Tire issue ? or Not ? Question

[you you]

I would recommend any one riding a PCX to watch out on uneven road surface, be very careful, keep straight up.

Just no arguing with that

[easyrider]

Maybe one of the two pistons operated by the right/front brake is siezed or sticking?

I was wondering about a master cylinder problem .... is that what the reservoirs are called on a motorbike?

That very well could be.. I do think that is where the problem lies, however I also think that this is common with this bike. Might just be a quirk with this scooter as "D" above had a similar concern.The pistons both operate differently in that one pressurizes and then when hits resistance the other piston pops out and pressurizes and they both then add the force equally to the rotor supposedly ??. if you get what I mean.When CBS kicks in I believe just the center piston pressurizes and the braking on the rotor is singular hence more consistent wheras the double piston may throw an imbalance at first activation. Keep in mind this only happens upon quick braking but OK on a coast or gentle application with me anyway.

[kramnala58]

Maybe one of the two pistons operated by the right/front brake is siezed or sticking?

I was wondering about a master cylinder problem .... is that what the reservoirs are called on a motorbike?

That very well could be.. I do think that is where the problem lies, however I also think that this is common with this bike. Might just be a quirk with this scooter as "D" above had a similar concern.The pistons both operate differently in that one pressurizes and then when hits resistance the other piston pops out and pressurizes and they both then add the force equally to the rotor supposedly ??. if you get what I mean.When CBS kicks in I believe just the center piston pressurizes and the braking on the rotor is singular hence more consistent wheras the double piston may throw an imbalance at first activation. Keep in mind this only happens upon quick braking but OK on a coast or gentle application with me anyway.

Try disconnecting the brakes and stopping by using only the soles of your shoes. If the problem doesn't recur, then you know it is the brakes.

[PCX150Rider]

Please keep going until you find out what the problem finally is and let us know what you came up with as a solution. Inquiring minds need to know. . .

Sorry I can't opt in and try anything to duplicate your experiment because I won't have my PCX until the end of summer. My current scooter (Genuine Roughhouse) has a disc brake up front and drum in the rear independently actuated. That being said I never experienced anything like what you are talking about on it. I don't think the tires were ever perfectly balanced but no big deal there. . .

[PCX150Rider]

On another note if you don't feel safe riding it just bring it to a dealer mechanic and see if they can figure it out. Safety first!

I've had a caliper get out of wack on a Jeep so that when I hit the brakes the front end pulled to one side. I brought it to a mechanic and he said the caliper showed signs of corrosion and was seizing so it had to be replaced. It solved the problem. It was causing the rotor to heat up too but it didn't get damaged. I didn't drive it much when it started acting up.

Corrosion also can effect sensors in ABS brakes over time as well. Salt on roads doesn't help.

[maddiedog]

That sounds to me like something loose in your steering head bearing, where the forks meet the frame.

Have someone sit on the PCX to hold it up, with their arms holding the seat next to them. Stand in front of the PCX, and put your feet on either side of the front wheel to try to hold it in place. Grab the handlebars, and try to turn the front wheel back and forth. Does the wheel move exactly the same, or is there any slack in the movement? The wheel should move perfectly with the handlebars, with no slop whatsoever.