Front Master Cylinder Advice

[rputney01]

I bought a rebuild kit for the front master. Once I wrestled the snap-ring out and cleaned the bore, it became clear to me that my master had a smaller bore than the kit. I went back to the fiche and determined that I had the right kit. So, it would seem that I don't have the stock master cylinder. Although the fiche indicates a round reservoir, the manual indicates a rectangular reservoir for the "S" and "E" models in 1979. Mine is round. There is a lot of travel in the lever before the brakes engage. I'd prefer a little tighter feel.

Previous threads suggest that I should have a 5/8 bore. Mine is 14mm. Used parts on E-bay run about $80 to $100 and I'm guessing I'd need to rebuild a used one anyway. Does it make sense to just order a new OEM part for a newer bike with dual front disks? If so, any recommendations as to what would work well for my bike?

Thanks.

[Nessism]

You have the wrong master for your bike. 14mm masters go on bikes with a single disc up front.

Any 5/8" master will work although many modern ones don't have provision for a mirror.

[rputney01]

Thanks. I've started looking for a replacement.

[Rover]

Hi rputney01

I have one available.Would you be interested in trading it for an air cleaner box? As I see you have a 4/1 exhaust and may be running pods.
PM me if you are interested.

[Suzuki_Don]

You have the wrong master for your bike. 14mm masters go on bikes with a single disc up front.

Any 5/8" master will work although many modern ones don't have provision for a mirror.

Also a lot of modern bikes have fairings which usually means that they also have a separate reservoir for the master cylinder. The reservoir is connected to the master cylinder by a small rubber pipe and this is all hidden under the fairing. It would look unsightly on an unfaired bike. And as Ed says there also is no mirror mounting point as this is on the fairing of modern bikes as well. So unless it is a master off a modern retro, or unfaired bike it would not be the best option.

[rputney01]

Hi rputney01

I have one available.Would you be interested in trading it for an air cleaner box? As I see you have a 4/1 exhaust and may be running pods.
PM me if you are interested.

PM sent. The bike had pods when I got it. I don't have the air filter box.

Thanks though.

[rputney01]

Also a lot of modern bikes have fairings which usually means that they also have a separate reservoir for the master cylinder. The reservoir is connected to the master cylinder by a small rubber pipe and this is all hidden under the fairing. It would look unsightly on an unfaired bike. And as Ed says there also is no mirror mounting point as this is on the fairing of modern bikes as well. So unless it is a master off a modern retro, or unfaired bike it would not be the best option.

I have a '79 GS1000S, so it has a cowling with the mirrors attached. I can only see my elbows, but I'm having some extensions fabricated to move the mirrors out about an inch and a quarter to see if that helps. In any case, it makes the need for a mirror mount less important.

I've looked at some of the newer masters with a separate reservoir. A couple of after-market companies make a billet mount for the handlebars to attach the reservoir. I've seen some used Brembo radial units mounted that way. One of them had a billet reservoir cap that matched the mounting bracket. They are expensive, but to your point, I'm more concerned about how it would look. It would fit behind the cowling and sits up about 5 inches above the handlebar. It wouldn't effect my view of the gauges, and the performance is supposed to be very good.

Another alternative in a newer model with an attached reservoir from a cruiser type bike. I appreciate the advice, thanks.