Hello members,
Thank you for the opportunity to introduce myself.  A little information about myself, I am Canadian living on the west coast.  I have enjoyed owning and riding 80’s Japanese road bikes for 53 years.  Riding still connects me to my long departed youth. I maintain one large capacity road bike for two up touring with my wife. My riding hobby has expanded to include amateur restorations. I recently finished an emerald green colored 1971 Honda CT70H nut and bolt restoration for my wife to ride at the cottage. I have been an avid reader of this forum for several years.  Member contributions have made this site a valuable repository of Yamaha knowledge.  This has prompted me to emerge from the forum shadows in search of information regarding my Yamaha DT175 mono shock model bike.I acquired the bike online pre-COVID from an Arizona seller whose ownership had only been one year. No service records accompanied the bike. It is a complete 3,500 mile engine/frame matching numbers bike with an Arizona title. The only aftermarket parts currently identified are the signals, tail light assembly and carburetor (sigh).  I intend to totally dismantle and rebuild the bike as reliable rider.  In preparation I have book marked many forum discussions with questions to follow as the rebuild proceeds.The Arizona title identifies the bike as a 1981 model but the Balboa blue tank and badging resemble a 1978 model. Both the tank and side panels may be substitutions that I can sort later. I have attempted to attach a picture of the bike that I believe the seller provided me but during the process received the following forum message (Failed to create attachment directory). The bike is currently in Washington State and I will not have access to it until May of 2025. I intend to begin with the engine but need to determine the model year. The VIN# is: JYA3J1003BA067149. I have reviewed the forums VIN# table look-up but could not find any reference to a JYA prefix.  Several hours of internet searches have not helped.

 Any thoughts folks and thank you in advance.Cheers ringding1017

It's a 17 digit VIN mandated in the USA to be used on vehicles manufactured after Jan 1st, 1981, although some manufacturers started in 1980.  Yamaha seemed to wait until the last minute.  I have even owned a 1981 model DT175 with the full 17 digit VIN on the title, but the frame stamp and engine stamp were the "short" versions.  

Long story short...  by that VIN, you definitely have a 1981 DT175...  very late production in fact.  

You should have leading axle forks and the 1979-81 US fuel tank shape is much different compared to 1978 (non leading axle forks in US) to allow for steering clearance.  Also, your air filter will be on the left side of bike and oil tank on right side....  a 1978-79 has sides reversed and very different oil tank and air filter parts. 

Yamaha's only color listed for 1981 was red...  but bikes get repainted and re-decaled...or someone could have installed a 1980 sapphire blue tank because they wanted a blue one?  Dealers and owners have been known to do such things.  Pics would be helpful, you must use a 3rd party site like Imgur to host photos and link them here.

P.S. A 1978 tank or side panels will not bolt on to a US 1981 frame without modifications.  Earlier seat may be slightly different as well.  Plus steering would hit tank unless someone installed non-leading axle forks and clamps. 

Greetings from Tennessee