Sight glass replacement woes

Well I thought I was doing great in finding some replacement sight glass pieces from an online retailer for cheap. They fit great look great, but... today I thought I saw a smudge or a crack on the one on my clutch master. Went to rub it with my thumb and the whole thing broke! I've got a rag wrapped around it to keep from dripping and so far so good. I scrambled on my lunch hour and bought some repair bits to replace the broken one and will let you know how it goes. I'm looking to use 3/4"/18mm mirrored glass discs with RTV sealant (after I remove the mirroring.)

Maybe it would just be easier to buy a 2nd hand master with clear glass? The ST11 uses a 14mm master, and there is a huge number of Hondas up to 2005 that use the same piston kit that would be a straight swap. I can certainly confirm that a VFR800 lever fits straight into the ST11 master. See the list here:

http://www.partzilla.com/parts/detail/honda/HP-22886-MB0-305.html

The links you have are for master cylinder rebuild kits and mine is fine in that regard. With my old original "glass" the plastic was faded, the new replacement ones were plastic and it appears the UV rays made it fragile in months. I'm not aware of any Honda master cylinders that have anything other than plastic for those windows. But I've seen other good articles about folks swapping the old sight glasses out with actual glass and RTV.

TerryS said:

Maybe it would just be easier to buy a 2nd hand master with clear glass? The ST11 uses a 14mm master, and there is a huge number of Hondas up to 2005 that use the same piston kit that would be a straight swap. I can certainly confirm that a VFR800 lever fits straight into the ST11 master. See the list here:

http://www.partzilla.com/parts/detail/honda/HP-22886-MB0-305.html

Click to expand...

I may have been less than clear, I was not suggesting you needed a new piston kit, but that list shows which other bikes would have a compatible master cylinder that you could use as a direct replacement for the ST master.


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http://www.ofrei.com/page_176.html

Appears that they have an $18 minimum order and that shipping might be in the $10 range for the lowest option.

From http://v4hondabbs.com/index.php?topic=501.msg1936#msg1936

Neal

TerryS said:

I may have been less than clear, I was not suggesting you needed a new piston kit, but that list shows which other bikes would have a compatible master cylinder that you could use as a direct replacement for the ST master.


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Click to expand...

Gotcha - good way to find a "where used" list!

I've seen that page before and probably would have done something like that if I had more time.

I went out a lunch since I needed some glass "now" and had no luck at the local jeweler's or glass shops. Hobby Lobby sells a 24 count of 3/4" glass mirror discs for $2.47 - don't forget to use your 40% off coupon. I was able to remove the backing and the mirror compound, and grind the glass down a bit for a frictionless fit. Some black rtv bedded it in place, then used some tape and a small band clamp to hold the glass in place. I added a bit more rtv this morning to build up a fillet. It doesn't look bad, and I'll report back on how it's holding up. I might be doing the brake master soon since that has the same plastic sight glass as the brake master had.

naedlaen said:

http://www.ofrei.com/page_176.html

Appears that they have an $18 minimum order and that shipping might be in the $10 range for the lowest option.

From http://v4hondabbs.com/index.php?topic=501.msg1936#msg1936

Neal

Click to expand...

Also, since the plain glass seats so far into the recess, I might add a second piece of glass flush with the front of the MC like original - if it's not too much of a pane that is...

Hey, an ST1100 with double glazing! Should help the resale value!


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TerryS said:

Hey, an ST1100 with double glazing! Should help the resale value!


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Click to expand...

Better insulatiion, too.

Definitely better insulation!

One thing that is nice is I can see directly into the reservoir now. So far so good and no leaks. Will tackle the brake master this weekend, and maybe the double layer belt and suspenders approach.

The clutch window has been in place for a week now and no problems. It's nice to be able to actually see into the reservoir, whereas the OEM style with the metal "shield" prevents that.

dkruitz said:

The clutch window has been in place for a week now and no problems. It's nice to be able to actually see into the reservoir, whereas the OEM style with the metal "shield" prevents that.

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I've been wondering about the usefulness of those sight windows. Yes, I can see the oil level in the crankcase, but for the life of me, I cannot see the brake or clutch fluid level. Maybe the stuff is just too clean? Should I let it sit in the bike for several years and then it will become visible? Seriously, does the level only become visible when the reservoir is low on fluid?

SMSW said:

I've been wondering about the usefulness of those sight windows. Yes, I can see the oil level in the crankcase, but for the life of me, I cannot see the brake or clutch fluid level. Maybe the stuff is just too clean? Should I let it sit in the bike for several years and then it will become visible? Seriously, does the level only become visible when the reservoir is low on fluid?

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Since I cannot see what you're seeing, I'd say you should open the master cylinder up and inspect your fluid level. Both my windows turned yellow and cracked and I couldn't see a thing through them. Also DOT4 fluid is hygroscopic and absorbs moisture out of the air - can cause corrosion issues in the caliper over time. You should flush your fluids every 2 years IMHO.

+1 on the overfill suspicion...
Even with slightly yellowed glasses one could normally spot the air-bubble behind.
Hint: only fill to MAX line when new brake pads are installed; by this you'll have actual wear indication via the fluid level.

dkruitz said:

Since I cannot see what you're seeing, I'd say you should open the master cylinder up and inspect your fluid level. Both my windows turned yellow and cracked and I couldn't see a thing through them. Also DOT4 fluid is hygroscopic and absorbs moisture out of the air - can cause corrosion issues in the caliper over time. You should flush your fluids every 2 years IMHO.

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All fluids on my bike have been flushed at least every two years - and i think last time the brakes were done again about a year after the previous flush. So, yes, at least this is not a problem.