Disc brake rattle question - YY250T

[Shadowfire]

I recently purchased a 2nd hand 2014 Jonway YY250T scooter with 450 miles which didn't turn over. Here's the bucket list so far:

* recharged battery (engine now spins but still won't startt)
* stripped off the seat and most of the plastics
* cleaned out the carb (it fired up and ran). replaced a ton of clamps on the carb.
* changed the Oil and cleaned the screen (old oil was black, screen was actually clean)
* changed the antifreeze (old stuff was pale yellow) with 50/50 prestone premix
* changed the tranny fluid (looked like it had a lot of metal particles suspended in it)
* restart the bike to bleed the heating system... leaking antifreeze @ 5000 rpm. Coming out of the water pump feed into the cylinder at the connection. Clamp was broken, someone had put Teflon tape (!) inside the connection instead of replacing the clamp- replaced both the feed/return hose clamps here, since I don't want problems.
* exhaust was leaking at the cylinder head connection and muffler was starting to show rust. ordered new gaskets, sanded down and repainted the muffler with high temp primer/paint, ordered stainless steel bolts/lock washers/washers for the heat shield
* waiting for a USB charger port and some electronic-safe silicone. NONE of the connectors I've seen are weatherproof. Going to silicone, shrinkwrap, and zip tie it all together.
* trip meter reset button is impossibly hard to activate. gotta get in there and see what's going on, hopefully some lithium grease is all that's needed.
* ordered a top end kit (piston/cylinder/rings/gaskets) in case there's no power or if the next oil change is contaminated.
* surprisingly, the existing fuel line was DOT certified, so I didn't end up replacing it.

Anyways, I haven't actually driven it around yet, but when I revved it up (prior to removing the muffler) on the center stand to about 6000 rpm I can hear some sort of metal rattling which seems to be coming from the rear disc brake. Now the caliper itself seems to be bolted on good and tight, and the disc itself has no loose screws. I seem to be able to rock it side to side a tiny bit, and the front caliper has the same amount of side-to-side play. The reason I'm asking is, I'm not sure if this is OK or not. I'm leaning towards it just being engine vibration rattling the calipers around. They are definitely on there good and don't budge at all if I try and move them up/down (like they would be forced to when braking). I do not hear any rattling below 6000 rpm. Is the rattling a cause for concern? Or am I mis-diagnosing this?

Anyways, this bike has been a real eye opener. My other bike, a 50CC Kymco Cobra Racer, has given me 12 years of trouble-free service, with only tires, batteries, valve stems, and belts being replaced (along with a carb cleaning when it sat too long).

[rks]

I have a 150cc Jonway with the same rattle you describe. It has been that way since brand new, and is definitely the rear disc brake. I think you'll find that it only does it under heavier throttle settings, as in pulling a hill, and not when just cruising along at steady pace. I've learned to live with it, and after 5800 miles, the rattle is no better or worse.....still running original pads with lots of life left in them, brake works and will stop the scooter fine........but I sure miss the old, trouble free, cable operated, drum brakes, that came on all bikes a few decades ago. I really don't need disc brakes to stop a 250 pound scooter.

[bull]

btw. Welcome to the forum, from one newb to another

As rks suggests the rattling is not a great concern so long as you monitor the pad pins for wear. If they get worn too thin, they could snap under high stopping force.

As to the oil being "black" I am rebuilding a Diamo Velux 250cc engine (Helix clone) and the oil was extremely black as yours, but the only internal damage was from poor service techniques.

The coolant you mention is something I am going to change. The water pump impeller and cover had excessive corrosion and he was using the green coolant. I may replace it with the gold coolant spec'd by Audi as it protects really great. Also the clamps are the screw band clamp, I will replace them with "spring steel" band clamps that continuously tighten themselves.

the differential in this one is built too tight and requires too much effort to hand rotate, thinking of increasing the gasket thickness to about 0.030" to open it up just a little and reduce friction.

[Shadowfire]

Thanks for the replies.

Something I didn't check, that I noticed today (and that I'll have to check again when I have the muffler back on) is the springs that enclose the hydraulic brake cable.

[Shadowfire]

* Replaced brake fluid, front and back.
* Pulled off front plastics and cringed at the wiring. The "radio" control panel has a flat flex cable, to which they've soldered wires coming front the main unit. Wires have been terminated in a wire cap. Lubricated the tripmeter reset switch, but can't really check it right now.
* Attempted to install stainless bolts into muffler heat shield, but the holes in the heat shield are in the wrong location. Brought out dremel to expand them to the right area. Had to trim off part of the heat shield with steel shears. It fits well on the muffler now.
*Put exhaust adapter pipe back in with new gaskets. When trying to put muffler back on, broke one of the bolts going to the engine while trying to torque down to 36 ft-lbs per the Reflex manual. Putting in another order at McMaster-Carr for drill bits, center punch, replacement bolts / washers / lockwashers.

