Speaking of Master Cylinders...

[Justin B.]

NEVER give your bike a vacation/time off for good behavior.  I gave the Dawg what I felt was a well deserved rest after flogging it unmercifully for several months after the rebuild.  Today I decided to wake it up, adjust valves, change oil, etc., and discovered I had no brakes - zilch!  No problem, I thought, just must have gotten some air in 'em. yeah, right...

I pulled the bike around to the front of the house and started working on it when it was about 100 degrees.  Re-torqued the heads, got rid of the rocker shaft end-play, adjusted valves, and changed the oil.  First glitch was discovering that the big box of filters I had contained only filters for a bike with oil cooler so I ordered some WIX filter kits from Rock Auto for $7 and change each.

SHAMELESS COMMERCIAL - Since I no longer have my RT PM me if you need a filter...

I hooked up the Mity-Vac and pumped and pumped and nada - the freakin MC is plugged.  I had originally used a 12mm MC when I rebuilt this POS but later scored a 14mm for a very good price but never swapped since I had gotten used to the extremely progressive feel of the 12.  

I had no desire to overhaul the 12mm cylinder so I stuck the 14 on, hooked up the Mity-Vac and pumped it down, and it feels great!  The feel is between the 12 and 16 (duh...) and still feels somewhat progressive but you don't have to mash the lever all the way to the bar for max braking.  So I pulled it out of the garage to hose off all the brake fluid (it was then 106 degrees) and we'll see how it does on the morning commute...

[Rob Valdez 79 R65]

I pulled the bike around to the front of the house and started working on it when it was about 10 degrees.  

Wow!  10 degrees to 106!  What a wild fluctuation!  

[Justin B.]

Oops, lemme fix that...

[Milo_357]

I need to "score" a 15 for my change from single to dual fronts...  Then again, pigs may fly and the one I have will work perfectly....  

CAN you take those things apart?  It's got the ring clamps or whatever you call them in it, right???

ugh... I am getting tired of this...

[Bob_Roller]

You need a pair of snap ring pliers to get the snap ring out .

Then you just pull the piston assembly out .

106 F, you havin' a 'cold spell' there in northeast Texas !!!!!!

[Semper Gumby]

Does a 15mm or 14mm round reservoir master cylinder exist anywhere on the Round reservoir bikes?

[Milo_357]

Does a 15mm or 14mm round reservoir master cylinder exist anywhere on the Round reservoir bikes?

Gumby, there was a round reservoir on my parts bike and it's a 15mm that went to a dual front brake.

[Justin B.]

After a commute with the 14mm cylinder I have to say that I really like it!

[Semper Gumby]

Does a 15mm or 14mm round reservoir master cylinder exist anywhere on the Round reservoir bikes?

Gumby, there was a round reservoir on my parts bike and it's a 15mm that went to a dual front brake.

Ooogh  Does it work?

[Barry]

Does a 15mm or 14mm round reservoir master cylinder exist anywhere on the Round reservoir bikes?
 

If you want to go a bit smaller the 79's single disc bikes had a 13mm on a round reservoir.

[oz_johnno]

I need to do something with my fjront brake master cylinder for a road worthy.

It leaks.

Whats the best way to jfix it, just replace anything that is worn, or go through the whole thing with an overhaul kit?

How do you tell what size cylinder you have, do you need to hone it?

Thanks in advance

OZ

[tvrla]

OZ - if it's leaking, it will need, at a minimum, a rebuild kit.

But ---- there is a very very slight possibility, a clean up could fix that.

Pull it apart, inspect the bore very carefully. You're looking for pits where moisture collected - usually mid bore on the bottom side. Leaking is caused by corrosion towards the 'at-rest' area of the bore near the retaining clip. Leaks are also caused by a worn seal on the piston. Seals don't rip normally, just lose their sharp edge, so if you're looking for a non-symetrical characteristic, nothing will leap out at you.

If the bore isn't pitted, then it won't be a waste of money to rebuild it.

[oz_johnno]

thanks spokes, shoved a kit through it, no probs, all good