Hi again, what is the front brake like when new/properly set up? I have scuffed drum with emery cloth, chalked and removed high spots on shoes all afternoon, centred brake before tightening wheel spindle etc, adjusted cam lever, adjusted cable bottom and top. Will this bike ever nose wheelie or am I expecting too much? It doesn't really feel like it would stop me on a steep downhill. Frustrated. I probably need a new cable? Should it have the same stopping power as my mate's mid 80s mono ty250?

If everything is perfect it will be no better or worse than a 1985 TY drum-front-brake mono was when it was new.

If you had to take lining material off to get full contact, it means that the drum is probably a bit big in diameter and you probably now need to pack out the pivot ends of the shoes to minimise the cam angle.

If the drum surface is grooved or uneven they will never work well no matter what you do.

It's normal practice with people wanting the best front drum brake they can get to machine the drum smooth, have oversize high friction lining material attached to the shoes and then machine the shoes down to match the diameter of the drum, using the backing plate to hold them in position in the lathe

My TY175 had a poor performing front brake. I messed around with it for some time and could not get it to improve. I finally ditched the aftermarket brake cable I bought and went with a Yamaha OEM brake cable and the brake works so much better.

Thanks guys. I suspected as much.

If the 250 has the same set up as the 175 then there is a fundamental flaw in the design.

The abutment for the outer cable also takes the cable through an angle; you can feel this tube bending when you apply the brake thus weakening the braking effort.

If I remember correctly the brakeplate from the motocrosser fits and solves that problem.

Nose wheelies do not come from just squeezing the front brake lever. If that is how you try a nose wheelie you may want to consider traial basics again. The front brake is merely an aid helping to lift the rear end one you properly start the  nose wheelie compression. A proper nose wheelie is done the same as a straight up wheelie, no not by twisting the throttle!!. 

I had the same problem with my TY250A.  Did all the things as above with the same result you had.  I finally tracked it down to the lever actually bottoming against the throttle tube and grip.  With the lever removed from the bike and in a vice, I heated up and bent the lever to be farther from the bar.  I got a little extreme because I wanted to be able to use 2 fingers on the brake and have have the lever come out before the other 2 fingers.   It looks strange but works great.  On any surface, other than paved, I can lock the front wheel.

On 16/03/2017 at 4:52 AM, evoalien said:

Nose wheelies do not come from just squeezing the front brake lever. If that is how you try a nose wheelie you may want to consider traial basics again. The front brake is merely an aid helping to lift the rear end one you properly start the  nose wheelie compression. A proper nose wheelie is done the same as a straight up wheelie, no not by twisting the throttle!!. 

Thanks for that. I will consider trials basics very shortly as I have only just got my bike set to go.