[WingMan71]

OK vintage bike enthusiasts, I have a parts mystery to solve.

This front brake master cylinder assembly was on the red 1983 GL650I Silver Wing I acquired some months back and am working on reconditioning. It is NOT the correct assembly for this bike, so I have sourced the correct assembly and replaced it.

That leaves me with this master cylinder assembly that I can't identify. I have been restoring vintage Japanese bikes for a few decades now, mostly Honda, but some Suzuki and Yamaha models mixed in as well.

The shape of the brake lever is particularly stumping me regarding which make/model of bike this MC belongs to.

Does anybody recognize this MC assembly and know what bike's it might be correct for?

 

[Randall-in-Mpls]

Isn't that the aftermarket MC commonly recommended on this forum?

 

[Cats]

Could be from a 1981 Yamaha XS1100 Midnight Special or 1982 Yamaha XJ1100 Maxim.

 

[WingMan71]

Could be from a 1981 Yamaha XS1100 Midnight Special or 1982 Yamaha XJ1100 Maxim.

The brake levers look right on those bikes, with the finger ridges. But, the master cylinder cups aren't rectangular, they're quadrilateral, in this case narrower on the forward edge.

Thanks for the ideas.

 

[WingMan71]

Isn't that the aftermarket MC commonly recommended on this forum?

Did a search for "aftermarket master cylinder" on this forum and found a number of threads.

Didn't find a picture of this particular master cylinder. I actually don't think this one is aftermarket. It has OEM look and quality to it, and I've seen plenty of OEM master cylinders.

I may post these pictures up on one of my Facebook vintage bike groups page and see if anyone recognizes it.

It would be nice to figure it out, since it fits and plumbs up right.

 

[CXPHREAK]

When I was building the thingy I hunted for an aftermarket master cylinder with a slanted reservoir.

Couldn't find one and went with a Nissin from Dime city.

I think that is a stock MC .... from something or other....

 

[bahn88]

It has a 5/8 marking...suggesting IF its Oem not of metric origin...

 

[Pim205GTI]

Looks to me like a Honda VF750 master brake cilinder

 

[WingMan71]

It has a 5/8 marking...suggesting IF its Oem not of metric origin...

That's what I thought at first.
But the OEM metric thread banjo bolt screws right in.

 

[ChopperCharles]

That's a Honda V45 or VF700C Magna master cylinder. 1982-1986. Only the Magna had those ridiculous buckhorn bars that required the crazy angle to keep the reservoir level. The V65 was spec'ed for DOT 4 brake fluid, and the smaller bikes specified DOT 3 on the lid. The bore is 5/8", which is suitable for two discs and two two-piston calipers. If you use this on a single-disc front end you will get a firmer lever with less travel, but also less feedback.

The lever itself is aftermarket JC-whitney most likely.

Charles.

 

[WingMan71]

That's a Honda V45 or VF700C Magna master cylinder. 1982-1986. Only the Magna had those ridiculous buckhorn bars that required the crazy angle to keep the reservoir level. The V65 was spec'ed for DOT 4 brake fluid, and the smaller bikes specified DOT 3 on the lid. The bore is 5/8", which is suitable for two discs and two two-piston calipers. If you use this on a single-disc front end you will get a firmer lever with less travel, but also less feedback.

The lever itself is aftermarket JC-whitney most likely.

Charles.

Thanks for that info Charles.

It certainly looks like the MCs shown on the Honda microfiche for those bikes. Particularly the inside of the bowl with the little metal flapper that keeps the thing from spitting in your face with the cap off.

The microfiche shows that these are not available new anymore which is no surprise.

What do you think would be a fair price for this to someone who needs one in working order like this one?

 

[ChopperCharles]

In working condition? $50 maybe. But yours has the dreaded sight glass deterioration. The plastic sight glass will eventually become soft and pliable and leak. There are some DIY repairs, but not worth it when an aftermarket master cylinder can be had for $25 or $30. Also yours has rash on it, which makes it even less desierable to collectors. And they made a MILLION Magnas, those parts are all over eBay.

Charles.

 

[WingMan71]

In working condition? $50 maybe. But yours has the dreaded sight glass deterioration. The plastic sight glass will eventually become soft and pliable and leak. There are some DIY repairs, but not worth it when an aftermarket master cylinder can be had for $25 or $30. Also yours has rash on it, which makes it even less desierable to collectors. And they made a MILLION Magnas, those parts are all over eBay.

Charles.

Hello again.

Well... it was working just fine when I removed it from the bike and it certainly looks good enough to be useable on a daily rider. Pretty clean on the inside too. Hate to see it go unused.

I guess the thing to do is offer it up to someone who needs it for free, just the cost of shipping.