brakes cause vibrations when not applied?

[6ftMach1Girl]

Let me start with disclaimer that I am definitely not a mechanic. But I do try to understand things.

After I got my PCX 150 back from my first service at 600 miles, I started to notice a slight vibration when I would first twist the throttle as I exited my driveway. Would usually go away after the scoot got warmed up. I thought maybe this was the "chatter" some folks mentioned on the forum. I have been trying to make an effort to warm it up more before I ride, but lately the "chatter" has been getting to be more of a violent shudder, and continues to occur for a while after I start riding, every time I hit a particular spot when twisting the throttle.

So yesterday I dropped it off at local dealer for 2500 mile check (I have dealer warranty) and mentioned the problem. I thought maybe it was a belt or transmission issue, which I thought would be covered. Instead, they told me it was something with the brakes (being too tight or something). They say they bled them. Even though the brakes were never applied when the problem did occur. And my bill is only $170 and some change.

As an aside, the technician did tighten my parking brake last time I had it in to get my luggage rack installed, as the brake no longer held the bike. He said the brakes were fine. And it was vibrating before I took it in for that visit.

Does this sound right? Please advise. Very appreciative!

[gn2]

Its normal for there to be some judder when cold.
This is due to the transmission system getting worn and dusty.
The simplest solution is to ride it long and hard to blow the dust out.
Take the parking brake off, thing's right up there with the chocolate fireguard and the trap door for a canoe.

[6ftMach1Girl]

Its normal for there to be some judder when cold.
This is due to the transmission system getting worn and dusty.
The simplest solution is to ride it long and hard to blow the dust out.
Take the parking brake off, thing's right up there with the chocolate fireguard and the trap door for a canoe.

Yes - the parking brake is off . Thank you.

Should the tranny be that worn at only 2500 miles? "Some judder" is fine with me, but this was teeth-rattling.

[gn2]

Could be glazed clutch shoes.

[6ftMach1Girl]

Well, maybe it was brakes? Seems to be back to normal - no earth-shattering vibrations on the way home from the shop. Mechanic said when he went to spin the front wheel, it wouldn't turn. So he said he bled the air out and it turned fine and no shuddering. Also confessed he just learned that the PCX has combi brake.

[pcx man]

I started to notice a slight vibration when I would first twist the throttle when its cold on the first few stop and goes. After that its ok. Mine has gotten worse over time as I have 7600 miles. I did take the belt cover off and blow out all the dust as I checked the belt. That seem to fix it for a time. I also got rid of the vibration when I changed my rear tire. I used a impact to tighten the rear wheel nut. I think this knocked the dust out of the rear clutch asy.

[maddiedog]

Well, maybe it was brakes? Seems to be back to normal - no earth-shattering vibrations on the way home from the shop. Mechanic said when he went to spin the front wheel, it wouldn't turn. So he said he bled the air out and it turned fine and no shuddering. Also confessed he just learned that the PCX has combi brake.

I don't see how that's possible. If the front wheel wouldn't turn, the brakes were binding, the disc is bent, or the bearings were bad, none of which are solved by bleeding the brake. Bleeding the brakes solves the symptom of brakes being too soft and not functioning. I'm entirely unsure why he did that.

If it's back to normal, I wouldn't complain, but I also wouldn't go back to that shop.

[gn2]

Maybe they cleaned up a sticky front caliper, but if the brake was binding enough to cause transmission judder you would have definitely noticed it when pushing the scooter around.

[adambee]

Ha! I've been having a very similar problem to 6ftMach1Girl and pcx man-- I should have checked the forum more before I posted!

I am going to try being more decisive on starts (although I've tried that more recently and it doesn't seem to help a ton), and I'll also get a can of air and blow off everything around the transmission and belt.

If those don't work, I'll take it to the shop and see if they can fix it. Seems like it shouldn't be happening with only 1800 miles on my scoot, but maybe I've already glazed up the shoes through too many gentle starts.

[6ftMach1Girl]

Personally I prefer to pull out briskly when the light turns green. I don't think that had much to do with it in my case.