Piston sizing on my Yamaha Enduro DT 100?

I got a 1974/75 Yamaha Enduro 100 for free, and for good reason. I know most people will probably just tell me to throw the bike out and save the trouble. Its in bad shape but I dont have a bike and I want to rebuild it since I know absolutely nothing about engines or motorcycles. Long story short I took the engine out because the kick start seemed jammed. The kick start gear is engaging so it wasnt that.

Turns out the piston was seized and rusted to the cylinder. I got the piston out and know that I need to take the cylinder to a machine shop and have the cylinder re bored a little larger, mostly to get the rust out and make it smooth again. Not sure what size piston I need tho, because I am unsure of the piston size that I have now. I was going to have the shop just resize the cylinder to the largest piston size available for this engine.

The information I do have is that there seems to be a 9 (could be a 6) on the inside with an upside down T above it. There are two other number on the inside as well. One is in large easier to read print: 65801 and the other is further in on the inside of the piston: 0112. The outside has ART printed near where the pin goes to connect the piston to the crank arm. Any information would be appreciated, and I apologize in advance if some of the vernacular I used to describe the piston is incorrect. Thanks

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now