Need front m/c

[mack]

Need new master cylinder. My reservoir is leaking at the join between plastic and metal base. Help!!!

[Ivan]

Does the MC have screws in the bottom of it? IIRC the older reservoirs were held in place by a couple screws. You could just pop the reservoir off and replace the oring. The newer style is a snap in fit, and with the age of the plastic, I don't think it would stand up to prying it off for a fix. That being said, if you end up needing a different one, member Andreasweiss usually has some pretty good deals. Also, an aftermarket Nissin with a separate reservoir can be fitted, looks trick, but is pricey.

[Crazcnuk]

Some were held on by the 4 screws up top (if they are long) and the reservoir was only held in the base by an o-ring.

You just tilt it over and pull it out.

I don't think any of the Yamaha stock ones were that way, but Honda and lots of replacement ones were.

[DGXSER]

I have primarily worked on the 81 model Specials. All that I have worked on have had four screws that go through the cover, through the reservior and into the MC body. Using two smaller screw drivers, I have pried the reservior out little by little from one side to the other.

[mack]

Mc

Mine is pressed in place and I don't think it has a gasket at the bottom. Four long screws go through the top and down through the plastic or nylon what ever this is. I've cranked on the screws hoping to pull it down tighter but all that did was mess up the lid gasket. Looked at the aftermarket ones, and they suck. Not familiar with the one you mentioned. Got a site?

[Crazcnuk]

Yes, they are pressed together, the bottom of the bowl has an o-ring around the outside of it. You should be able to pry it apart.

With the age, though, the reservoir is probably brittle. Youhave to pry it up a little, so that you can rotate the reservoir and gently pull up on it while turning.

[crazy steve]

Mack, these are sealed with a o-ring where it goes into the master cylinder body. Take off the cover, etc, then twist while pulling up to get the plastic reservoir off. If it's corroded (and if it's leaking, it is) you'll have to work at this; take your time so you don't damage anything. Remove the o-ring, clean it and it's groove out, and it wouldn't hurt to put some silicon sealer on the reservoir base before reinstalling it. As long as the plastic isn't cracked clean through, that should do it.

While Yamaha is very unhelpful about replacing the reservoir (not showing this as a replaceable part), I believe the G and H standard is the same, as well as the XS750/850 specials. There may be others that will fit; I know the E and F standards are different and won't work on a special. If yours is cracked to the point it's leaking, let me know; I have a left-over special reservoir you can have for postage. It's pretty badly sun-dried, but didn't leak.

'78E original owner

[Bullet]

I bought a new one from Mikexs Canada .. my original OEM was iffy, so rather than risk it, just went the new aftermarket route ..

If you want to stay with original, you can get the OEM res cap and a rebuilt kit only, the o-ring between the plastic res and the housing was never available as a seperate item anyway.



http://www.xs650direct.com/products-71.html

part # 08-0265

works fine .. lots of pressure, using SS lines and DOT 5 fluid in mine ..

They ship same day from Ontario using Fedex and it's cheap and fast ..

[CatatonicBug]

I bought a new one from Mikexs Canada .. my original OEM was iffy, so rather than risk it, just went the new aftermarket route ..

If you want to stay with original, you can get the OEM res cap and a rebuilt kit only, the o-ring between the plastic res and the housing was never available as a seperate item anyway.



http://www.xs650direct.com/products-71.html

part # 08-0265

works fine .. lots of pressure, using SS lines and DOT 5 fluid in mine ..

They ship same day from Ontario using Fedex and it's cheap and fast ..

I would strongly recommend that one! It's the same design as the LH used (Part #08-255), with a full-metal housing. The reservoir is cast as part of the one-piece MC. No plastic to decay in sunlight.

[Bullet]

The reservoir is cast as part of the one-piece MC. No plastic to decay in sunlight.

Exactly !!

It is very similar to the one on my 2007 OEM Honda Sabre.

[mack]

Rubber boot

Does the yamaha rubber boot fit over the lever, plunger mechanism and switch?

[Crazcnuk]

"using SS lines and DOT 5 fluid in mine "

How long have you been using DOT 5?

The seals in our bikes are not made for silicon based fluids and may fail?