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Master cylinder sight window replacement

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Who has replaced their crapped out plastic window with a glass one? Do I toss the o-ring and epoxy the new glass one directly to the casing? Do I need the little metal disk in there?

Thanks!

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Assuming you only need a 18mm one.....

The sight glass is not a normal replacement part, not available from an OEM supplier.

There are many non-OEM parts out there that may or may not work.

 

Frankly, I am surprised the guy has them. I cannot imagine he'd of had a batch made up and hoped to sell enough to cover costs. I'd think he'd of had to get 1,000 made up and paid for. When I've had custom grinds of pistons, IIRC, I had to order a minimum of ten at a time. Last time was in the late 1970's and they were $75 each. I still have one, I cut it up and turned it into an ashtray.

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I may even give up the quick checkability of the window and glue a dime in there. It'll never leak anyhow right.

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I may even give up the quick checkability of the window and glue a dime in there. It'll never leak anyhow right.

There is next to no pressure. So if your current one leaks, a brake fluid resistant epoxy covering it is all you need. But realize ever non-oem repair detracts from the value of the bike.

 

I've never had any use for the window myself. I change the fluid every year or if the bike becomes submerged. I always look for signs of leaks

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I'm talking about a 32 year old forest rat bike. I'm more concerned with function than resale. I think it's value has bottomed out.

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I'm talking about a 32 year old forest rat bike. I'm more concerned with function than resale. I think it's value has bottomed out.

Gotchya. Now I understand why the desire to buy a new master is not high on the list.

 

Assuming the old sight glass is still there but leaking, I'd clean it 101% clean with brake parts cleaner and use an epoxy that is brake fluid safe. You can alsways take a plastic cup, punch a hole, epoxy it, put some brake fluid in for a few days and see it leaks/softens. Keep us abreast of your luck.

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I may even give up the quick checkability of the window and glue a dime in there. It'll never leak anyhow right.

 

I did just that on my 1989 DT200 yamaha , 2 years on and  still holding fluid . It was impossible to see fluid level anyway !

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