250 head on my bike - I'm fairly certain it will outlast the same repair had I used the GZ250 parts.

Also, I wanted to quickly explain what the "relief lever" was/is. The quadrunners were a pull start - and to relieve the pressure in the engine so that you could "easily" pull start it they had a lever that would press down on the exhaust valves just enough to keep them from seating firmly - therefore reducing compression and allowing for an easier pull start.

There is a small 5/16" hole on the valve cover located toward the front of the engine where the relief lever passes through cover itself. The way I sealed mine was by cutting/grinding the lever into a small shaft. I then cut a groove around the shaft on one end so that I could place an o-ring into the groove so that it would seal and not leak oil out onto the head.

I will try and post pictures once the weather is a little nicer. It's been raining cats and dogs adding to the MUD!