Front Rotors

[red bandit]

The front rotors on my 79 standard measure 11 3/4" in diameter. The ones I just got in the mail are supposed to be off an 81 with slots but they measure 10 1/2". Don't all the xs11's take the same dia. size? And any idea what bikes take 10 1/2's?

[DGXSER]

The slotted rotors were only on the specials, I think the 79's still had solid on the specials though.

I thought they were all the same size as well.

[oldnortonrider]

Front rotors on my '81 Special measure 11 3/4"; with slots.
Back rotor with slots > 11 3/4", also.
I'm thinking, "10 1/2" rotors don't go on any of the XS11s; front or back, slotted or unslotted. (?)

[Cobia]

Could those smaller ones be from a smaller XS? Like a 450, 650 or so?

[rman]

I think that the XS650 is the same size as the XS1100. I think that the XS750 uses the 10 1/2 inch rotor.

[fredintoon]

Too late for Eric

You can get 10 1/2" slotted rotors? My son Eric and I recently spent a whole afternoon drilling all 3 of his XS750 rotors in a pretty swirly pattern. If only we'd known.
FYI XS650 one-piece front rotors are a straight swap for XS11 rotors and many XS650 riders seek out XS11 slotted rotors rather than drilling the super-tough Yamaha rotor alloy. XS650 rear rotors are smaller, the same diameter as all 3 of an XS750s rotors. Any idea which particular Yamaha donated those slotted disks?

[red bandit]

From what I've found the 750/850 use 10 1/2" rotors and they are the same thickness as the 11's, 7mm. I think the 850's had slots, maybe only the later one's, not sure on that. The one's I have are 5mm thick, I have no idea what bike they came off of. They are in good shape if anybody wants them.

[Schming]

The rotors You described are probably off of an XJ650/750 Maxim. My XJ 750 Mid Max is at another location right now or I would measure to be sure but I'll get the dimensions and get back to You ASAP

[Silent]

The slotted rotors were only on the specials, I think the 79's still had solid on the specials though.

I thought they were all the same size as well.

My '79 Special has 11 3/4 non slotted rotors.

[b.walker5]

My 80 Special has no slots on front but does on rear, so I'm thinking some PO has changed them for some reason. Probably stacked it at some stage.

[Geezer]

Yahman and I have been working on a rotor design that I'm trying to get produced.

Here's a pic of the preliminary drawing. It will have 24 6mm slots and be about half the weight of the original rotors.
http://www.oregonmotorcycleparts.com/omp_rotor.jpg

I'm also considering going with a thinner disk. The YZF-R1 Yamaha puts a lot more stress on it's front rotors and they're only 5mm thick as opposed to the 6.8mm I've found on all the XS11 disks I've measured.

I'm still waiting for a final estimate but they're going to come in at under $100 a disk. The big problem is I'm going to need to get orders in advance to do this. I'm going to do this as a group purchase and everybody will get their disks at cost.

Geezer

[b.walker5]

Cool

Excellent design dude. Up until now this used to be my favorite,



bikes not bad either, but I think I now have a new one. Cost will probably be a little high for those of us down this end of the world, but if you dont mind i'd like to take your design to a local machine shop and get it priced here.

[Geezer]

I was shooting for something with a classic look but with a touch of modern and I think I've nailed it.

The funny thing is the old single came CB750 takes the same diameter disk as the XS11 but with more offset, you can even bolt them up. So I'm looking to have different centers made and offer them to the 2 groups. The idea is to get the cost down as far as I can and still maintain quality.

I wouldn't mind having a Duck in my stable but I can't justify the price for as little as I'd ride a bike like that...

Tony

Excellent design dude. Up until now this used to be my favorite,
bikes not bad either, but I think I now have a new one. Cost will probably be a little high for those of us down this end of the world, but if you dont mind i'd like to take your design to a local machine shop and get it priced here.

[tinman905]

Yahman and I have been working on a rotor design that I'm trying to get produced.

Here's a pic of the preliminary drawing. It will have 24 6mm slots and be about half the weight of the original rotors.
http://www.oregonmotorcycleparts.com/omp_rotor.jpg

I'm also considering going with a thinner disk. The YZF-R1 Yamaha puts a lot more stress on it's front rotors and they're only 5mm thick as opposed to the 6.8mm I've found on all the XS11 disks I've measured.

I'm still waiting for a final estimate but they're going to come in at under $100 a disk. The big problem is I'm going to need to get orders in advance to do this. I'm going to do this as a group purchase and everybody will get their disks at cost.

Geezer

I'll take a set when you're ready to place the order.

[Geezer]

When it's getting close to order time I will post a new thread about the project with all the info.

Geezer