brake mods

xsleo · Posted: April 12, 2009, 3:01 pm Post subject: brake mods

I just got the bike together.
I thought I'd post a pic to show the brake mods.
The bike is a 75. I put a 79 front fork on, so I could use the later type dual disc brake. I have the slotted rotors from an xs1100 on there.
On the rear I put the disc brake on. Slotted disc here too. Mounting the master cylinder in the right place was the trickest part. I swapped the swing arm for a 79 disc brake swing arm, it seemed easier then locating and mounting a place for the brake strut to hook to.

Retiredgentleman · Posted: April 12, 2009, 3:56 pm Post subject: Re: brake mods

You've got real good brakes there leo. I get by with just single disks front and rear, but I did drill them out. I don't like the glaze that builds on the disk, so just recently used 80 grit sanpaper to sand the glaze off and roughen the surface.

xsleo · Posted: April 12, 2009, 5:46 pm Post subject: Re: brake mods

Yes, they do work well. They surprize me everytime. I should be somewhat used to it, my Harley has the same setup.
I went with the slotted rotors because I think they look better. I didn't have to do all that drilling. The slotted rotors are 5mm thick not 7mm thick so they weigh less. I got them off ebay for like $34 plus shipping. just bolt right on. couldn't get much easier.

jetero41 · Full Member Joined: Mar 19, 2009 Posts: 17

'79 swing arm, huh? Are there no master cyl mounting points on an '83???
Am doing a disc converssion on my '83 and the location and actuation of the master remains my only concern.
Would appreciate any input.
Thanks

xsleo · Posted: April 15, 2009, 3:01 am Post subject: Re: brake mods

As I was doing the changeover I was looking on ebay and a 79 swing arm was in it's last half hour with no bids, I bid a few bucks and got it for the starting bid of 99 cents. The shipping was like $9.99. Couldn't beat that. Put in a new set of bushings, set to go.
To mount the m/c I got the brake pivot installed and held the m/c up by the frame above the foot peg mounts, moved it around till it looked right and the push rod from the brake pivot looked right. I don't have a welder , I have a small set of torches. I used these to braze a pair of readyrod/all thread connectors to the frame in the right place. If you can get a good look at an xs with a rear disc it will help you get an idea where it should mount. I looked at as many pics as I could before I did the mounts.
You will need the disc brake brake pivot shaft. I tried to mod a drum brake piviot shaft and it didn't work.
I am very pleased with the results.
Good luck on your swap.

jetero41 · Full Member Joined: Mar 19, 2009 Posts: 17

Thanks for the info.
Additional question:
Will the stock drum brake pedal work for travel and direction of actuation?
Again thanks.

xsleo · Posted: April 17, 2009, 2:38 am Post subject: Re: brake mods

The pedal is fine, the same pedal is used on both set ups. I have a few pics of what I did. I'll post them.
You will need to modify the pedal height adjuster. I removed the adjuster screw. Looked thru my scrap metal, found a small bent piece that would work. Bolted it on where the adjuster screw was. Used a nut on both sides of the plate to hold the adjuster screw in place and to adjust the pedal height. I don't think i have a pic of that.
A couple show the m/c mounts. One shows the mount on top of the swing arm for the brake strut.

HndaTch627 · Posted: May 14, 2009, 4:43 am Post subject: Re: brake mods

so what all is needed to do a dual disc setup up front? If i got the list correct

I'd need a l/s caliper off a 80 xs1100 as well as another rotor + hold down bolts.

What about brake lines/calipers? Is the dual banjo bolt how the front hoses are tied into each other? What about an upgraded master cylinder?

I'd really like to increase the stopping power of this bike.

xsleo · Posted: May 16, 2009, 10:45 pm Post subject: Re: brake mods

I used two xs1100 slotted rotors on the front.
Any bike with the same style calipers will work, any year xs 400, 500, 750, 850, 1100. The 750,850,1100 the standard versions are the same, the specials are different.
Their are other Yamaha's that have the right calipers. If shopping ebay ,look closely at the pics. If they look the same they should work.
On the mounting bracket there is an L or R the show which side they mount on.
Any lines that are the right length will be okay. Yes a double bango bolt is needed. The two lower lines bolt to the block on the lower tree with the double bango bolt.
I am using a m/c from an 82 Seca 650, any m/c with a 16 mm bore, or one marked 5/8 will work great. If it is a mm or two larger or smaller will be ok. A smaller bore will have a longer lever travel, but more power. The opposite for a larger bore. I wouldn't go more than a mm or two. To large and the brakes get wooden, hard to pull and not much feel. Too small and you will run out of room to pull the lever. You need to balance the m/c to the calipers. the calipers need the right amount of fluid to work and the m/c needs to push the right amount of fluid.

HndaTch627 · Posted: May 17, 2009, 12:10 am Post subject: Re: brake mods

awesome post, thanks

kingwj · Posted: May 17, 2009, 7:09 am Post subject: Re: brake mods

SR500 used a single left disc on the front. Make sure you are scavenging the standard model, the specials used different calipers.

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