Author Topic: Overflow Sight Glass Replacement.  (Read 863 times)

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 3975
Overflow Sight Glass Replacement.
« on: January 02, 2019, 01:33:11 PM »
The sight glass on my overflow tank had more cracks than a plumbers convention. A mate had four spares that were in more or less the same condition yellowed and crazed. I was waiting for Motorworks to reopen and order a new preloved one and a few other bits and pieces. However I got bored between Christmas and New Year and decided to have a go at replacing it. The theory being if I stuffed it up I could borrow one off a mate until I could get a replacement.

I ended up milling one out of a piece of 25mm round clear acrylic using my drill press with cross slide vice and wood working router bits. I picked up a few clues of the local Trades Guild ( closed for Christmas) on how to mill acrylic, high speed is not required and to spray the job liberally with WD40. The WD40 stops the acrylic melting onto the router bit and the job. Once I had it milled down using the old one for measurements I cut the corners down filed the ends to achieve the rounded ends. As I didn't know what was under the old sight glass and how it was shaped I left the base flat. I did cut the internal channel for the sight. I then filed out any tool marks and sanded and polished it with a cotton mop on a 6" bench grinder and an 1/8" air grinder with a small mop attached.

I removed the old sight glass roughly with a mini disc cutter and a 1/4" burr grinder carefully. I found that the sight glass is recessed and fits over a projection molded into the tank. Once I had ground it down I was left with a rim of sight glass running around the projection. I ended up hot gluing a couple of old pieces of hacksaw blades to the side of the tank to prevent gouging the tank with the burr. I then held the blade against the tank while grinding to remove the curved ends. A bit of filing cleaned up the edges and then the hacksaw blades are easily removed and the glue can be removed using a finger nail or plastic scraper.

The back of the new sight was then milled out to 3mm fit the projection, leaving a 2.5mm lip all the way around. This was then polished until I was happy with it. I obtained some Selley's black polyeurethane sealant  Flexifix to attach it . I ran a small bead of sealant in the corner of the recess smothed it out with my finger to make it even and then attached it. I now have to wait another 10 hours for it to cure recommended 24 hour curing time. It was'nt that hard of a job but it did kill a bit of time and I'm happy with it. The pictures are'nt that good probably due to the sight glass being clear.

Happy New Year to all regards Martin.

* Sight Glass 1.png (35.89 kB . 768x576 - viewed 101 times)
* Sight Glass 2.png (29.1 kB . 768x576 - viewed 84 times)
* Sight Glass 3.png (54.48 kB . 768x576 - viewed 85 times)
* Sight Glass 4.png (44.53 kB . 768x576 - viewed 86 times)
* Sight Glass 5.png (52.29 kB . 768x576 - viewed 99 times)
* Sight Glass 6.png (26.68 kB . 432x576 - viewed 94 times)
* Sight Glass 7.png (52.98 kB . 768x576 - viewed 85 times)
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline natalena

  • ^ Proficient Motobricker
  • Posts: 458
Re: Overflow Sight Glass Replacement.
« Reply #1 on: January 02, 2019, 05:48:07 PM »
Well done. Looks like you had fun fabricating the part.
  • East of Joshua Tree
  • 1987 K75s #0919
On Holy Quest seeking Techron equivalent for splines.

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 3975
Re: Overflow Sight Glass Replacement.
« Reply #2 on: January 02, 2019, 07:40:15 PM »
It was fun but if I had to make them for a living I'd go broke. It killed a bit of time and probably saved $50.00 AU. :laughing-on-ground:
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline natalena

  • ^ Proficient Motobricker
  • Posts: 458
Re: Overflow Sight Glass Replacement.
« Reply #3 on: January 02, 2019, 09:30:43 PM »
I can relate to the time/cost relationship, as building wood Spearguns is a passion. Buddies have asked "you should build them for a business" to which I reply "what? And go bankrupt!"
  • East of Joshua Tree
  • 1987 K75s #0919
On Holy Quest seeking Techron equivalent for splines.

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 641
Re: Overflow Sight Glass Replacement.
« Reply #4 on: January 06, 2019, 11:49:42 AM »
A fine job, thanks for sharing your stuff.
  • Livingston, SW WI. USA-"With the good earth all around."
  • NEW 1995 K1100RS Red,1994 K75S Red,1985 GL1200A Goldwing Aspencade, dreaming of adding a sidecar to the mix in 2019
Doing “better than I deserve”

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