• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

1100 rotor sizes

  • Thread starter Thread starter Sflex
  • Start date Start date
S

Sflex

Guest
I am in the process of swapping the front end on my 83' 750t to a front end from an 83 1100 of some sort. The problem is that I cannot mount my calipers (from the 1100 front end) with the rotors that I have (from a spare 1980 750 wheel I had) the rotors seem to be about a mm or two too wide. I thought that the rotors were the same for the 750 and 1100 from 80' through 84' but apparently not. My question is, what rotors do I need? Are all the 1100 rotors the same (E, ES)? are other 750 rotors compatible? I would appreciate any help.

Thanks
 
I have rotors from a 1980 GS1000G & a 78 1000E if they are any use to you.....

I also have calipers off the G too. Rotor size is about 294 from memory, maybe 296mm. The wear limit on both is set at 4.5mm. The G's are slotted. The 78's are solid.

Dan :)
 
IIRC, the rotors themselves should be the same, but is the wheel different?

In other words, are the rotors spaced farther apart?
 
as brian said, i also think all the '80 and up rotors (and the calipers too i think) are the same so your prob is likely to do with the forks/wheel spacing
 
I see how one wheel could be wider than the other, and the outer tire diameter can be different, but how could the distance from the center of the axle to the rotors be any different from wheel to wheel if the rotors bolt up? Am I missing some kind of spacer between the axle fork? I have one in there and it looks normal.
 
The width of the wheel where the rotors bolt on may be different. With the wheel mounted to the motorcycle, straddle the front wheel and look straight down. How wide is the hub between your knees?

If you can, it would be best to use the entire front end from the donor bike so things will line up. Even though the brake calipers and rotors are the same between these models, the caliper mounting holes on the fork legs and the width of the wheel hub may be different. I believe there's more space between the fork legs on the 1100 front end.

I hope I'm not misunderstanding your problem here.
 
some 750s have smaller diameter forks compared to larger models
that would be one way how the things would not line up unless you're swapping the entire front end
 
I have swapped the whole front end, the only difference is the tire and rotors. Its not the width, the spacers seem to work fine. Its that the calipers wont fit over the rotors and attach to the mounts on the forks. If the calipers were about 2 mm less in diameter they would be fine. any suggestions guys?
 
Mock it up and give us a photo if you can. Have you mounted the caliper in the original position. Is the caliper on the correct side of the lugs on the forks. Compare both sets of forks and see what the differences are. Swap the old forks back in with calipers attached, it might let you see what you are doing wrong with the other set. Just grasping at straws here, but when the obvious doesn't work then you have to go for the unobvious (is that a word).
 
take the calipers off the brackets and take the pads out as well
try mounting first the brackets then the calipers
that might help figure out whats going on
 
I have tried mounting just the brackets and they bottom out on the rotors, its like the rotors are a couple mm too long. You guys are sure that all the rotors are the same size? Im stuck here.
 
Sflex said:
I have tried mounting just the brackets and they bottom out on the rotors, its like the rotors are a couple mm too long. You guys are sure that all the rotors are the same size? Im stuck here.
Click to expand...

All rotors are not the same size. Are your rotors the slotted ones. I have three different sizes of slotted rotors from memory. Whether they are just on bikes for OZ I don't know. Give us a picture. Measure your rotors for us. Are the mounting lugs on both front ends the same distance apart from each other and the same distance from the axle location. Give us some pics of both front ends, the front wheel and rotor, dummy up the front end for us. We need more info here. So we can help.
 
I think I might have latched on to something here. The 750T only had a single disc if I am correct. And Suzuki's habit was to mount a large disc on the single disc models. All the 1983 1100's had twin discs so going by this theory their discs would be smaller. Therefore the larger disc that is still on your original 750T front wheel is too wide to let the 1100 caliper sit all the way down to mount on the fork leg properly.

All the '83 1100s had twin discs and they all have the same part number. So there are no variations on disc size on the 1100s of that year. The disc off your 750T has a different part number, and this disc was never fitted to any 1100s. So I would suggest that your single disc (I am assuming that is what you have as we don't have that information) is larger in diameter than the 1100 discs which the front forks and calipers came off.
 
Last edited:
If you get the rotors off an 1100 they should bolt straight up to your 750T front wheel. No problems. BTW I have a CBR900RR front disc on my GS so all type of mods are possible.
 
I had a caliper mounting problem myself. When I pulled my tire to replace it 1 of my calipers was hanging up turned out the dust boot was not ment for the caliper it was 2 big and it filled up with junk. So I went to the bike salvage yard the next town over and asked for a caliper for a 1100gk, well when I went to put it on today it was to small ,with 1 bolt in it would just sit on the rotor. I brought it back and they told me the caliper I needed was for a 1000 not an 1100. Yet when I ordered the new springs the first set was for a 1000 yet they were to small in diameter so I got springs for an 1100 and they were the right size. So I'm not sure what went on, unless the PO changed the front forks which would explain why the fender only fit on 2 of the mounting bolts but the tube size was for an 1100. The bolt spacing is the same about 2 7/8" on center but the calipers were different with mine having a larger arc to them so were the rotors changed with the calipers ? The moral of the story is not being the original owners of most of these fine bikes of ours who knows what changes were made before we got them so assuming in my case everything is original turned out not to be the case. Not sure if this helps but it something to consider.
 
The two slotted disc sizes I have are 260mm and 275mm. I thought I had three different sizes, but could only find these two. Let us know what size you have on your front wheel.
Cheers.
 
Ok, all the latest reply's have really helped I think. I havent been using the rotor from the single disk 750t. Instead I have been using the rotors from a dual disk 1980 GS750. I am not sure their exact size, I will measure them this weekend. I was unaware that there were two different rotor sizes as I thought the 750's and the 1100's all used the same rotor size from 1980 through 1984.

Does anyone know the rotor size for a dual disk 1980 750? Because I think that if they are indeed 275mm's, then the 260mm rotors that were mentioned would be the ticket. Thanks for the help guys!!
 
You must log in or register to reply here.
Back
Top