1980 Kz750E Front Master Cylinder

Working to resurrect and make mechanically sound the 750, I need some advise on cleaning the front M/C. I soaked it in berrymens for a little more than 24 hours, came out better but still lots of corrosion in the reservoir. I’m concerned about the sight glass. It’s the first M/C I’ve done with one. How can I successfully clean it and remove the paint without damaging the sight glass. In the past to remove corrosion I’ve given parts a soak in CLR.  The bore is nice the piston came out easily. I have yet to ride the bike but just pushing it around the garage the front brakes worked. I do plan to put new seals and dust boots into the calipers next. Right now I want to finish up the M\C first.

 

 

 

 

I have to thank Nessism for the recommendation on LH drill bits from HF. One of the reservoir cover screws was stripped. I started with a small bit to try and get some heat into the screw. Followed by a larger one that I thought might grab the screw, if nothing else just take the head off. It grabbed and the screw backed out really easy. 

Thank You.

 

You could pry out the sight glass. saturate it with silicone spray beforehand to help lubricate the seal.  I suppose there's the chance that the seal could tear. I've only removed the sight glass on a junk 750H Ltd master cylinder & it came out fine (virtually the same m/c as the 750E).  If need be, the seal could be reinstalled w a gasket sealant suitable for brake fluid. The sight glass isn't under pressure, so I wouldn't think using a sealant would be a problem. 

Alternatively for possible fitment, the sight glass is probably 25mm, so you might be able to use the seal from an oil level sight glass, but I haven't tried it.  Suzuki 25mm >> www.z1enterprises.com/oil-level-lens-suzuki.html ... you'd be delving into unknown territory. hee. 
Z1Enterprises doesn't list the size of the various Kawasaki sight glasses.  www.z1enterprises.com/oil-level-window-k...00-kz1000-kz400.html or   www.z1enterprises.com/oil-level-gauge-kawasaki-2.html   or   www.z1enterprises.com/oil-level-gauge-kawasaki.html (see edit)

Edit:  the last one appears to be the best match. no measurements.  It should be about 25mm.
Partzilla pic w ruler >> www.partzilla.com/product/kawasaki/52005...efb1a49d6a349fd9db4b
I'm assuming the 750E m/c sight glass is 25mm OD.  KZ650H/750H m/c orifice ~25mm I.D. x ~6mm deep

Thanks Martin. The M/C seems a little scarce. I have been looking for one. All I find is the “H” and they differ in the mounting. The “H” has the handle bar clamp and lever skewed so the reservoir sits semi flat on the buck horn style bars. That said I’d hate to reduce an albeit ugly yet working item to a paperweight. 

You could go with a more modern master cylinder, unless you want to keep it stock.
I installed one from a 2014 Honda CBR500 onto my 81 KZ650-CSR. it's single disk.  A dual disk should be easier to find.

 

Still looking for advice 

Did you try to make a cleaning tool?  Some sort of L shaped tool that can fit into the slot ?

If you decide to go for broke this method will work.  I've got some MIL-SPC grade RTV sealant I'll donate to the project if you decide to go that way.

I’m sure I can clean behind the sight class. My question is what chemicals can be used to strip the finish and also to remove the corrosion without damage to the sight glass?

Paint stripper?  Mask off the area around the sight glass.  I'd media blast it, after masking, using soda.  If you don't have a compressor that's not an option though I suppose.

I might suggest brake fluid to remove the paint as that is what has removed the paint that is gone and it should not have much if any effect on the glass. It will not do much about the corrosion but brake clean and a brush might. 

Well I went for it. I figured I’d either have all winter to find a replacement, buy something recommended by Martin, or I’d have success. The latter is it. After 2 one hour soaks in CLR, some scrubbing with a stainless steel brush, and getting into all the little nooks with the dremel it’s almost ready for paint. Tomorrow I’ll scotch bright it up and get a few coats of VHT caliper paint on it.

Almost ready to reassemble. I forgot about the top and the bar clamp. They are painted but waiting to cure. Could have done better but it’s 95% better then it was. Kind of a dry spot on the back. A little heavy near the level lettering. It will work!