Heres a nice simple revamp of a 360 MX. While I like the blokes individual take on the bike, I've got to question the swingarm. It's probably legal by their rules but definitely ilegal by ours. Despite there being no historic precedent for those arms, Aussies keep buying them because they "look cool". The sooner the swingarm section of the rulebook is tightened up the better. The head National scrutineer agrees with my take on them so check before you spend your money on something you may not be allowed to use in open competition.1973 Yamaha 360 MX
This bike was given to customer Shawn McDonald, the Publisher of "Bench Racer" magazine, by the "First American" Jim Pomeroy. Jim never actually raced the bike, but wanted it to go to some old racing friends from back in the day, so that they could enter the world of vintage MX racing. The first racer was childhood friend, Yakima, Washington neighbor, and toughest opponent Rick Poulin. It didn’t even last one moto as the pipe fell off at the cylinder at the Dinosaur Daze race. It did get Rick started in the world of vintage racing though.
It was determined at that point that Full Circle Racing would take over a complete restoration of the bike to a better than NEW condition. Sitting down with the customer it was determined and agreed upon that why restore a historically ugly bike to N.O.S. condition especially since the restored value would not be anywhere near the restoration costs. Let’s give it it's own look that would not easily be identified by a non vintage motorcyclist. Let’s hot rod the bike for looks and performance.
After dismantling the bike and tagging each part it was determined what, when and for how much each part would need to be modified, replaced or restored. The original frame while useable for racing had smashed frame tubes under the engine attesting to a previous life as a trail bike. An alternative Yamaha SC 500 frame was found which then was media blasted and powder coated black. The steering head ball bearings were replaced with "ALL BALL’s" tapered roller bearings. The Yamaha’s were notorious for their twisty, twitchy handling under power. Back in the day legendary desert racer Al Baker fixed the problem by selling a 1 ½ inch extension kit for swing arm length behind the shock position. This provided stability under power. It also unfortunately lengthened the wheelbase which was great for desert, but would make it harder to steer in slower motocross corners. Working with Novation Racing (novationracing.com) in Spokane, Washington, a prototype box aluminum swing arm was constructed with an additional 1" of length which is now part of their catalog. To handle the rear suspension a Works Performance dual rate gas shock was used with a 14 inch eyelet to eyelet length. The extra one inch of swingarm length, along with the longer shock, raised the rear end thus quickening the steering. The extra 1" of swingarm length helps put maximum horsepower to the ground and reduce useless wheelies. The stock ridged Japanese rims were replaced by brushed aluminum Sun rims with Buchanan’s stainless steel spokes and trued by Full Circle. The brakes were cleaned and replaced. The front forks were spaghetti and were replaced with straight newer tubes. Fork springs were replaced with Progressive springs. Fenders are white Vintage Iron replicas. Cables and levers and perches were replaced with N.O.S. The throttle is a Gunnar Gasser and handlebars are aluminum Malcolm Smith models. A very hard to find N.O.S. carburetor-airbox boot was found. The cylinder, head and carburetor were media blasted from black to silver in an effort to brighten up a previously dark bike. The tank is from a 1976 YZ 125 and was found with no dents. The tank mounts on the front and rear of the frame were relocated to accept the new tank. The tank was brought to Mitch McAllister where it was prepped, painted and masked for a classic 1950's custom car flame job with five different different pearl coats to sparkle in the sun. A custom aluminum red anodized gas cap was made by Novation Racing. Mitch also painted the side panels white to match the fenders/tank. Because the seat provided for much of the suspension back in the 1970's the seat was custom made using the highest density foam available. It was raised 1 ½ inches in the front and tapering down to 3/4 inch raise at the rear with a custom made seat cover for a one off factory look. The stock expansion chamber was replaced by a Circle "F" pipe. Because the riders complained that the pipe stuck out to far and burned their legs the pipe was cut and re welded for proper clearance. The pipe was then ceramic coated, keeping heat inside the chamber and keeping it cooler outside. The silencer was replaced by an aluminum oval FMF silencer cut to length. The engine was taken apart to remove the counter balancer and a PVL ignition replaced the faulty stock ignition. An 8 oz weight for more flywheel effect at lower RPM’s was also added. A new bore job and top end were installed and the gearbox was freshened up. What also was found were some built in finger ports and exotic porting in general. Bolts were replaced with grade 8 or SS bolts and clear gas tubes were used for all exterior tubing. Michelin MX tires, tubes, gold DID chain and new sprockets finish off the bike.
The bike was first put into the hands of ex factory Honda star of the early 80's Phil Larson jr where he won the highly competitive 40+ Expert class in multiple races. The biggest prize was at the 2004 Vintage Iron World Championships by winning the 40+ Expert in the vintage class and then the next day winning in the two-stroke class. Then it was handed to 1970's racer Doug Raines who bumped up to the 50+ Expert class where he won every where he showed up at. Next up was Mark Kaestner, another top 1970's racer, who went undefeated in the 50+ Expert class. Out of 28 starts, 26 of them were hole shots. Phil commented that the bike in a straight line had as much horsepower as his factory Honda’s in the early 80's. Everywhere the bike goes it gathers crowds either at the racetrack or on show at a dealer. Mostly they say "What is that?"
