Rear Disc Brake Set up

Geezer · Posted: October 5, 2006, 5:33 pm Post subject: Rear Disc Brake Set up

I am in the process of building a XS 650 Street Tracker. I have picked up an 18 rear wheel with the disc brake assembly and related componants from a 400. Does anyone have any advice on how the rear master cylinder should be mounted. Pics would be great. I have pretty much figured out how to modify the rear wheel so it will work but could use some advice also.

Guest · Posted: December 9, 2006, 6:41 pm Post subject: Re: Rear Disc Brake Set up

If you are using an RD400 wheel you will need to make up a 3/8" aluminum spacer for your sprocket. I suggest going with an RD 4 hole sprocket. The spacer then requires eight holes 12mm, four 12mm holes for mounting the spacer to the wheel and four recessed to mount the sprocket to the spacer. I mounted my brake disk directly to the wheel and made an offset torque arm to hold the caliper. Outer wheel spacers are easy to make from existing spacers. Your M/C should be mounted in the same location as newer XS's that had rear disk brakes. You will also have to fab a mount for the rear brake switch just to the right of the M/C. I'm sure members of this board can provide a close up photo of the MC location.

Barrett · Posted: January 26, 2007, 12:43 am Post subject: Re: Rear Disc Brake Set up

Spacers, well, my bike had disc rear. I did have to change the bearings in the wheel to fit the 650 axle, made the spacer tube that goes between the wheel bearings. Seems like my spacers came out okay. As for mounting the master cylinder, look at flat trackers or get brake stuff off of a Special. Flat track guys like the brake caliper down low with a brace coming up to the frame(has to do with load/unloading the suspension). My next street tracker/super motard is going to have forks, brakes, and maybe 17" wheels off of a crotch rocket(thanks ebay). The best part of street tracker stuff, no rules, run what you got or what you can get you hands on!
I just used the rear sprocket off of the XS 400(came with the wheel), a little different from an RD, but, close. It was larger, (lower final gear ratio 36 or 38 teeth) but, I got it as a short trip bike, not too many highway stints, it likes 101+ ocatane gas.

Guest · Posted: January 28, 2007, 8:28 pm Post subject: Re: Rear Disc Brake Set up

101 octane is just a myth...octane is percentage ratings
auto.howstuffworks.com...tion90.htm

tracker79 · Posted: January 29, 2007, 6:34 pm Post subject: Re: Rear Disc Brake Set up

There are several ways to produce an octane number, they all come pretty close to producing the same number. It`s a referance number, try running 87 octane gas in a 13.5 compression ratio engine and there will be no myth as to what will happen.

Barrett · Posted: January 31, 2007, 12:25 am Post subject: Re: Rear Disc Brake Set up

I guess you have never heard of CAM2 or C12 or C14 race fuel, Sunoco/DX, VP, Gulf/76 race fuels, etc... AvGas still comes in 100LL and 130LL. That sweet smell, yeah, that has to do with a more efficient burn process that involves those hydrocarbons from the link above, slow flame propagation and all. And, I am not talking about all those upper cylinder lubricants that the guys with big blowers use 10-71 and up....oh yeah, AvGas octane rating is at altitude for say a Cesna 150 in flight, it is around 97-98 octane at 670 ft above sea level (here in Tulsa, I did the math, allowing for atmospheric pressure at 78 degrees F).
Next you're gonna' tell me they made aluminum rods because they were lighter right? Tolulene, that is what was added to fuel in the old days to increase octane, not so much now, it causes liver cancer. Ever notice WD-40 smells different now?
So, go ahead, try a 12-1 or 13.5-1 motor with 87 octane gas, it will not fly, not even with Harley/aircraft style roller bearings. Catastrophic connecting rod and main bearing failure is an under statement.
So, fuel knock doesn't exist either? Guess I can do without a "knock sensor" right. Timing...ahh...I am over it....
Keep the shiny side up!
Brakes, yeah, brakes....use some off of a late model bike...

gentlemanjim · Posted: December 30, 2007, 3:13 am Post subject: Re: Rear Disc Brake Set up

Barrett wrote:

Spacers, well, my bike had disc rear. I did have to change the bearings in the wheel to fit the 650 axle, made the spacer tube that goes between the wheel bearings. Seems like my spacers came out okay. As for mounting the master cylinder, look at flat trackers or get brake stuff off of a Special. Flat track guys like the brake caliper down low with a brace coming up to the frame(has to do with load/unloading the suspension). My next street tracker/super motard is going to have forks, brakes, and maybe 17" wheels off of a crotch rocket(thanks ebay). The best part of street tracker stuff, no rules, run what you got or what you can get you hands on!
I just used the rear sprocket off of the XS 400(came with the wheel), a little different from an RD, but, close. It was larger, (lower final gear ratio 36 or 38 teeth) but, I got it as a short trip bike, not too many highway stints, it likes 101+ ocatane gas.

What 17" wheels work and what the size of the XS400 wheels?

amosey · Posted: August 15, 2008, 3:50 pm Post subject: Re: Rear Disc Brake Set up

Nice picture , I am working on building a bike and would like to incorporate some aspects of streettracker design into it. What did you use for your rear swingarm setup?
Aaron

sschering · Posted: August 15, 2008, 4:17 pm Post subject: Re: Rear Disc Brake Set up

I have a Rear Disk XS400 at home..
Would pics of the XS400 Rear MC mount help?

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