Twin Rotor/Brake GS Front End (77-81 Mag Wheels)

[AOD]

Since the "Wanted" forum doesn't allow people to post replies, I wanted to post this here. I'm looking for everyone's feedback, input, and help.

I'm looking to convert my single rotor/brake front end to a twin rotor setup. I need the entire front end from a twin rotor bike, including the wheel if possible.

I will take parts from individuals if someone doesn't have the whole front end.

I'm located near Asheville, North Carolina (28704) for shipping/pickup purposes.

~Adam[/b]

[robinjo]

The '81 2-v GS550L I have in my shop has a wheel that is equipped with mounts for 2 discs but one side has a cover over them. I also have a nice set of semi-floating slotted 1150 discs


Complete braking system actually of a 1150 with master cylinder, lines, t-piece and dual piston calipers but the mounting holes have a different spacing I think.

I was corresponding with a Dutch guy who owns a 550, a '79 I believe, with a warped front disc and made him take the measurements off his dic, disc diameter is 275 mm, heart to heart distance on the mounting holes is 40 mm same as my discs, still have to find out his disc's thickness ( he is off to Poland at the moment) but I think it will be 6 mm, how much is yours?

He didn't want the set of 2 discs but the rear one is the same as the front ones but 6 mm instead of 4 so that could be an option...

[AOD]

The single front rotor setup has a bigger diameter disc than a twin rotor setup, I believe. The thickness is between 6-7 mm currently, but if I upgrade to the twin rotor calipers, it may change - so I can't say right now.

I would consider your rotors, but I need to get a twin rotor wheel first to do some measurements.

~Adam

[robinjo]

Why do you need another wheel? :? Do you know for a fact that they are different or do you want/need to find out? I have a 81 Katana 1100 mag front wheel laying around to take measurement off if that is any good? 19" by 1.85" I believe, this is interesting fieldwork, I wanna say I helped!

[AOD]

Hey, I posted it in here for your help!

I can't remember if the Katana wheel is the same mag as used on the 70's and early 80's non-Katana GS's. Got a picture?

The reason I need a new/different wheel is because mine doesn't have the other rotor on it...nor do I have the hardware to install it.

There's an entire GS 1150 front end for sale on Ebay right now, but it used a different front wheel than mine. I'm not sure what the wheel size was on those bikes. There's also a set of forks from the same bike on ebay, but I don't much like the gold color. I could paint them...

~Adam

[robinjo]

Hey, I posted it in here for your help!

I can't remember if the Katana wheel is the same mag as used on the 70's and early 80's non-Katana GS's. Got a picture?

The reason I need a new/different wheel is because mine doesn't have the other rotor on it...nor do I have the hardware to install it.

There's an entire GS 1150 front end for sale on Ebay right now, but it used a different front wheel than mine. I'm not sure what the wheel size was on those bikes. There's also a set of forks from the same bike on ebay, but I don't much like the gold color. I could paint them...

~Adam

This is the same model as mine used to be, mine now has spoked wheels.
The only hardware is the bolts to hold the rotor on and the securing devices, and on the speedo drive side (IIRC) a ring with a raised edge.
Don't know where this set is from, probably my Kat.

[edit] my 1000S has the ring on the side without the speedo drive :? [/edit]



1150 has 16" front wheel, forks are spread more apart then the older bikes for the wider front tire, mine had a 120 tire. I still have the set of forks but they are a bit pitted and one of the damper adjusters is stuck so not good, no triple trees.

[AOD]

Okay, judging from the picture I can use a Katana wheel, as it's the same wheel used on all other other pre 83 mag wheel Suzuki's.

Some co-workers have informed me there's a very large motorcycle boneyard about an hour from here and that I should find all the parts I need there. I'm gonna plan to check it out soon.

~Adam

[AOD]

So, no one has jumped up really loud and said, "I've done this one my bike, here's what to do and what not to do!"

Has anyone out there done this swap before??

~Adam

[Hoomgar]

I'm about to do it to my 1000 buddy but haven't done it yet :?

[edbot]

Adam, I did this conversion to my 77 750 which had spoked wheels and a single disc on the left side. Luckily, I was able to find a non running 79 750 with mags and twin discs that I bought for $135. Everything swapped over with no real problems.

You are correct, the single disc is larger in diameter and thickness than the twin discs. Interestingly, the spoked hub on the 77 is drilled on the right side to accept another disc but I think your best bet is to obtain an entire front end, although, I was able to use the 77 triple tree and only had to swap the forks, wheel and right caliper.

While everything was apart, I had the wheels powder coated , relaced all the wheel, suspension and steering bearings and seals. I also rebuilt the calipers and master cylinders and installed stainless brake lines.

I don't know how much of this applies to your 550 but my experience was relatively painless, except to my wallet of course. If you have any specific questions that I might be able to answer, let me know. Good luck!

[ptm]

I'm curious why you want to go to a twin disc setup. I always assumed that the twin discs would stop the bike faster, but the owners manual for my 750 shows the stopping distance the same for the twin disc E and the standard single disc model. Is it easier to modulate? Better feel? Looks? Just curious...

[edbot]

I don't know Adam's reason but in my case the 77's fork tubes were pitted and the rims and spokes were in poor condition. When I found an inexpensive donor bike that had the parts I needed I decided to do it, and hopefully improve the braking.

[AOD]

My reason for doing this is stopping power...I feel the single rotor is inadequate and it just plain sucks.

Ed, were you the one I was talking to about getting a Katana 1000 speedometer and tach? I'm still looking for one.

~Adam

[edbot]

No, that wasn't me Adam. In fact, I'm still looking for a gsxr speedo to replace the one that broke at the rally.

[Macmatic]

Hey Adam!

How about that GS550 caliper mounting bolt spacing number? Can you still measure it for me?

Now that I think of it it might not be the same anyway. I'm brainpan engineering an '82 GS550 Katana that I don't have in hand yet and I'm thinking about new calipers from a later bike. I think the Kat is dual disc in front?

/\/\ac