[Technorick]

Shadowfire
Wow, what a laundry list of things you have done! I just received my new Jonway YY 250-T2 last week. When I opened up the front plate to expose the wiring harness that leads to the instrument panel and saw the ribbon cable for the radio I LOL.. I wrapped mine in a plastic bag then sprayed some self expanding window foam around it to seal and hold it in place!

Then I discovered the spedo cable was not attached... And the blinker wires were reversed.. I used an entire tube of clear silicone on the bike sealing the back sides of the white plastic connectors and the screw clips to plastic parts. Added about ten wire ties in there... Found a spare plug with green and black wires that I suspect is the other end of another spare I found down on the frame with the same color wires...
Up at the blinker switch and the light switch I used small amounts of dielectric grease to seal the backs of those switches as it appears based on the design, those will be exposed due to opening for the clutch handle.. My My housing plastics dont seat well between the front and back of the instrument cluster so I used black silicone to seal that from the elements too. My plastic blinker switch feels almost like its designed to break after normal use....I would like to replace it with a better stronger part than that...

Have only run it for a while in the garage (six ft of snow here) but I think I have a fuel tank float or senor problem too...

I'm thinking of possibly tapping into the radiator sensor and adding a digital thermo gauge, and am planning to add a digital DC voltage monitor to monitor batter charge...

Good luck to you.

[Shadowfire]

Yeah, the wiring is something else on these bikes, and probably the weakest link. I'm waiting for a warmer day to work on the bike/remove the remnants of the bolt, and install the USB charger/voltmeter that I bought off of Amazon. (I'm going to be sealing all the connectors with ASI388 and heatshrink.)

It turns out that while the Reflex manual specifies 36 ft-lbs for the muffler mount bolts, the YY250T has M8-1.25 bolts, which according to http://www.imperialsupplies.com/pdf/...rqueCharts.pdf
should be torqued to a max of 18.75 ft-lbs. Apparently the reflex had larger diameter bolts there. From now on, I'm not going to rely solely on the manual for torque settings.

I've already exchanged the antifreeze and run the engine for 45 minutes. Burped the lines for the first and second warmup, then closed the radiator cap, and had to add antifreeze the next two warmups - now its not getting low in the overflow tank, so everything seems ok there.

On its center stand, the bike will not get above 50% temp unless I run it constantly over 5000RPM. As soon as I ease off the throttle, it cools down within a minute. It seems that the radiator fan by itself isn't adequate for that rpm, but I expect you'd be going at least 40mph by that time.

[Shadowfire]

Just the act of moving around the instrument cluster cause one of the bullet connectors to become flaky, and the instrument backlighting is now off. It comes back on as long as I press on the connector.

Fixing the connectors the right way would cost me almost $300.
(http://www.ebay.com/itm/DELPHI-WEATH...1491ee&vxp=mtr)

Since I can't really pony up for the kit at the moment, going to proceed with the original plan, but replace all the bullet connectors.

[Shadowfire]

Update:
Took off the instrument cluster. Zip tied a barrier strip to the back of the cluster, and ran all the grounds and DC power distribution to it with ring terminals. There were 13 wires tied together for ground, and 7 wires for power. The wiring is much, much neater now.

The flakiness ended up being due to a 6-position connector, on the ground wire. Popped the pin out, cleaned it with contact cleaner, compressed the clamping edges, and reinstalled it. Reworking the instrument cluster wiring also fixed the tachometer, which was going wonky at over 6K rpms.

All the connectors have been backfilled with AS388 silicone, and I have started the process of attaching all the plastic back onto the bike. Tomorrow should be over 40 degrees, and I will probably take a spin around the block to check everything out. First I have to replace the seat bolts (which are bent) and the main fuseholder with a blade fuse.

[Shadowfire]

So, finally put everything back together. Installed the DVM/USB charger, and hooked it up to the radio power line (which is switched on/off with the ignition key). Replaced seat bolts (bent), replaced grab bar bolts (bent and threads damaged). Replaced the "main" glass fuse with a blade-style fuse holder and fuse.

One of the rear tail lights was out. Replaced both of them with LED lamps. The front tire had a leak. Traced it to the valve core, replaced both valve cores. I can smell gas some times when I come to a stop, it seems to be coming from the gas cap, will replace that tomorrow. The suspension was horrendously hard, sprayed all the shocks with WD40 Lithium grease, and it got MUCH better. Took it on the highway for 1 exit... got it up to an indicated 85mph, but it honestly felt like 70ish (no gps on it just yet).

