I have a question about the RT1.
There is someone in one of my vintage groups who has an old rusty RT1. 1971 360 with what looks to be an aftermarket seat cover.

The seat has stitching in the shape of a spider web.
He claims it is a Japan only model, less than 100 were made, called the ‘black widow’ and the seat was special for that model AND it has a special big
Bore 360 which is larger bore than a regular 360.
It’s faster than a regular rt1 he says. Like ok I thought it might be the rt1mx with the GYT stuff but not even, the pipe is the enduro version with the chrome guards etc. nothing on that one says anything to me except old RT1 with a weird seat cover.

He also claims that a ‘bighorn’ was a special model of F5 that had a ‘big bore 350‘ bigger bore than a regular 350...a bison was a special F8 that has a ‘big bore’ 250.
I know he’s full of crap on that, that’s MY wheelhouse, old Kawasaki rotary valve enduros.

As I type this I’m laughing to myself. This guy is a hoot . So what about it Yamaha guys? How about that black widow RT1...less than 100 were made —I told him he’s full of shit but somehow wanted to double check. I know they were black in 1971 maybe that was a nickname? (Black widow)

He also informed me that the fender brace on the bighorn was in fact a factory mud scraper to keep mud off the front tire. I mean I guess it would...

Soooo.... you wanna ride or sell ?????

Any photos available to post?

This is the only pic he has on the post.

There was an aftermarket "big bore" kit available yamaha-enduros.com/index.php/forums/gene...y-big-bore-kit#43463

So there is a chance it could have a bigger bore... just not from Yamaha.

My B.S. meter is pegged on the rest of the story...

400 has to go to 85mm but i tried that on my RT2MX cylinder & went to alloy in places heading up through the transfer area. Really peeved off with myself over that--45 years later lol. Can go to 82mm safely with a 'one year only' "79 YZ400F piston with slight skirt mods as about 5mm too long to be safe. Anyway, that's not helping the story sorry. Looks like an RT2 tank so probably 'is' RT2. Good story though & let's hear more of them lol,

Good stuff, old saying history is written by the winner, guess sort of applies here, once had a customer that owned a 1972 Yamaha Texan, he was certain it came from Yamaha with Texan written on the tank, is did say Texan but it didn't come from Japan that way. Anyway I just wrote Yamaha Texan on his work order and he went about his happy life him and his Yamaha AT 125 Texan model

Hey Mark when you say B.S. meter do you mean BEST STORY or what ?

I challenged dude with the Black Widow as well. He fired right back that his brother got this special "big bore 360" from Japan. I let it go so as not to pop his bubble, and knew there was no changing his mind, or, he's just looking for a "virtual fight." Some of his responses:
"This is a 1971 and all original. It was imported from japan in 1971 when my brother was stationed in japan it cant be a 1972 because he baught it before he came home in late 1971."
"This is not the normal 360 rt1 you keep talking about the enduro ones this came strictly off road. And it was called the black widow. Hence the original spider web seat on it"
"This did not come with a head light or tail light . It was a promotional bike. For strictly racing off road amd it is a big boar 360 not a normal rt1 360"
"Yamaha not enduro dirt bike only no tail lights no head light. No turn signals."

I have a JDM RT2 brochure , which was printed in June 71 , so it is entirely possible that the bike
was purchased in Japan mid to late 71 . The rest of the story is a bit harder to swallow .
Even if Yamaha made a special seat cover , for a limited edition , it's hard to believe they
wouldn't have stencilled their name on the back of the seat .
Another possibility was a custom shop in Japan fitting out a new RT with custom goodies .
It's a bit hard to believe Yamaha could be bothered with a limited run of 100 .