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79 bobber, different year forks?
- Thread starter warrenlevihursh
- Start date
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- Tags
- bobber model id suspension
Ok, A brief history lesson. The early bikes used 34 mm forks. The first year of disc brakes used a one year only disc set up. In 73 they used the same caliper but changed the disc mount to a bolt on disc.
They used this set up till 75, in 76 they moved the caliper to the rear of the forks.
In 77 they changed to 35 mm forks. They also changed from the earlier two piston solid mount caliper to a singled piston sliding caliper. They had to change the disc offset to match this new caliper.
They used this set up for the rest of the years XS650 were made.
Now knowing this you should understand that old parts won't interchange and work will new parts.
The calipers not only changed in the way they worked but the mounting holes were spaced differently. The early calipers, up to 76, had about 3 3/4 inches CTC. The later, 77 up had about 4 3/8 inch CTC.
In your pic you show a set of the early forks. The two tabs on the very bottom are the mounts for the fender braces.
I posted two pics, the first is the early style caliper. The second is the later caliper.
Those forks use the first one.
I don't think the rotor your pic shows will work with the early caliper. That rotor won't have the right offset. You need to space it out away from the hub.
To check those forks measure the CTC on the caliper mounts, 3 3/4 inches, and the diameter of the upper tubes, 34 mm. This will verify that they are the early forks.
Leo
They used this set up till 75, in 76 they moved the caliper to the rear of the forks.
In 77 they changed to 35 mm forks. They also changed from the earlier two piston solid mount caliper to a singled piston sliding caliper. They had to change the disc offset to match this new caliper.
They used this set up for the rest of the years XS650 were made.
Now knowing this you should understand that old parts won't interchange and work will new parts.
The calipers not only changed in the way they worked but the mounting holes were spaced differently. The early calipers, up to 76, had about 3 3/4 inches CTC. The later, 77 up had about 4 3/8 inch CTC.
In your pic you show a set of the early forks. The two tabs on the very bottom are the mounts for the fender braces.
I posted two pics, the first is the early style caliper. The second is the later caliper.
Those forks use the first one.
I don't think the rotor your pic shows will work with the early caliper. That rotor won't have the right offset. You need to space it out away from the hub.
To check those forks measure the CTC on the caliper mounts, 3 3/4 inches, and the diameter of the upper tubes, 34 mm. This will verify that they are the early forks.
Leo
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warrenlevihursh
XS650 Addict
Wow thanks Leo for the thorough reply. Yes they are 34mm and 3 and 3/4 on the mounts. I think the wheel and rotor is from a later year. I already have the caliber and mount for the later years, so i guess my best bet would be to just find the correct forks? Are these worth anything? They are in good shape and feel nice. Thanks again!
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That's an early two part disc you have there. It is a match for those forks and the old style caliper. The later discs are cast as all one piece. Here's a pic .....
Here's the old and new style compared. As mentioned, the offset differs (by about 5mm) so you need the right forks and caliper for everything to mount up and match .....
Here's the old and new style compared. As mentioned, the offset differs (by about 5mm) so you need the right forks and caliper for everything to mount up and match .....
warrenlevihursh
XS650 Addict
Thanks for the reply.
Ok well that complicates things. Are the wheels prob 72 as well then? Would i be able to use the newer rotor with those wheels if i bought newer forks? Maybe ill just say screw front brakes! So far i have an 81 motor, 78 frame and title, 72 forks and rotor.... Great...
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Ok well that complicates things. Are the wheels prob 72 as well then? Would i be able to use the newer rotor with those wheels if i bought newer forks? Maybe ill just say screw front brakes! So far i have an 81 motor, 78 frame and title, 72 forks and rotor.... Great...
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Hi warren,
don't sweat the wheel's age. All XS650 front wheels that have bolt-on brake disks interchange with each other no matter if they're wire wheels or cast wheels or what forks they originally came in. Gotta mix'n'match the disks to suit the caliper, is all.
FYI, they'll also fit XS750/850/1100s.
I'm running an XS650 cast wheel in my XS11 right now rather than swap out a worn tire.
[edit]
Your posts and photo say you have a 34mm fork and the wheel has the 2-part disk that goes with it.
Most likely all you will need to get a working front brake is the correct 2-pot caliper and the m/c that goes with it.
Now the nagging starts; those who say "screw the front brake" are those most likely to end up as a smear of forensic evidence at a collision site.
don't sweat the wheel's age. All XS650 front wheels that have bolt-on brake disks interchange with each other no matter if they're wire wheels or cast wheels or what forks they originally came in. Gotta mix'n'match the disks to suit the caliper, is all.
FYI, they'll also fit XS750/850/1100s.
I'm running an XS650 cast wheel in my XS11 right now rather than swap out a worn tire.
[edit]
Your posts and photo say you have a 34mm fork and the wheel has the 2-part disk that goes with it.
