Master Cylinder replacement

I have been looking into replacing my front master cylinder for my 1981 KZ650 H1 CSR. I am wondering if anyone has tried this type that is shown in the attached picture? They list as 14mm bolt. How does that match up to the 650's 1/2 inch? My calculator tells me that is 12.7mm

Just wondering what you guys think of this..

cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll...I%26otn%3D3%26ps%3D5

or do I go back to looking for an original Kaw piece?

Thanks,
Dave.

If existing m/c is 1/2" with single front disc, the 14mm should be okay (but wouldn't use it with dual front discs, regardless of what the seller is saying).

KZ's with dual front discs use the larger 5/8" m/c.

The listed m/c is a handsome piece, but I have no personal experience with it or it's build quality or longevity. And parts might be unavailable.

The $50 price appears higher than cost of rebuilding existing oem m/c, if rebuilding is a feasible option, and assuming availability of rebuild kit for oem m/c.

If the new unit is fitted, let us know your opinion about it.

Good Luck!

Edit -- Might consider this m/c rebuild kit from Z1E.
master cylinder rebuild kit $32.24

I used same/similar rebuild kit on the single disc m/c on my Kz900. Only problem I had was I needed the motion pro circlip pliers to remove the circlip that holds the piston in the m/c. This almost doubles the price of the rebuild kit if you don't have these.

www.z1enterprises.com/detail.aspx?ID=2868

He may be getting a different master cylinder for a number of reasons - the stock unit is a leaker & has an angled mount which would be no good for flatter handlebars.

One or two KZR guys have installed those w no problems.
Looking to the future in the event I ever get one of those, I contacted the seller about rebuild kits for the new units, and he said they were available. I didn't ask a follow-up question about where to get 'em, though.

I actually just bought one of these off eBay over the holiday weekend here . I have a single disc setup on my 78 kz650. I will let you know how it is once I install it. I should be getting it by Friday. I'm still going to rebuild the original one but it needs to be cleaned and painted. I needed a quick fix so I could ride!! I have the time now since hours have been reduced at work.

I received my master cylinder today I bought off of Ebay. I have to admit that for $50 plus shipping its a great deal. It looks great and works perfectly fine so far. I didnt have to modify anything. Pretty much a perfect fit. The only thing is that there is a space between the master cylinder and the switches. I think if I move over the switches it will look fine. I plan on putting new bars anyway. The reservoir does hold a bit more fluid than the stock. Not sure if that will make a difference for anything. Maybe it could actually handle a dual disc setup.

leorider wrote:

I received my master cylinder today I bought off of Ebay. I have to admit that for $50 plus shipping its a great deal. It looks great and works perfectly fine so far. I didnt have to modify anything. Pretty much a perfect fit. The only thing is that there is a space between the master cylinder and the switches. I think if I move over the switches it will look fine. I plan on putting new bars anyway. The reservoir does hold a bit more fluid than the stock. Not sure if that will make a difference for anything. Maybe it could actually handle a dual disc setup.

Thanks for the report.

For fitment purposes on shorter handlebars, would be nice to know how the length when fitted compares to length of the oem master cylinder between switch and end of banjo bolt. The oem measures approximately 5 1/4 inches (see green line on pic below).

[Click on image to enhance view]



This would show whether or not the new master cylinder affords additional space for fitting everything closer in on shorter handlebars without hitting the tach.

A pic of the fitted new master cylinder would also be helpful.

The additional reservoir capacity does not make a difference in brake line pressure exerted by the master cylinder.

The smaller 14mm (or 1/2" bore master cylinder) is oem on KZ's with single front disc brake. With introduction of dual front discs, Kawasaki changed to the larger 5/8" bore master cylinder.

It is reported by owners using the smaller bore master cylinder with dual discs, that line pressure is excessive, and readily causes front wheel lock up in an emergency stop, with loss of control and resultant bike tip-over. In other words, the smaller bore master cylinder is too sensitive for dual front discs.

While it might be erroneously assumed that lesser squeeze needed on the brake lever would be more desireable, it's important to remember that a harder squeeze should not tend to prematurely lock the front wheel.

For the same reasons, using the larger bore master cylinder with a single front disc would require a harder squeeze to produce equivalent braking.

So please be mindful of the above considerations, and carefully test the operational effect of any front brake system change before the next emergengy stop situation arises.

Good Luck!

OK I will post the pic of it. I will do it ASAP. Probably by tomorrow.

Here are some pics of the ebay master cylinder I bought from USA motorcycles. Works great but there is a space you will notice from the M/C to the switches. Im not worried about it right now as I plan on changing the bars. I will worry about it when I change the bars and see how everything fits.

Apparently I dont know how to attach pics. Im trying to attach but it wont accept them. I took the pics with my Iphone.