Dome Light Repair

[Captain Obvious]

I know just enough about the casting process to be dangerous. My understanding goes something like this... To do it "acceptably", you can watch some U-tube videos and read some websites. To do it "really well", you need to know what you're really doing.

From my limited experience, I would predict two stumbling block areas:

1) Getting the large flat surface to cast properly without wavy-ness. Might be able to make a support "box" that surrounds the mold for additional support.
2) Getting the translucence and color of the casting resin right. I don't think this would be too difficult, but it would take some experimentation.

As for your carbs... I've been known to put the smoke back into cycle carbs from time to time. Since I worked my carbs, my bike starts, idles, and runs perfect. Is there something specific causing problems?

[heyitsrama]

On 3/5/2021 at 7:02 PM, Captain Obvious said:

I know just enough about the casting process to be dangerous. My understanding goes something like this... To do it "acceptably", you can watch some U-tube videos and read some websites. To do it "really well", you need to know what you're really doing.

From my limited experience, I would predict two stumbling block areas:

1) Getting the large flat surface to cast properly without wavy-ness. Might be able to make a support "box" that surrounds the mold for additional support.
2) Getting the translucence and color of the casting resin right. I don't think this would be too difficult, but it would take some experimentation.

As for your carbs... I've been known to put the smoke back into cycle carbs from time to time. Since I worked my carbs, my bike starts, idles, and runs perfect. Is there something specific causing problems?

I was thinking the hood of a car might be a good place to start, it’s large enough that’s it’s gonna be a pain in the arse if you don’t finish ha! First you would have to make a negative mold of the current hood, then you would come in and lay new material to great the new hood inside that mold. Seems straightforward.

As far as the translucency goes, don't you have to coat carbon fiber or it starts to degrade? I see "cloudy" carbon fiber, and its almost always when it's not painted over. Seems like that it would not be TOO big of a problem. Maybe the tech was just old when those parts were made and modern resins are more resilient to cloudyness.
 

Ah the bike, I got it a little closer yesterday, I was able to get some what of an idle, but I found that the battery died while I was running it, so I started digging into the alternator circuit and found two questionable wires that I replaced. The next issue is the tachometer, which need to be fixed because it’s “zeroed” at 1900 RPM, I can’t really tune it because I can’t see where is is. Parts have been ordered, so back to the Z while we wait

The replacement dome switch is here. I attempted to install it and it works well. There is an issue that I can foresee which is how loose the white plastic is inside the body, but I’m not sure how loose they are from factory. It might rattle around when driving. Also the copper wires from the switch can’t be soldered to the aluminum parts of the body. Maybe some type of glue can be used? Or a copper rivet?

 

Edited March 9, 2021 by heyitsrama

[Captain Obvious]

About the casting process, I was referring to small stuff like the lens for your dome light. Not big layup stuff like a carbon fiber hood. I was thinking that you might be able to copy your dome light lens before you break it.      I've done a little bit of small stuff, but don't think I would ever attempt something like a hood.

The original switch button contacts the lens at all times which helps squelch rattles. It sounds like your new switch's push button (even with the rubber seal installed) is shorter than the original button. Maybe you could put a small rubber button in between the two to take up the gap.

And about the soldering... I'm sure it's not aluminum. Not sure what it IS, but it's NOT aluminum. Either nickel plated brass (which should accept solder easily), or steel (either chrome plated or stainless). Are the metal parts magnetic? I think I've got a dome lamp around here that was damaged. I don't remember what "damaged" means though. I'll have to see if I can find that thing.

And good luck with the bike. What carbs do they run on that? I assume it's either Mikuni or Hitachi.

[heyitsrama]

AHHH! I see what you mean by the casting process. Yeah that would be pretty swell. I could have an extra dome light for when this one fails.... (hopefully never)

Common Capt. you know you wanna take that old heavy hood off and get some carbon goodness on there 🙂

I used 3mm hardware and some eye terminals to make contact with the “plated” material. I also added the rubber washer that came with the switch and it’s pretty snug now. Tested it out in the car and it works. Just waiting on the LEDs. I went back and added some heat shrink near the terminals just for safety.

 

Keihin carbs on this cb500 actually. It’s not too bad to work on. Dialing in the SU kinda taught me how they work, at least how to approach it. Need more stuff to tinker with, this project was supposed to take longer. 

[Captain Obvious]

Dome light looks good. Hope you like the LED when it comes in.

So I have no experience with Keihlin, but I'm assuming the basic concept is the same for all of them. Just pay attention to the details and make sure everything is clean, clean, clean.

And I can do without the carbon fiber goodness.  Haha!!  

[HusseinHolland]

On 3/2/2021 at 3:26 AM, heyitsrama said:

This might fit the bill, i dont need 5 of them though. https://www.amazon.com/mxuteuk-Waterproof-Push-Button-Motorcycle-MXU-kp-107/dp/B07Z4BDXLX/ref=sr_1_20?dchild=1&keywords=push+button+toggle+switch&qid=1614673411&sr=8-20#customerReviews

Thank you for the link. The eBay link is dead. Seems a waste too buy 5, but considering the $$$ pricing for a new lamp, $10 for a switch ain't so bad. I did find a listing for 2 for $8, but 5 for 10 is such a better deal 🤪 I'll have to find other uses for the extras.

I guess this is a fairly common failure. With the attention to detail & Japanese desire for precision I'm kinda surprised. I can't imagine it was used that often. I was going to disassemble the switch & clean up the contacts, but that doesn't seem worth the time.

Edited May 1, 2023 by HusseinHolland

[heyitsrama]

I searched for "water proof push button switch", I ruined one of the 5 when I was fixing this, so might be nice to have a few spare...

Its pretty hard to open the OEM switch without the plastics breaking, I find it to be too brittle, there is a spring and some sort of rotating dial/mechanism in there. I would be surprised if they can be repaired... I guess its a switch, thin metal, when it weathers and builds resistance its going to heat up and melt.

https://www.ebay.com/itm/323539395923?hash=item4b54736553:g:Q8wAAOSw8Ehb49~s&amdata=enc%3AAQAIAAAA0EZ442YEWVNV2hOaEEz5Gnxia76JJ6I6kY34KBMUMNHDsP6tz2gOh%2BAf0iPPVVIejs9%2FrhLedyvMf3hh9aThRcHU75wUaY8UCsZBcgIioyTUfi%2Fy72VdBqoKzsSrDjzYkLWsOhrKvSA8bccwn17DDATenZis8COZwZYaUbgPsLjT%2BizXifWSPO8PQJrTszkzZeJ238GdaA1onX13HWOjzvJoOvHS0kO13BvB5DWpy8t9Y%2FMFS8PZPtRT6d2Wajfc1p0ZmXroMd8%2BnKT2mq94ZYU%3D|tkp%3ABk9SR-L4xN_6YQ

 

I should install the damn headliner and finish putting the interior together.

[HusseinHolland]

I removed the switch by drilling out the rivets. Looks like the contacts thru the rivets were bad. There was discoloration on both conductor tabs. I have to retest the switch with the cleaned contacts

aluminum rivets

contact design - open

contacts closed

if the continuity is good with the cleaned contact area I'll use brass screws instead of aluminum rivets

 

[HusseinHolland]

OK - so with mine, cleaning the contacts & replacing the rivets with brass screws has resolved the lack of contectivity.

 

circuit open

 

 

circuit closed