Double discs-what am I doing wrong?

[MAC10]

I am setting up a 78 GS1000 with double discs. The bike formerly had the large single disc on the left side of spoked wheels. Now I have cast wheels, and original double discs and calipers from a 78, and new forks with double disc mountings. I notice that when both calipers are installed, the tire will not clear the calipers when I want to take it off.

The new forks are E models, with mountings for double discs. The fork lowers are slightly shorter than the original 78 legs. The triple tree is the original one which came with the single disc forks.

The calipers align with the discs, and work. The fender prevents me from rotating the fork legs to allow the calipers to clear the tire. Duh.

Everything is stock for a 78 bike. No other discs will work anyway, as they don't align with the pads. Have I used the wrong triple tree?What have I overlooked?

 

[TheCafeKid]

I am setting up a 78 GS1000 with double discs. The bike formerly had the large single disc on the left side of spoked wheels. Now I have cast wheels, and original double discs and calipers from a 78, and new forks with double disc mountings. I notice that when both calipers are installed, the wheel will not clear the forks when I want to take it off.

The new forks are E models, with mountings for double discs. The fork lowers are slightly shorter than the original 78 legs. The triple tree is the original one which came with the single disc forks.

The calipers align with the discs, and work. The fender prevents me from rotating the fork legs to allow the calipers to clear the tire. Duh.

Everything is stock for a 78 bike. No other discs will work anyway, as they don't align with the pads. What have I overlooked?

Take a pic, sos i can see. I just did this on a 750. Had no problems. You're not trying to use two of the large singe discs are you? That wont work..

 

[MAC10]

Thanks for the quick answer. I am using two of the smaller diameter discs intended for a 78 double disc setup. The calipers are original to 78 double disc set. The single disc set up has the caliper in a higher position. The discs and calipers mate perfectly. The only issue is the tire won't clear the calipers to remove the wheel.

Can't post a pic yet. I will do so as soon as I can, tomorrow.

 

[Theo]

Aren't you supposed to remove the calipers when removing the wheel. Otherwise you'll run into the problem of the tire not clearing the calipers. Or am I misunderstanding what you problem is?

 

[MAC10]

That might answer my question. I have never had a bike with double discs. Does one normally remove a caliper or two to get the front wheel off?:hand:

If I am this naive, please forgive me. I am known as a technopeasant. That is one reason I like ancient Bikes.

 

[Theo]

That might answer my question. I have never had a bike with double discs. Does one normally remove a caliper or two to get the front wheel off?:hand:

If I am this naive, please forgive me. I am known as a technopeasant. That is one reason I like ancient Bikes.

Well the manual for my bike says to, and for my other non-suzuki bike it says the same. I've tried to cut corners and not remove them but then...you know the rest.

 

[MAC10]

Thank you Theo. I can live with removing one caliper, or maybe both, when I need to drop the wheel. They even use the same size nuts, so nothing lost but a couple of minutes

I don't feel so dumb now.

 

[Theo]

Thank you Theo. I can live with removing one caliper, or maybe both, when I need to drop the wheel. They even use the same size nuts, so nothing lost but a couple of minutes

I don't feel so dumb now.

No problem, just use some bungee cords or tape to support the calipers when you remove them from the forks. BassCliff put a picture of this when he was working on the bike in his rebuild thread. I'll try and find it.

 

[will61310]

Can it be done with the spoke wheel? does the black cover come off the other side of the wheel? I bought a 79 front forks, and brake system - master,discs,lines for my 78 - 1000, but want to keep the spoked rims..

 

[TheCafeKid]

Can it be done with the spoke wheel? does the black cover come off the other side of the wheel? I bought a 79 front forks, and brake system - master,discs,lines for my 78 - 1000, but want to keep the spoked rims..

Yes and yes.

 

[TheCafeKid]

If you put it on a bike Jack you don't have to remove anything. Not even the axle bolt just take the caps off the end of the forks and out she'll drop. You'll have to disconnect the speedo cable.

 

[BassCliff]

Hi,

No problem, just use some bungee cords or tape to support the calipers when you remove them from the forks. BassCliff put a picture of this when he was working on the bike in his rebuild thread. I'll try and find it.

Do you mean these?

Make sure your axle spacers are aligned properly. I had problems with a brake rotor hanging up in the caliper until I realized that I had a spacer backwards. Or did I have the left one and right one reversed? I don't remember. Just make sure you reassemble properly. Check a parts fiche to be sure.


Thank you for your indulgence,

BassCliff

 

[Theo]

Do you mean these?

Yup those are the ones.
Thanks,
Theo

 

[MAC10]

Thanks BassCliff, and Theo. The photos help a lot. Very cunning installation of bungees.

On my 78 model, I could not get the slotted discs in your photo to work because they would not align the pads with the braking surface of the discs. I had to use older unslotted discs to get the alignment. Is that caused because the slotted discs in your photo come from a 1980 or later model and don't work with earlier forks?

 

[mighty13d]

just remove one of the calipers. Easy-peasy. And TCK... if the calipers won't allow the tire and rim to slide out, (as it won't on my 850) you can't just pull the caps and have it slide out. The calipers will still hold it. That works on a single caliper though.

 

[TheCafeKid]

just remove one of the calipers. Easy-peasy. And TCK... if the calipers won't allow the tire and rim to slide out, (as it won't on my 850) you can't just pull the caps and have it slide out. The calipers will still hold it. That works on a single caliper though.

Wanna bet money on that? If you get it up high enough to be able to work the wheel, off the ground, it will come out. You can also spin the lower stancheons away from the wheel to let it clear the caliper ( Assuming you've removed the fender) Almost more of a pain than its worth, but i put the wheel back ON that way, so it will come out the same way. I suppose it would also depend on your tire width perhaps..

 

[tkent02]

I suppose it would also depend on your tire width perhaps..

and on brute strength and stubbornness, too.

 

[TheCafeKid]

and on brute strength and stubbornness, too.

LOL!!! Indeed... I can be a bit stubborn at times. I ran into a problem with the 750 where someone had GORILLA-ed the caliper bolts.. I was using a breaker bar and they still wouldnt come undone, i was afraid i was gonna break em. But I needed the jack for another project, and I needed the 750 OFF of it, so I had to get the wheel on.. Etc etc.

Couple days of some PB Blaster got those puppies undone, but by then, the wheel was already on..

 

[mighty13d]

Wanna bet money on that? If you get it up high enough to be able to work the wheel, off the ground, it will come out. You can also spin the lower stancheons away from the wheel to let it clear the caliper ( Assuming you've removed the fender) Almost more of a pain than its worth, but i put the wheel back ON that way, so it will come out the same way. I suppose it would also depend on your tire width perhaps..

no I wouldn't bet money on it, but by just pulling the caps off, mine wouldn't come off. I'd have to pull my fender to spin the calipers to the sides and, if I remember right, I couldn't get the brake rotors out from between the brake pads before the calipers hit anyway.

 

[Big T]

Mine's got the twinpot conversion with larger discs, but the principle's the same. It all just bolts right in