Melted/cracked hole in headlight housing repair (with photos) Kymco Downtown 350

[mousejunks]

I really like the Kymco Downtown 350. It's reliable, highway capable, comfortable and two shopping bags can fit under the seat just like it's predecessor the Downtown 300i.

But there was one small niggle I noticed over the past few years (from removing the front cover for a coolant change for example) that didn't affect reliability or function, but was a design flaw in the headlight where heat from the 55W halogen bulb melted the plastic housing directly above it and caused it to crumble away, leaving a sizeable hole. This needed to be fixed.

[mousejunks]

1) Remove the front of the scooter - front black trim, windshield and meter cover.

[mousejunks]

2) Remove the headlight assembly.

This is all once piece joined with the left and right topside fairings. Undo the 2x 10mm centre nuts holding it to the metal frame. Pry the top of the fairings where it meets the black plastic around the gloveboxes, pry more then firmly pull the entire assembly forwards and diagonally down. All one piece and don't forget to disconnect the 2 headlight wire connectors.

[mousejunks]

3) Here's the hole in the plastic housing. It's directly above the bulb where the hot air rises when the bulb is running all the time (it can't be turned off when the scooter is running). The plastic is crumbly, cracked and has left a sizeable hole and the bits have already fallen to the bottom of the headlight case. The plastic around the hole is slightly cracked but mostly ok.

[mousejunks]

4) Close up photos of the melted/cracked hole.

[mousejunks]

5) Hole repaired with flyscreen and JB Weld Plastic Bonder which has excellent plastic bonding properties and cures in an hour. Photo shows 50% done, aiming to make it waterproof and dustproof, not neat.

[mousejunks]

6) Leave the JB weld for an hour to cure (30 minutes to sanding time but  wait 1 hour to be safe) and shine a light into the headlight to make sure there are no leaks. Otherwise mix up more JB weld and cover the holes.

Finally, put everything back together. Done.

[Ruffus]

..reasonable job Mouse, well done, txs for sharing...

Q: does this JB bond chemically (unseparable) with this headlight plastic no matter which material it is? ABS, PP, PPE,...

[mousejunks]

..reasonable job Mouse, well done, txs for sharing...

Q: does this JB bond chemically (unseparable) with this headlight plastic no matter which material it is? ABS, PP, PPE,...

For me the result was very good, it was impossible to peel away the JB weld from the headlight.

According to the reviews and official JB replies it doesn't work well on either PP, PE or ABS. I think it is more of a filler for plastics which I bought it for as other epoxies tend to be too runny. Alternatively I could've used Car Body Sealant (such as Sika 227) or melted a plastic panel over the hole.

[Iahawk]

nice job and thanks for the pics! Hard to believe Kymco would put out a scoot that melts its own headlight housing! Seems like water intrusion would be a problem for those who park outside or regularly ride in the rain.

[mousejunks]

nice job and thanks for the pics! Hard to believe Kymco would put out a scoot that melts its own headlight housing! Seems like water intrusion would be a problem for those who park outside or regularly ride in the rain.

The hole was somewhat protected from the weather with at least 3 layers - the windshield, windshield trim and body of the headlight so no direct exposure but it would be an issue long term due to dust and water.

Also, speaking of water intrusion, interestingly there are 4 vents on the headlight body to drain water and vent air.

[Ruffus]

Mulling this over once again:
Might have been an idea to create airholes to ventilate this headlights a little.
If it has been aired for years already, cannot harm anything, for its covered anyway.

[mousejunks]

Mulling this over once again:
Might have been an idea to create airholes to ventilate this headlights a little.
If it has been aired for years already, cannot harm anything, for its covered anyway.

I did think about that. That's why I used flyscreen in the repair because if the JB weld peels off, the flyscreen will remain and help keep out some water and debris.