rear master cylinder 79 special

[tony7914]

i have a question about the rear master cylinder on a 79 special i'm rebuilding. when i took it apart i didn't notice what order the ruber cups were in and i was wondering if someone could clear this up for me. the kit came with 2 cups, one is thicker than the other, which one goes on top of the plunger under the spring? any help would be great!!
thanks!!

[newmaac]

Tony, Go to bikebandit.com.
Follow the links to get your year/model. select rear master cly.
It will show you a schematic of the master cyl. You can blow it up to see the order.
For the future, for $10, you can buy an XS/XJ CD. It has the complete Clymers and Yamaha mauauls, as well as micro-fiche from all al the 1100 models., and a ton of tech tips.
I don't remember which of the members is selling them, but you can ask in another post.
Good luck

[ratbyk]

XS/XJ CD

To trace down the CD go to members at the top of this page. Find a member known as rockjok. Rob Mills in Montana. He is the source for this very informative CD.
E-mail him from the link provided from rockjok's members page. They cost $10.00 and are well worth it. In fact be a nice guy and send more!
The $10.00 covers Robs cost and any extra he donates to his local Humane Society.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"

[tony7914]

rear master cylinder

hey there!
i have the cd but it's hard to see even when you zoom it in allot, i was hoping someone out there might have rebuilt one recently and remembered if the thicker one went on the top or the bottom, i would hate to have the brakes fail because i got the cups in the wrong places.
any help would be great!! thanks!!

[randy]

There's a better view of the layout on Yamaha.com. You can even right click on the image, save it as 'something' and print it so you can bring it to the bench. If you have trouble, reply and I'll send you a printable file.

Have fun!

Randy.

[tony7914]

thanks randy!!
when i look at the picture on the yamaha site i can't tell which cup is which. they both look the same in the picture, but in the kit one is heavyer than the other. any help would be great!!
thanks again!!

[randy]

Sure. Here is the sequence:

Holding the rod straight up as shown in the fiche;

1. the thicker of the two cup goes on first. Make sure the 'lip' is facing up. It's final resting place is in the middle of the rod.

2. the thinner of the two cups goes on the tip. 'Lip' up.

3. Next the metal washer.

4. Then the metal ferrule.

5. last, the spring.

Lube the bore with Brake Fluid, then shove the whole works in, twisting a bit to get the cups in. Whilst holding it in against spring pressure, using your third hand, place the "U' shaped metal washer in the end, then the spring clip. You're done.

Hope this helps.

Randy