XS6501B rolling project

[airbusflyboy]

Just picked it up yesterday down in Mississippi, was stored away in a shed building of sorts, out of the weather. Frame and Engine numbers match, looks like the Candy Orange paint job that was sprayed over with paintcan. Question : From the frame and engine number is there any way to determine the exact MONTH and DAY this was built ? The range looks like August '70 to July '71 ............... The frame tag is worn pretty bad and hardly any legible print on it but I can make out something that looks like 19--
Any pointers or advice on how to determine month and day of mfg. besides that tag, would be appreciated !!! If there is anyone in the MEMPHIS,TN area that has similar bike, please drop me a note ..............

 

[Dennis]

I dont think you can tell the day but you can decipher the month

 

[airbusflyboy]

OK ............. do you know how this works to decipher ?

 

[XSLeo]

Most of the white stickers have the month and year printed on them. If you can't read it then you can't read it. Not a problem really. The only thing you really need to know is the year it was made to be. As your XS1B is a 71.
There were some mid year changes. You can read about these changes if you find a Yamaha factory manual, there are parts and service bulletins that explain the changes. These changes are by engine or frame numbers.
Like in my 70-74 Yamaha book there is one that applies to the XS1B. They shaved a flat spot on the top of the piston, 1.2 mm was removed from the top of the dome to reduce compression ratio from 8.7-1 to 8.1-1 for a more stable engine idle.
This started at frame #23130.
May I ask why you feel you need to know the day, month and year it was made?
Leo

 

[airbusflyboy]

Thank you for the tip, my other cycles have a readable data tag, we believe this to be XS1B due to the the following numbers found on both frame and engine : S650-022394