I had the privilege of meeting Lee Mallet today, the guy who built the yellow racer that we admired a couple of years ago when it came up for sale. In between customers he told me a little about the project.
He had brought an XZ550 new back in the 80's and always reckoned they would be a great bike for track modifications. This one started as a rusty wreck and over a couple of years and a couple of hundred hours it morphed into a respectable race machine.
The whole of the rear frame of the bike was chopped off, rebuilt, stiffened and lightened.
He reckoned that the biggest problem with the XZ was that the engine was badly choked by a restricted air intake and restricted exhausts. He retained the Mikuni carbs but cut away the rear half of the top of the airbox - getting rid of the flapper. The carbs then had their jets drilled until, by trial and improvement he reached an optimum performance. Alongside this the exhausts were opened up by replacing the thin twin wall sections and the collector box with siamese header pipes front and rear with a separate exhaust for each cylinder. (38mm pipework?)
Lee reckons that the mods nearly doubled the power output.
The design of the faring is based on a Buell racing machine.
On the track, clearance became a problem with the oil filter scraping on the ground. To protect the oil filter and water pump housing from injury he built a stainless steel cover which can be seen in jpg #1. The bike was mostly used for track days at Manfield where he would sometimes join up with the Whanganui based Bernard Racing Team (Yamaha). The paint and graphics are in the team colours. The hydraulic activation of the rear drum brake was another mod born of track experience. The rear set foot pegs meant that the footbrake pedal was almost at 90 degrees under heavy braking. The hydraulic setup (made from a Toyota Hilux master cylinder) meant that he could use a very short lever action to activate the braking. Note the front brakes are all original but with stainless steel braided lines.
The XZ was sold because of too many other projects in his workshop. The new owner lives in Pukekohe, near Auckland. The photographs are from Lee's listing when he sold the XZ.
