HD GUIDE REPLACEMENT
On older Harley Davidson Pan, Shovel, Ironhead and many other cylinder heads, flanged guide removal can lead to damage to the host bore in the head. Many times the guide is distorted and will tear up the bore as it passes back through. To stop this, use a guide boss cutter that is smaller than the guide and simply machine away the whole top flanged guide flush to the head. Then, heat the head and drive the guides out from the spring side to the port. You will need to cool the head and mic the guide bore to get the correct oversize guide sizes and hone for an oversize guide, if needed. I like to machine them from oversize guides, in the mill, holding the guide by the collet and turning it against a fixed bit in the vice. While I do this, I will also machine down any guide length that is hanging in the port to reduce wear on the head’s guide bore while pressing them in. Tapering the intake guides is a nice touch.
Ron Flood
Cedar Machine Service
North Branch MN
January, 2016
