Strange noise on a de-restricted '07 people 50 2t

[blufx]

Only 3300 miles  the scooter.

Some of this content was copied from forum posts  I was asking in.

 I NEED YOUR HELP!

I have this noise sometimes.  Kinda like a mechanical rattle.  At first it was only on occasion. Now it's almost constant. When it happens, there's a big power loss. I noticed it before I installed the 70cc BBK, and it's still there. Sometimes, I can start off and I don't hear it. When that happens, I have plenty of power, but if it starts, power drops a lot. Early on, I thought it was coming from the transmission just behind the motor. I changed my mind on that. It seems to be emitting from the AC generator. There's only a few reasons an AC generator could possibly make noise like this in my thinking, but it's none of those. The fan cover is secure. The fan is too. All four screws are intact and tight. The flywheel is properly seated on the taper with the woodruff key in place. The magnetic pick up is secure. Nothing is touching or can touch anything else.

Below is some other stuff I've done to figure out what it could be.

 I've taken it all apart. Everything looks great. I replaced the belt. The variator weights have a very slight flat spot on them. I've seen a lot worse and not hear anything. I noticed I could start off holding the rear break and prevent the rattle. I pulled the rear wheel  expecting to find loose springs or something. Everything is just the way it's supposed to be.  I can't see it involving the final drive gears. If they made noise, it would be constant. I checked them anyway. There's no detectable wear on gears or bearings. Even with the final drive shaft sticking out of the bearing about 5 inches, there's like .04 - .06" movement or play on the opposite end.

 It has nothing to do with the brakes. Everything is perfect in there, but I removed the shoes and rode it. Still there.

 I can start the scooter, give it some gas to make it produce the noise. The wheels aren't turning yet, but touch the brake and instantly the motor speeds up and smooths out for the most part. It doesn't go away completely.

 Man, this is driving me nuts. Can it be electrical? Is somehow lighting the rear brake light making it go away? But above all, what in hell can be making the noise?

[CROSSBOLT]

I vote for one of the main bearing shells (outer race) spinning in the case. Could also be a defective ball separator in one of the main bearings.

Karl

[blufx]

I vote for one of the main bearing shells (outer race) spinning in the case. Could also be a defective ball separator in one of the main bearings.

Karl

How would touching the brake enough to light the brake light heal the bearings? I'd think if it were bearing noise, it would always be there.

[chaz35]

"There's no detectable wear on gears or bearings. Even with the final drive shaft sticking out of the bearing about 5 inches, there's like .04 - .06" movement or play on the opposite end."  Can you post a pic of this? or describe it a little better?  Are you referring to the shaft wheel is bolted to?  Does the wheel have any side to side play after installed and torqued down?

Is this the same scooter you had in Jan?, that had 8300k/ 5200 miles?, and now has 3300 miles?

[blufx]

"There's no detectable wear on gears or bearings. Even with the final drive shaft sticking out of the bearing about 5 inches, there's like .04 - .06" movement or play on the opposite end."  Can you post a pic of this? or describe it a little better?  Are you referring to the shaft wheel is bolted to?  Does the wheel have any side to side play after installed and torqued down?

Is this the same scooter you had in Jan?, that had 8300k/ 5200 miles?, and now has 3300 miles?

Yes, it's the very same scooter, except now I realize I was looking at kilometers and thought it was miles. My mistake. It didn't have as many miles as I thought.
No, I can't show a picture as it's together now, but you're right, I am talking about the main shaft that drives the wheel. Without the wheel in place, there's VERY little free play at the opposite end, indicating there's little to no wear on the bearing.
On you last question., no, there's no side play. 

[chaz35]

If I understand what you said, the rear axle shaft moves .04 - .06' on the threaded end where the wheel attaches, right?

[blufx]

If I understand what you said, the rear axle shaft moves .04 - .06' on the threaded end where the wheel attaches, right?

Yes. With the shaft sticking out of the bearing about 5" and no wheel mounted, there's only about .04" movement. It's the only shaft on the scooter that could be sticking out of anything 5", well with exception of the crank. I hop4e you didn't think I may the two confused.

[chaz35]

My 05 People 50 2T with approx 9500k has absolutely no movement at the end of the final shaft with or without the rear wheel installed.  I checked the Kymco People 50 service manual and axle shaft runout service limit is 0.2mm.  Your 0.04" is approx 1.0mm so you appear to be over limit.  Also, under final drive trouble shooting it indicates "abnormal noise - worn, seized or chipped gears, worn bearing".

As I recall, when you apply the rear brake it helps with the noise?  If so, maybe brake shoes against the brake drum is taking some strain off the final drive bearings and gears which decreases the noise some, I don't know.  I think your final drive may be worn-out.

[blufx]

As I recall, when you apply the rear brake it helps with the noise?  If so, maybe brake shoes against the brake drum is taking some strain off the final drive bearings and gears which decreases the noise some, I don't know.  I think your final drive may be worn-out.

Please re-read what I've posted. It has nothing to do with the brakes. I've already gone through all this. I've even removed the brake shoes and still have the noise.  Why the focus on the rear wheel when the noise is emitting from the alternator?

[blufx]

My 05 People 50 2T with approx 9500k has absolutely no movement at the end of the final shaft with or without the rear wheel installed.  I checked the Kymco People 50 service manual and axle shaft runout service limit is 0.2mm.  Your 0.04" is approx 1.0mm so you appear to be over limit.  Also, under final drive trouble shooting it indicates "abnormal noise - worn, seized or chipped gears, worn bearing".

You're talking about shaft end play with it assembled. I said I was checking for bearing wear. With the shaft sticking out of bearing (alone) I got that movement. 

[CROSSBOLT]

I stick with my first vote and add that the bearings in the clutch could be doing the same thing. I read that this noise is simultaneous with power loss indicating the bike is moving letting the clutch off the hook. Splitting the case will reveal whether it is main bearings or not. Sideplay or runout of both alternator end and variator end of crank should validate splitting the case.

Karl

[chaz35]

"Yesterday, I noticed I could start off holding the rear break and prevent the rattle."  Does it still do this?

[blufx]

Does it still do this?

Next to last sentence in my first post. " I can start the scooter, give it some gas to make it produce the noise. The wheels aren't turning yet, but touch the brake and instantly the motor speeds up and smooths out for the most part. It doesn't go away completely."  Yes, this is the way it stands right now. Be sure to read the sentence just above that.

[CROSSBOLT]

Almost everyone with a modern scoot with a nearly horizontal cylinder has noted how smooth the idle is if no brakes are squeezed and how they vibrate when the rear brake is squeezed. I am guessing the rear brake is squeezed and wildly guessing it has something to do with a bad bearing "getting better" from the subsequent vibration. My vote is still one or both main bearings and the only way to start the verification is to get to each end of the crank and wiggle the exposed end up and down, forward and rearward: there should be NO movement.

Karl

[chaz35]

Have you pulled the stator and variator to expose the crankshaft on both ends and tested it for end play, the way CROSSBOLT has suggested?