Twinpot Brake upgrade on 78 Skunk

[Assaf]

Great. Thanks for your answers folks.
I guess the remaining question is just, what's the process?
As Greg asks, have you got that documented anywhere online?
Or if it's within this thread, can you point us to the right page?
Thanks

[Hovmod]

Oh, I am SO doing this.
Reading up on the thread now.

[salty_monk]

Procedure:

1. use 2 x 6mm or 1/4" bolts to bolt spacer to back of CBR Rotor
2. Drill Holes through spider on Suzuki pattern at 8mm (straight through, no pilot. On a pillar drill, press is best as they need to be straight). Remove 6mm bolts.
3. Cut 5mm from Speedo Drive dust cover (if necessary). This leaves about 5mm of dust cover remaining (not necessary on about 20% of the ones out there. It will JAM THE WHEEL if you do not do this cut on one that needs it). I do this with a hacksaw with dust cover clamped in a vice by it's lip.





4. Fit rotors & dust cover using stock bolts & tabs with spacer behind them.
5. Fit caliper to fork using stock bolts (no washers) with blue loctite. Use a further 40-45mm 8mm bolt with nut on the lower fork bolt location (user supplied, get at least an 8.8 bolt, fine thread is better if you can get it, use loctite). Round spacer goes between bracket & caliper. Bracket goes on the OUTSIDE of fork leg.



6. Fit wheel as normal.
7. CHECK CLEARANCES BEFORE RIDING.

obviously you'll need to fit lines, bleed brakes & do all the normal checks etc.

[MadCapsule]

Do the rotor spacers need to be installed when using stock GS rotors instead of CBR rotors?

[salty_monk]

If you use a GS550 Rotor on each side then no, you don't need the spacer.

Some caveats:

The GS550 rotors don't give exactly the right offset but they work fine.
The GS550 rotors are very heavy (added unsprung weight, not good for handling).
The GS550 rotor material does not really suit the stock Tokico pad material, it tears them up pretty quick.

With that said, although they are getting rarer the GS550 rotors are still the cheapest route to doing this upgrade as the rotors are usually so cheap.
It has been known for people to score CBR rotors for $50 though (scored a set myself a few weeks ago for that price) which makes them similar to the $40+ you'll spend on GS550 rotors. Just got to search & be patient.

I have not had much chance to try it (always sunny here) but I'm sure the CBR rotors would give a noticeable improvement in the wet.

[gearheadE30]

It has been known for people to score CBR rotors for $50 though (scored a set myself a few weeks ago for that price) which makes them similar to the $40+ you'll spend on GS550 rotors. Just got to search & be patient.

I have not had much chance to try it (always sunny here) but I'm sure the CBR rotors would give a noticeable improvement in the wet.

I got a pair of rotors for $50 on Ebay, shipped. You just have to be a little creative and very thorough in checking the rotor interchangeability. A lot of hondas used those rotors, and a lot of Kawis used the calipers.

Yes, the brakes are a massive improvement in the wet.


On a side note, when I got my rotors, I thought that one of them was warped. Turns out that these semifloating rotors can get knocked out of alignment, and the fix is to make sure all of the rivets are free and can spin (use WD40 to free them and lube them and then make sure you get it all out with brake cleaner. Be very methodical about this. You don't want WD40 in your brakes). Then you take a block of wood and a mallet and whack the crap out of the rotors, and they self-align. I went from almost 1/8" of runout to a perfectly straight rotor with this.

[greg78gs750]

thanks for that tip! when i put stuff on it is always spotless, but good to know what to look for! not sure i can wait till winter to do this mod.

I got a pair of rotors for $50 on Ebay, shipped. You just have to be a little creative and very thorough in checking the rotor interchangeability. A lot of hondas used those rotors, and a lot of Kawis used the calipers.

Yes, the brakes are a massive improvement in the wet.


On a side note, when I got my rotors, I thought that one of them was warped. Turns out that these semifloating rotors can get knocked out of alignment, and the fix is to make sure all of the rivets are free and can spin (use WD40 to free them and lube them and then make sure you get it all out with brake cleaner. Be very methodical about this. You don't want WD40 in your brakes). Then you take a block of wood and a mallet and whack the crap out of the rotors, and they self-align. I went from almost 1/8" of runout to a perfectly straight rotor with this.

[Assaf]

Great.
Thanks for all the posts

[salty_monk]

I got a pair of rotors for $50 on Ebay, shipped. You just have to be a little creative and very thorough in checking the rotor interchangeability. A lot of hondas used those rotors, and a lot of Kawis used the calipers.

Yes, the brakes are a massive improvement in the wet.


On a side note, when I got my rotors, I thought that one of them was warped. Turns out that these semifloating rotors can get knocked out of alignment, and the fix is to make sure all of the rivets are free and can spin (use WD40 to free them and lube them and then make sure you get it all out with brake cleaner. Be very methodical about this. You don't want WD40 in your brakes). Then you take a block of wood and a mallet and whack the crap out of the rotors, and they self-align. I went from almost 1/8" of runout to a perfectly straight rotor with this.

Good tip on the rotors - thanks for posting that.

Sorry that you get wet

[salty_monk]

Just bouncing this back to the top... It's about Wrenching season for a big chunk of the US again

[salty_monk]

Set of calipers here for $29 shipped (not mine)...

http://www.ebay.com/itm/89-KAWASAKI-ZX600-NINJA-ZX7-ZX-600-FRONT-BRAKE-CALIPERS-SET-pad-lot-OEM-factory-/290763567198?pt=Motorcycles_Parts_Accessories&hash=item43b2dbf05e&vxp=mtr

[VTRauder]

This is an amazing thread, just what I was looking for. Thought about doing a front end swap, but I feel like this is the more elegant solution(not to mention cheaper)


Salty Monk, do you happen to have any more kits? or alternatively will you be making any more in the future? This is at the top of my list of mods I need to do

[salty_monk]

Yes, got some sets here

There are plenty of calipers on Ebay & some rotors (for around $100). I can likely make you up a full set for $250-$275 plus shipping if necessary (I'll drill the rotors & povide the 3rd bolts but you still need to paint plus do any caliper reconditioning (usually limited to cleaning & perhaps new seals & pads).

[Chuck78]

Are the bores of the single and dual master cylinders the same on our bikes? I have a single disc 77 GS750, and not sure if I need to upgrade to a dual MC off of our bikes (I will be stripping some parts off of a GS650G tomorrow to get the dual disc fork legs and engine parts), or if the original single caliper MC is fine.

I certainly like the looks of the slightly newer MC's with the aluminum box reservoir and sight glass versus the older style like mine with the screw-on plastic reservoir.

As I understand, all of the lever/MC's that were an OEM match to the Ninja calipers DO NOT have the threaded mount for the mirror? I remember mention of someone saying they used an old clamp half that has the threaded hole for the mirror, and attached it to the newer lever/MC that otherwise did not have a mirror provision. Any ideas? I'm fine with a slightly newer style GS master like I described, but just curious

[salty_monk]

Single = 14mm

Dual = 5/8" (16mm)

14mm will give more lever travel (might feel spongey).

This is the one that I use. They are new, work great, right bore. Work with stock mirrors & importantly they are cheap!

Good replacement for anyone using stock brakes too.

http://www.ebay.com/itm/FRONT-BRAKE-MASTER-CYLINDER-WITH-LEVER-GOOD-CONDITION-EX650-EX-650-NINJA-650-R-X-/330815705286?pt=Motorcycles_Parts_Accessories&hash=item4d062710c6&vxp=mtr