Twinpot Brake upgrade on 78 Skunk

[salty_monk]

I see EBC offers their pro-lite rotors for the CBR900RR. Do aftermarkets fit the GS wheels also?

They fit as much as the stock ones do... that's to say all of them need drilling / spacing correctly. I have fitted a few sets of EBC

[salty_monk]

Does this Vintage Brake chart still make sense? http://www.vintagebrake.com/mastercylinder.htm


What is the master cylinder ratio for the single disk + 14mm Ninja 250 MC?

Without doing a lot of measuring I can't say... but the stock is 5/8" and the stock Kawasaki is 5/8" and both feel ok. The Stock 250 is 14mm (as is the twin piston KLR) and the stock Suzuki single is also 14mm.

[The1970's]

I see EBC offers their pro-lite rotors for the CBR900RR. Do aftermarkets fit the GS wheels also?

[jabcb]

The Ninja MC is a 14mm (aka Ninja 250) if you use one or 5/8" (aka bigger ninja, concourse etc) if you use two...

Does this Vintage Brake chart still make sense? http://www.vintagebrake.com/mastercylinder.htm


What is the master cylinder ratio for the single disk + 14mm Ninja 250 MC?

[Chuck78]

I usually recommend using a ninja 250, GS500, or Bandit 400 master cylinder for the single disc setup, & I believe those are all 9/16"? It is basically the same as GS stock single and dual disc master cylinder bores. It was 5/8" for the dual. Funny thing is, despite being metric parts, the bore size i recall seeing cast into the parts in inch sizes on some of them! Sort of like inch sized tires worldwide, except for newer bicycles, & car/truck widths being in millimeters (but not rim diameters still, standard is in inches!)

[salty_monk]

The Ninja MC is a 14mm (aka Ninja 250) if you use one or 5/8" (aka bigger ninja, concourse etc) if you use two...

[The1970's]

Yes you will definitely benefit with just one side on a 750, as you will be getting twice the swept area and be going from 295 mm rotor up to 310mm. You need a 98 - 99 CBR900RR rotor to do this. And you just need the caliper bracket, you do not need the rotor spacer as that rotor already has 23 mm offset.

I would definitely recommend getting a good brand new set of pads and a stainless steel brake line if you are just going single-disc, you will want every bit of performance you can get. This setup is plenty adequate for a GS 550 which is about 50 pounds lighter than your 750.

Thanks for the info, I think I'm going to go for it and see what happens. I already have a cool set of (very expensive) blue anodized stainless lines. I'm not really looking for all out performance at the moment since my exhaust limits my ground clearance anyway. I just want a little better brakes for an extra margin of safety and for the occasional spirited riding I do. Also I'm in florida so all the roads are all straight
How about MC bore size? I've got a 14mm aftermarket MC for the stock system. What is the piston volume of the Ninja caliper?

[Chuck78]

Yes you will definitely benefit with just one side on a 750, as you will be getting twice the swept area and be going from 295 mm rotor up to 310mm. You need a 98 - 99 CBR900RR rotor to do this. And you just need the caliper bracket, you do not need the rotor spacer as that rotor already has 23 mm offset.

I would definitely recommend getting a good brand new set of pads and a stainless steel brake line if you are just going single-disc, you will want every bit of performance you can get. This setup is plenty adequate for a GS 550 which is about 50 pounds lighter than your 750. If you are riding a 750 really aggressively and on very twisty roads, or if you have a lot of big hills around, a dual disk would still be beneficial to keep them running cooler and not have to suffer from anywhere near the amount of brake fade when the rotor(s) get hot.
On a race bike, dual discs are also beneficial as then you have the fork twisting forces somewhat equalized since both fork legs are trying to twist under the braking force.

[johnod]

I'm sure there will be a benefit even with just the one caliper.

[The1970's]

I'm not sure if this has been discussed before in this thread but I have searched the best I can and can't find anything. Basically what I want to know is if there is any benefit to the twin-pot caliper on only one side? I'd kinda like to keep the look of the single rotor with spokes on the 78 Gs750 but would also like better braking performance. Common sense tells me that there should be some improvement with a larger swept area but is it worth it? If so how about MC size for a single caliper? Stock rotor or aftermarket?

[johnod]

I see, did not know that, good to know. Thanks.

[hannibal]

Thanks Chuck. Just wanted a sanity check.

Why should they be identical?

Tokico makes the calipers and Kawasaki and Suzuki both use them. The parts diagrams are identical. I assume the caliper components are made by Tokico (or likely a Tokico supplier) but Kawa and Suzuki package and price them differently.

[johnod]

Why should they be identical?

[Chuck78]

Should be identical parts...
Good to know the Kaw stuff is for rich people & Mr Suzuki prices parts for the common people, THANKS!

[hannibal]

Thanks for the answers.

One more question: is there any reason a Suzuki piston and seal rebuild kit (from a GS500 or GSX1100G) wouldn't work on a Kawasaki caliper? I tore down my Kawasaki calipers to inspect them and was planning to replace the seals and dust seals, but at least one of the pistons has some minor pitting. The Kawasaki piston and seal set is about $50 per piston ($100 per caliper), and the Suzuki set is under $40 per caliper. The calipers are identical (as far as I can tell), so the Suzuki kit should work in the Kawasaki caliper, right?