the rumor mill has fired up

[Doc]

Have a look at the frame loop that goes up under the tank on the pics of the '65? models you found. Compare to the frame design on the 90 and there be similarities that are not to be found in suzuki MX or offroad frames designed after the late 60's. Now, what's the Japanese picture for hello?     

[GD66]

I vaguelly remember, ( vague i do well) suzuking fudging the ad machine  in the 70s. the 125 may have won a road race in 70 and the 250 in 71 and the 500 in 72. the statement still stands correct as suzuki being world champs in 3 consecutive years but......

Hmmmm, tenuous at best. I can tell you OTTOMH that Phil Read won the world 250 title in 1971 on a privateer Yamaha, and that Ago was the 1972 world 500 champ. Maybe they were world champs at sticker production....

[pokey]

Am conviced its a pre unit  job  but the rest of the bike  I dunno, the rear top shock mounts are more honda style , Frame looks like its twin downtube Hmmmm...Im not sure its entirely suzuki. not unless that engine is from one of the tiny road racers from the period with 6 millioms gears , they were disk valves and had the carb on the left

[Doc]

Pokey that road race motor theory might hold true. The RM-RT62/63 single cylinder 125cc and 50cc racers of the early 60's did indeed have the carb on the left and ignition on the right. I have just noticed the Colleda model of 1959 that  Kazuo Kubo won on was also designated as RA125 by the factory. This could be the bike (modified for MX) mentioned winning the all japan series of '59. (picture below) Thing that dispells this theory is with the next model the designation changed to RB125 which meant the RA was no more. At least not till it resurfaces in the late 60's, early '70's. I give up and the letter to Hammamatsu will be in the mail pronto