GS 1000 dual disc

[Big T]

I have a GS 1000C (wire wheel, single front brake) and I've always wanted to convert it to a dual disc using the stock rotor size.

The sticking point is a right fork tube with a caliper mount in the right place. Did any later dual disc model use this size rotor? The E model uses smaller rotors, and I want something that's different.

Any help?

 

[humhead]

The easiest option is to find a dual disc setup from a similar GS. Install the lower forks, mount the discs to your spoked wheel, change the master cylinder & bleed. (While you're at it, install stainless steel brake lines.)
Suzuki didn't make a bike with dual discs that are the same diameter as the single disc. The stock E model dual disc system will give you noticeably better stopping power. Stainless lines help even more.
Adding a larger disc, even if it were possible, would have a negative effect on handling.

Terry

 

[JayH]

That certainly would be a different setup. That would be something if you could get those 2 BIG rotors on your wire wheels.

Are you working/fixing up the FL bike you happened to find on your last trip?

 

[Big T]

The Fl bike is sitting next to the house while I work on making space in the garage.

It is identical to my 78, so that's why I want the big brakes! Doesn't sound like there's a fork available.

Don't forget to send me some photos of your 78's gas tank for reference

 

[humhead]

That certainly would be a different setup. That would be something if you could get those 2 BIG rotors on your wire wheels.

Yes it would, Something BAD!! Old UJM rotors are HEAVY. The single disc ones are the worst offenders. There's a reason Suzuki switched to thinner, slotted rotors in 1980 - lower unsprung weight. Those big old cast iron pie plate rotors
make the bike turn slower & ride harsher over bumps.
Here's a quote from the Cycle road test of the GS10000E.
"The EN model has not taken kindly to the extra 17 lbs. of unsprung mass. Specifically, It has been made rather sensitive to road surfaces, and that is true
of both its ride and cornering behavior."
The tester felt that the standard model was a better bike. Handling was the primary reason.
Mounting the thinner, slotted discs & dual calipers to your spoked wheel will give you improved braking with little or no negative effects on ride & handling.

Terry

 

[Big T]

Gee, Humhead, you really seem obsessed with the unsprung weight.
Do you think a disc, caliper and 4' of brake line weigh even close to the 17 lbs the E has?
Besides, with steel lines, Pirelli tires, Progressive springs, fork brace, Marzocchi shocks and 28 years to make it like I want that I'm that worried about a bit of unsprung weight? No chicken strips on my tires

Well, if no GS has the fork I need, time to measure up my buddies KZ

 

[humhead]

Gee, Humhead, you really seem obsessed with the unsprung weight.
Do you think a disc, caliper and 4' of brake line weigh even close to the 17 lbs the E has?
Besides, with steel lines, Pirelli tires, Progressive springs, fork brace, Marzocchi shocks and 28 years to make it like I want that I'm that worried about a bit of unsprung weight? No chicken strips on my tires

Well, if no GS has the fork I need, time to measure up my buddies KZ

Obsessed? no. Concerned? yes. I just wanted you to know that you will be spending a lot of time & money on a project that will leave your bike worse than stock. You say that there are "no chicken strips on your tires" All the more reason to IMPROVE your front suspension & brakes, not make them worse.There are many benefits to reducing unsprung weight. One of the most noted is that, 1 kg of reduction in unsprung weight is approximately equal to 6kg reduction in sprung weight. I haven't weighed a single disc caliper & rotor, but I'd be suprised if it wasn't close to the 17 lbs. mentioned in the article. It will be enough to negatively effect the handling of your bike. That said, it's your bike. You're free to treat it as you please.

 

[UncleMike]

Humhead,

Would you have any advice for converting my 750T to dual discs? I'm looking to improve my braking power, but don't want to fall victim to making my braking or handling worse, either.

Thanks,
Mike

 

[terry]

Gee, Humhead, you really seem obsessed with the unsprung weight.
Do you think a disc, caliper and 4' of brake line weigh even close to the 17 lbs the E has?
Besides, with steel lines, Pirelli tires, Progressive springs, fork brace, Marzocchi shocks and 28 years to make it like I want that I'm that worried about a bit of unsprung weight? No chicken strips on my tires

Well, if no GS has the fork I need, time to measure up my buddies KZ

I think a lot of that unsprung weight can be pared off with some disc drilling mate, I've got a 1979 GS1000SN with stock unventilated front discs and calipers, and a 1979 GS750E with a wire front wheel and dual unventilated discs (proto-type police bike) that a PO drilled, the 750 seems to handle and brake a little better than the 1000, and the 750 front wheel is certainly much lighter. I think the later calipers would work with the earlier discs too, even though the earlier discs are obviously thicker.

I do like the later (1980-on) front brakes though, my 1981 GS1000G and GS1000ST were the best braking bikes I had (well all I've got in my garage apart from the Suzy's are old SOHC Honda CB750's) until my ABS equipped BMW K1100LT came along, that thing is just incredible! Cheers, Terry.

 

[8trackmind]

It's not bad at all.
http://www.thegsresources.com/_forum/showthread.php?t=98098&highlight=Ninja+Calipers

 

[humhead]

Hey 8 track, I was looking at the EBC Brake catalog & noticed that they make replacemant rotors for single & dual disc GS 1000's. Thy're an improvement on the originals; they're "floating".
I'd be willing to bet they're lighter than any stock GS rotor. I like your idea of using the kawi calipers. I hope to go that route soon. I'll use the EBC dual disc replacements & fabricate adapters as necessary.
The EBC part numbers are MD 3014 (rear) MD3014 LS & RS (dual disc front)
MD 3020 LS (single disc front)
They also offer a custom rotor service. The details are on page 235 of their online catalog http://www.ebcbrakes.com/Assets/USA2006MCcat.pdf
Maybe they'll make a MD 3020 LS.....Or better yet, a hybrid rotor set that has the rotor diameter & shape of the donor kawi's rotors & the GS hub mount & offset.

Terry

 

[8trackmind]

I'm glad you can afford 'em. I can't. :-D