MXA test rider Willy Musgrave puts an ADB Avenger 600 through its paces.

Motocross history is filled with creative ideas that were heralded as ground-breaking, some were abandoned, others stupid and a few were truly innovative. Do you remember the ADB Avenger?

You’ll need a program to keep up with the storyline behind the Avenger motorcycle. As with all American-designed motocross bikes, it starts with Horst Leitner. The Austrian-born, but American-based, Leitner founded ATK Motorcycles in 1982, but in 1990 he left ATK to start AMP Research. ATK was taken over by Ken Wilkes, who sold the company to a Utah-based investment group, but the deal between the two went sour. While the Utah group continued to produce ATK motorcycles, Wilkes formed a new company called ADB (American Dirt Bikes), which started selling spare parts for older-model ATK’s. It was a messy situation. As for Horst, he had no financial interest in PBH or ADB once he cashed the design check. AMP Reasearch went on to design mountain bikes, automobile parts, Bed Extenders and for motocross, the AMP Research KTM 125 prototype for Mattighofen.

Horst Leitner was commissioned to design a ready for production, prototype 600c four-stroke for the British PBH company. It was assembled in England, but sold under the name Scott. It uses all of the classic Horst Leitner touches; straight rectangular chromoly frame, countershaft disc brake, laid-down no-link shock and ultra-slim dimensions.

Meanwhile, Scottish Grand Prix racer Vic Allen approached AMP Research about building him a prototype, 600cc, four-stroke, motocross bike for the British-based PBH company. AMP built PBH a prototype, which was taken to England and marketed under the name Scott. But, Scott (PBH) went bankrupt and Ken Wilkes bought their left over stockpile of AMP-designed bikes, moved them to ADB and labeled them the ADB Avenger (the Avenger name was a barbed reference to the Utah ATK group). But according to ADB, ATK pressured Rotax to cut-off ADB’s supply of engines. ADB sued, and by the time the suit was settle, the Avenger was history.

A 1996 ADB Avenger stripped of its bodywork reveals the rear suspension design.

With the bodywork in place the ADB Avenger looked bigger and heavier than it was (note the difference to the photo above). Horst didn’t want the bodywork. He favored the slim Scott PBH gas tank look, but got paid to design the bike, not the cosmetics.

Are you still with us? Here is a recap. The original ATK founder sold ATK and started AMP. The new ATK owner sold ATK to a group in Utah and the old ATK became ADB. AMP designed a bike for PBH. PBH went bankrupt and sold the AMP design to ADB. ADB started production of the Avenger to get even with the new ATK. Old ATK, now ADB, sued the new ATK, plus Rotax, and by the time the dust settled only ten ADB Avengers were ever produced.

Horst always consulted with MXA’s Jody Weisel on every design, used him as the prototype test rider and listen to him on technical features—but got nervous whenever Jody fired up the electric eraser over the blueprints.

Today, the ADB Avenger is kaput. ATK Utah has been sold, bought and rebought several times. And AMP Research thrives in the automobile business.


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