Posted 2/8/2016 3:32 AM (#87825) Subject: Advantage of one master cylinder over another
Location: Eastern WA
91 wing and champion daytona 2+2 sidecar.
Our wing and sidecar have sort of crappy brakes. The sidecar/motorcycle stops straight enough. The car doesn't try to come around at all. Iit's just that it takes a while to stop.
I doubt you could really lock up anything in an emergency. Maybe the front wheel if you really tried but I'm not really sure you could actually get it to slide over about 45 mph.
The rig feels under braked to me.
Everything is in good working order. Good or new disks, OEM brake pads, new fluid. No sponginess, everything seems to be firm and well bled.
The sidecar brake is presently hooked into the rear master cylinder which provides pressure to the front left disk, the rear disk and now the sidecar wheel. (linked system)
The front master cylinder supplies the right front disk only.
In the instructions that came with out Champion car it says that they highly recommend the purchase of a new Champion mastercylinder for the handlebar and to combine the front non linked motorcycle brake (right caliper) in the circuit with the sidecar brake from that master cylinder.
My question is if I changed to the champion master cylinder would it give me better brakes? Since the car and bike stop straight now without the car trying to pass the bike would I really gain anything by changing to Champions master cylinder?
Anyone ever run one of these double cars with the recommended master cylinder on the front handlebar after running with the car brakes plumbed to the back first? Were the brake noticeably improved with the Champion master cylinder?
Anyone find a way to beef up the brakes on the gl1500?
Posted 2/8/2016 9:14 PM (#87833 - in reply to #87825) Subject: Re: Advantage of one master cylinder over another
Location: Wayne, NJ
A brake system basically tranfers pressure, not volume although disc brakes move a little more fluid than drum brakes do. (At least on automobiles). When you added the sidecar to the rear master cylinder you basically took away 1/3 of the pressure to 1/2 of your brakes. That's probably why Champion recommends connecting the sidecar to the larger master cylinder to the front brake. You could try what VLAD suggests but still connect the sidecar to the front master cylinder.
Posted 2/9/2016 1:33 PM (#87838 - in reply to #87833) Subject: Re: Advantage of one master cylinder over another
Location: Minneapolis, Minnesota
Transfer of pressure is certainly what actually stops the vehicle but there has to be enough fluid in the system to feed the wheel cylinders. Here we are talking about the available fluid from the master, that is the difference between the amount of fluid in the master at rest and the fluid remaining when the master is fully compressed. That delta has to be large enough to fully actuate all the wheel cylinders on that circuit. If you add a wheel cylinder and your master has adequate excess capacity to service it you are fine but if not you will never achieve the maximum braking that the cylinder might provide AND you will dilute the performance of the original brakes on that circuit. The net is, it's time to do a little math to see if your master displaces enough brake fluid to fully provide for the original brake cylinder[s] AND the added sidecar cylinder.
Delta from the master must equal or exceed the combined delta of all the other cylinders on the circuit. This link will figure the volumes of your cylinders. Use the piston throw for the length number.