When re-assembling the bike, couldn't get the plastics on the front to line up correctly (center floor mat). Some of the plastic threads in the body work have been pre-stripped by the factory. Replaced a missing nut/bolt holding the plastic down by the radiator. There are two screws on each side near the passenger foot pegs, which had log wood screws in them, which I didn't replace. There is a nut welded to the frame, however the screw was too small for it. A proper diameter screw for that nut, is too wide for the holes in the body plastics. Additionally, I found two of the screw locking tabs on the floor, but never found the plastic attachment area they belong to. There are some rattles and a squeak from the right side of the windshield. (I replaced a ton of fasteners on the bike).

The gas gauge is way, way too sensitive. The act of braking or accelerating causes it to change. It's not an engine voltage phenomenon, either (I have a DVM on my dash now). I can see it wavering up and down when I come to a stop (and the gas is sloshing around inside the tank).

[Shadowfire]

So, having driven it around for a bit now, there's only a few things left to consider.
1. The speedometer is, of course, wildly optimistic. I had it pegged at 85 on a stretch of highway but I'm sure I wasn't doing more than 70. Engine was still running @ 5500rpm. I weigh 250lbs, so it probably isn't going to take me much faster than that unless I'm going downhill. The mileage travelled seemed OK. Going to be putting a GPS on it soon.
2. Related to the speedometer, the trip reset button is just craptastic, requires a ton of force, and doesn't really reset all that well (this even after I sprayed the mechanism with Lithium grease).
3. There are plastic shaking noises, and the windshield can squeak due to engine vibration. I haven't decided yet if I want to live with the plastics squeaking or if I want to spend another 6-8 hours tearing the plastics down and replacing fasteners.

[Shadowfire]

OK... took a turn a little too fast last week (still getting used to the bike.. I was turning at an intersection) and slid on the sand at the edge of the road, and dropped the bike at around 10mph. :( $150 for windshield and plastics.


I picked up a Bluetooth transmitter, ripped out the PCB, desoldered the USB and power jacks, and installed it internally on my TomTom. The Bluetooth PCB is powered from the TomTom's USB port instead of its battery, so it won't drain it. Also got a Bluetooth headset which installed quite easily into my helmet. I still haven't finalized how I'm going to get the GPS where I want it. There's no mounting points above the instrument cluster, I may end up gluing a small platform there for it.


I also ordered some Plastifix, since there were a bunch of threads that came pre-stripped on the plastics. I'll post next week to let you know how it pans out. I'm also using Weld-On 4 for repair of cracks/broken pieces. Externally it doesn't look that bad except for some scratches on the side of the front fairing (where it dropped on the snowbank) but I discovered several plastic tabs were broken when I stripped the plastics off.


I finally received the two 35W HID lamps. My first step was to replace the old lamps (it was fairly straightforward, and the HID kit came with the proper lamp backplates). Finding a space for the ballasts was less straightforward; I ended up using silicone to attach them to the area between the headlights, then modifying the existing harness in the fairing.


Upon firing up the bike, however, the lights would flicker at idle. It would go away once revved, but I took a look at the wiring diagram. The headlights are powered by the rectified regulated power rail, not the battery. I know that it has a 3-phase generator, and I suspected that the voltage was dropping far enough between phases to have the lights go out. I thought a bit about the problem and came up with 3 possible solutions:


1. Put a diode/large capacitor in front of each ballast. Unfortunately they are 35W (almost 3 amps each) systems and it would require a very large capacitor and each diode would also have to dissipate and additional 2W of heat, and would need weatherproofing.
2. Run a new circuit off the battery to power the headlights. The battery should not drop far enough to have the lights cut out during idle. The drawback here is that the battery ("blocking") diode now has to deliver an additional 6 amps for the headlight circuit.
3. Install a 2nd battery and charging diode for driving the headlights. I would need to use some of the limited space under the seat, and I wasn't exactly thrilled with the prospect of having to maintain two batteries, but it would prevent additional thermal load on the blocking diode.


I opted for option #2, purchasing an additional two automotive relays, an inline 10A fuse, and building up a wiring harness to run parallel to the existing wiring harness for the circuit to the battery. The highbeam/lowbeam switch now activates either the high or low relay, which connects the HID lights to the battery circuit. The lights no longer flicker at idle. Only time will tell if the diode can handle the extra current; I have no idea what power it is rated for (or is passing), but I'm probably naïve to think that there's 6A of headway engineered into this thing.


Anyways, pulled off the handlebars, and the flange bolt through the stem is bent by about 3-4 degrees... off to Fastenal again tomorrow to replace it. The handlebars that I received were the wrong ones, but it turns out that the existing handlebars aren't bent at all, it was an optical illusion due to the fact that the factory couldn't be assed to square up their work when welding the front fairing mounts to the frame (which also explains why the panels didn't line up when I originally reinstalled them).