Since around here the mono is not vintage eligible anyway, I did not need to stay drum and I converted to a front disc. Heard the older kits were not much good. I used a 2000 GasGas front wheel, caliper, hose and master cylinder all stock, that I kept for spares for my daughters bike. Used the TY Yamaha axle, made some spacers for bearing location and diameter from copper tubing and flat washers, changed disc mounting bolts to thinner button head allen screws, and made a caliper bracket that floats on the axle and takes torque rection via a slot around the original lug on the fork leg. All told, about 4 or 5 hours. Basic tools plus welding. Steel is heavy, but I could prototype it quicker, and it works so well I have never gotten around to making an aluminum bracket.

Huge difference. Not so much strong, although it is much stronger, but in predictability. I never knew if the TY woudl be good brakes, no brakes, or lockup brakes.

Arcing, cleaning, all sorts or things. I did find Vesrah japanese aftermarket shoes (Dennis Kirk here ins Minnesota anyway) was the best choice for me and softest. Then I changed to the disc and no more issues.

I may have posted pics and info in the Yam section some time ago. I have an article but my website is down.

pm me an email and I can send the article, pics, and bracket dimensions drawing.

My TY250 is a twin shock so may be different. I found that I had to rebend the lever because it did not have enough travel before hitting the throttle tube. Probably because of cable stretch or bracket flex, but bending the tip away allowed more travel and improved braking.

You can see it in the attached pic. No, that was not from a fall, it is an intentional bend.

what year yz125 brake plate do i need to find? Presumably end of the 70s early 80S?