Extended intake rocker arm for more ratio and more lift

A couple people said they were interested in this so I decided to show it. Its just a rough idea and needs testing/refining but its simple and appealing. Replace the tappet screw with a hardened 1/4" fine thread bolt. You don't need to re-thread the rocker. The bolt will just barely fits through the existing threads. Use a replaceable horse shoe shaped washer clamped between the rocker and the smoothed off bolt head to adjust valve clearance. The washer in the photo is alum that was simply cut with a wire cutter and filed. The bolt head surface could be at a slight angle and be turned for fine tappet clearance adjustment or you could have a variety of horseshoe washers. The slot in the horseshoe washer is located in the photo for viewing but it should really be turned so the slot is away from the valve tip contact area.

With this setup you can re-angle the valves, move the entire valve guide and locate the valve tip further outward another 2 or 3mm to change the rocker arm ratio. That's enough to get another .030" lift. More would be available if you had a larger diameter bolt head. Its similar to an oversized mushroom tappet but it won't break because the bolt head is supported at its circumference (unsupported mushroom tappets are stressed and can fail). I haven't sourced hardened bolts other than grade 10 bolts but something should be available. Or make your own with hardened tool steel. Its not something I am pursing because I'm not racing but anyone could pick it up and take Nortons a little further.

Combining this rocker extension with a Sifton 480 cam - you should be able to nearly match the valve lift and duration of the Harley XR750 ML cam and that's never been done before.