Thanks for your comments. I went ahead and tried to check the things you mentioned.
charlie55 wrote:- Warped disk rotor (highly unlikely in a new scoot). Get the front wheel off the ground, watch the rotor from dead ahead as you rotate the wheel. If it appears to be wobbly in relation to the wheel itself, then it's warped. You actually need to measure this type of problem with a run-out gauge to be sure.
While my garage equipment is pretty limited to stuff to do with bicycles... what I did was I tilted the scooter back on the center stand and propped it up with some scrap wood. I set my phone camera under the front wheel and recorded while giving the wheel a few revolutions at several different speeds. No noticable wobble on either the wheel or the disc, so I guess that's good. Since I don't have one of these run-out gauges that's about as far as I'm going to get on my own. (Didn't bother to upload this video as there's not much to see.)
- Debris embedded in the brake pads. Sometimes you can pick up small bits of gravel or other road crud that gets stuck in the brake pads. Check your disk rotor to see if there's a noticeable score (scratch) running around the entire circumference of either the outer or inner (you might need a mirror for this) face of the rotor.
The rotor looks a little scraped up, but the scraping is evenly distributed and I don't see any scour marks or rings that stand out. Nothing I wouldn't expect to see on a bicycle equivalent.
I tried shining a flashlight through the caliper straight between the pads and the rotor, to see if the photons were blocked at any point. I did not notice any blockage or scraping near the bottom of the pads, but this actually turned out not to be a very good test because I think the arc of the caliper housing may be blocking the upper portion of the pads anyway. It's hard to know exactly what I'm seeing down there because of the fork, rim, etc. all being in the way.
What I do see, though, is a bit of yellow coating, like paint maybe, which has scraped either onto or off of the outer bevels of the rotor. Some of it was loose and I was able to brush it off with my hand, but there was not a lot of it. Incidentally, my disc brake lock is yellow, but I think it's highly unlikely that it transferred paint only to the edge of the rotor like that.
My best guess is that the top of rotor is actually scraping the roof of the brake assy somehow, and I wonder if something is out of whack up where the pads mount. However, taking the weight off the front wheel doesn't seem to make it any better.
My number two guess is that while I was in Walmart, someone was screwing with my scoot and tried to pull it away with the disc lock on it, and in doing so, jacked something up with the front wheel somehow. If they DID, I certainly didn't notice anything else weird other than the scoot being parked a lot farther back than I remember. (Maybe it's just me.)
Or maybe it's just stuff settling into place, as it IS a brand new scoot.
Now, that "pffft-whoosh" sound you get when only rotating the rear wheel - that has me bugged too. I'm neither a Buddy nor 2-stroke owner, but it sounds to me as if your rear wheel is turning your engine over and thus moving the piston up and down. That shouldn't be happening with a CVT transmission because the clutch should be disengaged. Maybe this is normal for a Buddy 50, so I'll defer to those having more knowledge than I in this case.''
Yeah, I don't know much about these things myself, obviously, but I'm less worried about the rear at this point. Whatever it is, it's probably normal, and I was just distracted and confused trying to figure out where the scraping noise was coming from.
The brakes seem to be working fine. I checked where the hose attaches to the brake assy, and there isn't any apparent leakage.
At this point I've got a little less than 100 miles left until I'm due for my first scheduled maintenance at 200 miles. I'm thinking if this is not a big problem, I can just bring it up then. If it's just a pad rubbing, I'm guessing it will wear down by then but who knows...
