Aamrr Championship Yamaha Ta125

AAMRR Championship Yamaha TA125

From Basket Case to Formula IV Winner for $1150

John Ulrich

In most parts of the country, including the Southern California hotbed of road racing, Honda MT125R Singles have taken over the 125cc GP class in clubman events. But Bill Payne 38, a Southboro, Massachusetts, truck mechanic, won the 1978 American Association of Motorcycle Road Racers (AAMRR) Formula IV Championship with a TA125 Yamaha he bought in a basket for $150.

AAMRR is one of the country’s oldest and most competitive road racing clubs; Payne’s efforts don’t classify as “cherry picking.” Formula IV includes 125cc and 200cc two-stroke Twins, 250cc two-stroke Singles, 250cc four-stroke Twins and 350ce /our-stroke Singles. Entrants have included Mike Baldwin on a Reno Leoni Ducati 350. When Baldwin raced that Dueati at Bridgehampton, he lowered the Formula IV class lap record to 2:03.5. from the 2:05 held by Payne at the time. Payne subsequently took the record down to 2:03.2 with his TA 125. The most competitive MT125R Hondas in the class typically lap at 2:07.

Payne entered nine AAMRR races and one Western-Eastern Roadracing Association (WERA) race in 1978. H e won seven with two DNFs (one when the clutch failed and another due to transmission problems). Payne was fast qualifier by a one-second margin at the Honda Challenge, a support race held in conjunction with the FIM F750 World Championship round at Mosport. Canada, and led the

race until it was stopped by a massive group crash.

The key to Payne’s success isn’t inherent in the TÁ125. Instead, it’s what Payne has done with the bike he bought in pieces. The machine now sports Red Wing accessory forks and extensive swing-arm and swing-arm pivot area gusseting. The rear shocks are 11.7-in. Konis with the lower mount moved forward 1.5 in. and heavily gusseted. The change to longer-than-stock shocks and the relocated lower shock mount combine to produce 4 in. of rear wheel travel, extraordinary for a 125cc road racer.

The original TA 125 drum brakes have been replaced with discs front and rear. The front disc started life as a Kawasaki KR750 part, and is plasma-sprayed aluminum. The front caliper is Lockheed. The rear disc is also plasma-sprayed aluminum, originally off a KR250 Kawasaki, with a Grimeca caliper.

The cast Campagnolo wheels used by Payne are the same width, as the standard TA 125 spoke wheels, but are fitted with a 3.25-18 S41 PZ4 Michelin in the front and a 3.25-18 SV12 slick on the rear. When he first showed up at a race with the huge tires, says Payne, observers thought he was crazy and declared that the big tires wouldn’t work on a 125. Obviously, Payne’s tire choice—which he says allows him to gas it earlier at turn exits and to overcome the Honda Single’s better drive—has been vindicated by his success. In fact, he reports that many of his Hondamounted competitors are having custom swing arms made to allow fitting the large tire combination to their MT125Rs.

Payne’s TA 125 air-cooled engine has been ported by tuning wizard Kevin Cameron, who also built the exhaust pipes.

Payne estimates that he has put about $1000 worth of improvements into his TA 125. Combine that with the $150 he originally paid for the basket-case bike, and you’ve got an $1150 championship machine.