In order to get my bike licensed for the road I need something from Yamaha that says it can take lights. I have installed the original Yamaha lights and brakes but I need a copy the paperwork from Yamaha, a bulletin or something. Know where I can get it? Thanks. {Richard, WA 1979 Yamaha 175cc MFX [GTMFX]}
I have checked the microfiche cards for the 1979 GT175MFX. They do not contain or reference
technical bulletins pertaining to adding lights to make them street legal. Similarly, I did not find any reference to this situation in the
Factory Modification Campaign notices.
I assume that the problem lies in that the Washington Department of Licensing enters the VIN and it comes up as a dirtbike without proper lighting for street use. You have made the necessary changes, but the DOL computers will not let the registration (or license) be issued.
WA DOL website has information about re-titling salvage vehicles after they have been fixed. They probably have a similar process for custom built, homemade and modified vehicles.
This should be the first method you investigate. You probably will need a notarized statement from a Yamaha dealer stating that this bike is suitable for modification and will function safely and properly now that it has been modified as part of your documentation. This process can either issue a new “street legal” VIN or enable the existing VIN to be used.
New Jersey and Pennsylvania have processes in which you must produce before and after photographs, receipts for all modifications and replacement parts, as well as the original title, and submit the vehicle for an inspection, either by the State Police or a licensed Motorcycle Inspection Facility, in order to be able to get a new or reconstructed vehicle title. WA probably has a similar process.

A second route you can pursue is having the bike re-titled through title agencies that specialize in vehicles with lost titles. The have policies that enable you to re-title and register vehicles that are over 10 years old using a bill of sale by mail. You fill out the forms, send in the required documentation and fees and receive a new registration and license plates and possibly a new bike registration. I do not know if this will work for your situation, but it can't hurt to investigate.
I have included links to a few companies that specialize in this re-titling process below. Over the years we have known a few customers that have utilized services from these types of companies and they seemed very pleased with the ease and simplicity of the process.