Most likely all you will need to get a working front brake is the correct 2-pot caliper and the m/c that goes with it.
Now the nagging starts; those who say "screw the front brake" are those most likely to end up as a smear of forensic evidence at a collision site.
warrenlevihursh
XS650 Addict
I just rerear xsleos reply and it seems the forks and rotor would be a 76 because it is a bolt on and the caliper mounts are in the rear?
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To confuse you some more.............If that pic is taken from the right side of the bike then the forks have been swapped from side to side. The axle clamp is situated on the left side of the bike and the fork for that side has a stop that protrudes for the speedo to sit in.
The fork, in the pic, has had the mount for the brake line removed.
To help with ID'ing the bikes have a look at the pics of the different models HERE
The fork, in the pic, has had the mount for the brake line removed.
To help with ID'ing the bikes have a look at the pics of the different models HERE
warrenlevihursh
XS650 Addict
I was only kidding about not doing a front brake. I would never ride without one. My brother did for about a year and i finally got on him enough to get one.
Ok, so is the caliper Mikes sells complete or is there a seperate bracket i need? It looks like its all in one?
Thanks for all the help!
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Ok, so is the caliper Mikes sells complete or is there a seperate bracket i need? It looks like its all in one?
Thanks for all the help!
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warrenlevihursh
XS650 Addict
Ok well 650skull has a good point. Yes its from the right so that means the caliper should actually mount to the front of the forks once i swap them around, which ill go do now. So they arent 76's afterall...
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74TXA/75XSB. Same size 34mm forks as the 76C.
The PO has done some de-tabing of the forks. If you intend to run without a speedo the forks can stay that way around. The Euro or English 75XSB actually done the fork swap and had extra Brake line tabs mounted on the forks and the speedo tab was an extra on the swaped fork as well. This was only a Euro thing and not on the US or Oceania models
The PO has done some de-tabing of the forks. If you intend to run without a speedo the forks can stay that way around. The Euro or English 75XSB actually done the fork swap and had extra Brake line tabs mounted on the forks and the speedo tab was an extra on the swaped fork as well. This was only a Euro thing and not on the US or Oceania models
warrenlevihursh
XS650 Addict
Yes 650skull, #8 is true. And i cant swap them around because the other side has no mounts, unless i swap the rotor and run a left side only rotor.. Thats pretty weird. I dont know what is going on with these things. I really wanted a springer, seems like a good excuse now, only prob is using stock wheels with those.
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warrenlevihursh
XS650 Addict
Im not doing a speedo so ill run the forks as is i guess. So it wont be an issue having the caliper mount on the right but in the back right?
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Hi warren,
or, you can swap the fork legs back to where they originally were.
Unlike the later one-pot calipers which are handed so you'll need a leftside one from an XS750/850/1100 Standard to run a leftside disk the stock 2-pot caliper can be reassembled t'other way round to work a leftside disk OK.
I seem to remember that the bleed nipple ain't in the optimum place on a transmogrified caliper but it'll still work.
or, you can swap the fork legs back to where they originally were.
Unlike the later one-pot calipers which are handed so you'll need a leftside one from an XS750/850/1100 Standard to run a leftside disk the stock 2-pot caliper can be reassembled t'other way round to work a leftside disk OK.
I seem to remember that the bleed nipple ain't in the optimum place on a transmogrified caliper but it'll still work.
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No problem at all. Just need a spacer for the speedo delete. Actually it doesn't matter what side the rotor mounts to, the hub has provisions for twin disk, under the stainless cover, as in other countries. US models were the only country not to have twin disks from 76 and later.
warrenlevihursh
XS650 Addict
Thanks guys, ill let you know what route i go.
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warrenlevihursh
XS650 Addict
Alright- i ordered a pair of 77 forks from ebay and an 81 front rotor. Believe it or not, that was cheaper then buying Mikes caliper for a '75. Im in about $87 including shipping for everything. Im sure the forks will need some work, but i already have a nice bracket and caliper plus these are nicer brakes in my opinion. Thanks for the help. Now im wondering what to do with the 74-75 forks i have?
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You'll need the triple tree for the '77 35mm forks. Your current forks and triple are for 34mm.
'77 and newer forks and triple trees are 35mm.
But the bike is a '79 or '78.....nuts. Yeah, project.
'77 and newer forks and triple trees are 35mm.
But the bike is a '79 or '78.....nuts. Yeah, project.
warrenlevihursh
XS650 Addict
I was thinking about that. I think (hope) the ones on it might be for the 35mm but im not sure. Ill mic them when i take the old ones off. I really dont want to buy all that as well.
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warrenlevihursh
XS650 Addict
I may see about opening them up as well. Did anyone ever do this? It would only be a 1/2mm around the circumference, so it doesn't seem impossible. I'm only thinking about this because all of the eBay ones are junk and over-priced.
