Twinpot Brake upgrade on 78 Skunk

[WillKo]

I see you recommend F3 rotors and they require drilling using a jig, what exactly is being done? Are you opening up the holes? Would rotors from a SV650S work?

[Suzukian]

Honestly, this thread should be a "STICKY".

[salty_monk]

I see you recommend F3 rotors and they require drilling using a jig, what exactly is being done? Are you opening up the holes? Would rotors from a SV650S work?

No rotors from an SV650 will not work. Rotors from a CBR will work but they need a hub spacer behind them. The F3 ones need a new PCD or Bolt circle drilled between the original holes. The hub spacer is also the drilling jig.

[WillKo]

So the holes on the F3 rotors don't just need to resized from 6mm to 8mm they need to be redrilled entirely?

[salty_monk]

On the F3 rotors that is correct yes. There are some somewhat rarer F4 rotors that just need the holes enlarged but you still need a spacer to increase the offset away from the wheel.

[alke46]

Dan, PM sent yesterday.........

[salty_monk]

Back at you Larry!

[Ossipeelake]

Hi Dan,
I'm looking to purchase one of your front brake upgrade kits for my GS1000EC. I have wanted to do this conversion for years now and hope that you have a set of brackets still in inventory.
Please let me know, I am located in New Hampshire.
Thanks, Steve

[Ukcalling]

Is the need to change the discs the offset or swept area of the discs and where pads contact? Want to upgrade my calipers but have new discs on my gs1000g hence the question

Thanks Nick

[salty_monk]

Hi Dan,
I'm looking to purchase one of your front brake upgrade kits for my GS1000EC. I have wanted to do this conversion for years now and hope that you have a set of brackets still in inventory.
Please let me know, I am located in New Hampshire.
Thanks, Steve

I PM’d you Steve.

[salty_monk]

Is the need to change the discs the offset or swept area of the discs and where pads contact? Want to upgrade my calipers but have new discs on my gs1000g hence the question

Thanks Nick

Hi Nick - Both. The bigger discs also create more room between the caliper and wheel spokes.

[garyS-NJ]

The difference in performance is "night & day". Loads more power, loads more feel. Takes it to a 2 finger brake from a "oh Sh** grab a handful" stock brake.

I worked the rotor swap out about a year ago, first changed the G over about 7 or 8 months ago & have done a couple thousand miles on it.

To fit this swap.. you just need to get a kit from me, some CBR F3 Rotors & Some Kawasaki twinpot pistons.

You can probably budget:

$30 - $50 on calipers depending on rebuild status, Ebay skills (They were used from about 87 up to 97 so it depends what year you get. Al ot of early ones need new pin rubbers although seals are generally ok).
$30 - $40 on brake pads. (I actually got one set of calipers for $30 with a set of useable pads once...)
$50 - $100 on CBR Rotors (depending on your Ebay skills)
$110 - 120 for the brackets, spacers & bolts. Depending on location, how you send the money etc.

Takes probably 3 or 4 hours to do it the first time as you have to re-drill the rotors using a drilling jig etc.

Well worth the money & effort.

Dan

Wow I know I'm commenting on an old post but I just sent you a message Dan and long story short with your kits I bought years ago and concourse calipers and cbr600 f3 (I think f3). I opened up the rotor mount bolts and found they don't line up. So I have to center your mounting bolt spacer and drill 6 new holes... Ugg!!!! Is there instructions anywhere you might email me or a link? Wondering if the supplier bolt hole spacer goes inside or outside the disc.. also wondering if I still use my stock mounting bolt 6 hole discs.

[salty_monk]

You use the smaller 6mm holes to bolt the spacer onto the back of the rotor (preferably using shoulder bolts). You then plunge a 21/64 Drill all the way through the spacer & rotor spider. It's best done on a drill press if you can.

I then remove the spacer & "kiss" both sides of the new hole with a countersink to take any rough edges off (it's very important the back of the rotor spider is flat when you've finished otherwise the brake will pulse).

The spacer goes between the wheel hub & rotor

[gtem]

I haven't read through all 64 pages (yet!), but has anyone done any weight comparisons between a typical set of twin GS rotors and calipers and the new parts (together with the adapters, rotors, twin pot calipers etc)? I would assume there's a decent amount of weight taken off the fork, and that would be yet another non-trivial plus to the upgrade.

[salty_monk]

Yes especially if you use the lightest 7 rivet CBR Rotors, that's the biggest difference.
The adapter plus twinpot caliper is approx the same weight as the GS lump. I did do all the sums years ago, they are probably in this thread somewhere but I can't remember the difference offhand.