'Full Floater' rotor setup

[Kurlon]

On my prior race bikes, I converted my brake rotors from 'semi-floating' to 'full floating' by removing the spring preload washers from the rotor bobbins. This gave me rotors that could also double as tamborines when off the bike, but more importantly minimized drag when mounted on the bike. (They also frightened people who weren't used to rotors rattling when pushing the bike around at low speed.) While I'm working through sorting the horrible pulsing rotor and waiting on part I had a thought... what happens if I don't use the preload springs with the XB's setup?

 

[Cooter]

The Buell race teams solid mounted the rotor for the same reasons. With the added benefit of better heat dissipation into the rim. I have been on both sides of a blue front rotor, haha. It makes a difference.

 

[Kurlon]

I’m just going to use a window washer pump and tank to setup a rotor sprayer triggered by the brake switch. No more overheated rotor issues.

 

[outthere]

I wouldn't worry about an overheated rotor unless you traveling at 'pro-level speeds. Those fellas went through lots of them. Unless you're going to a chain drive set-up top speed is limited. Hard to kill a rotor with a top speed of 135 unless abused.

 

[Kurlon]

So, to that, if all goes well, I will be racing a national pro class, and the goal is to go chain drive ASAP. The urge to R6 front end swap the bike is very strong, parts are super cheap, I've got calipers, a master and two sets of clamps from prior bad science work on hand, and some rotors...

 

[outthere]

^^and if you make a steering stem to fit make 2. I would also like one. The worst thing about the Buell front end is the urge to stand the bike up under braking when leaned over.

There are ERB rotors out there both used and new but the folks selling them think they're worth more than gold.

The issue with the chain drive is the tensioner unless the swinging arm is modified.

 

[Kurlon]

I've seen a couple modified swingarms, and the jaw dropping price to have one modified over in Europe... really hoping I can find a used one at some point. In the mean time, I have to run what I've got.

 

[34nineteen]

So, to that, if all goes well, I will be racing a national pro class

Not on that bike you wont. At least not competitively. Even in their hey-day XB's weren't ever known for being fast.

, and the goal is to go chain drive ASAP.

Cool (for a race bike)

The urge to R6 front end swap the bike is very strong, parts are super cheap, I've got calipers, a master and two sets of clamps from prior bad science work on hand, and some rotors...

Why? Unless you go to a later model setup (like BPF), the Showa setup on the XB's is pretty sweet for a factory setup. Even the springs are pretty good for an American sized rider. I would run the factory setup first before doing a swap. You may be surprised.
There is a setup guide in the service book (www.buellmods.com) to help get a baseline established.


Buell was pretty good about spec-ing these bikes from the factory. Usually any upgrades tend to be pretty costly.

Its not like my R3 track bike which has basically garbage suspension from the factory.

 

[34nineteen]

I've seen a couple modified swingarms, and the jaw dropping price to have one modified over in Europe... really hoping I can find a used one at some point. In the mean time, I have to run what I've got.

Good luck with finding a factory (chain drive) swingarm. They were very rare and costly even when they were available. I have a Uly swingarm if you want something to send off for modification. I'm sure someone in the US will convert one, after all where do all those extended swingarm 'busas get theirs?

Since you are building a race bike you dont have to have the oil in the swingarm. Harleys dont.

 

[34nineteen]

On my prior race bikes, I converted my brake rotors from 'semi-floating' to 'full floating' by removing the spring preload washers from the rotor bobbins. This gave me rotors that could also double as tamborines when off the bike, but more importantly minimized drag when mounted on the bike. (They also frightened people who weren't used to rotors rattling when pushing the bike around at low speed.) While I'm working through sorting the horrible pulsing rotor and waiting on part I had a thought... what happens if I don't use the preload springs with the XB's setup?

You may want to remove the rotor from the wheel (you can do this while its still on the bike) and clean out the floating rotor parts. A lot of times pulsing is caused by the floating setup binding (due to a lack of maintenance). I'm a fan of the floating setup myself, but agree with CoOter (dont tell him!) about going to the EBR solid mounting for the rotor, especially for a race bike. My XB will likely always run the floating setup.

 

[Kurlon]

The advantages of going R6 front end, any suspension shop worth anything knows them blindfolded, massive aftermarket for them, OEM bits are still readily available and in production. Parts for them are everywhere, wheels, rotors, internals, super easy to repair/etc from parts trackside due to them being so abundant. Additionally, with a tweaked fender mount setup you can quick change the front wheel without undoing the calipers at all, which is particularly handy when you're a one man team in the pits.

Now, that said, I do want to give the OEM setup a fighting chance, compared to most bikes I've jumped on it doesn't feel crazily undersprung up front though I likely will need a higher rate set of springs. I'm not making any judgements on damping at the moment 'cause 15yr old oil, 24kmi on the bushings, I don't think either end has been serviced so not fair to say the perf is lacking yet. I've also only lightly played on the road, will need to get on a track to really get a feel for things.

I have pulled the rotor (EBC, not OEM) and hardware, and cleaned with scotchbrite and brake clean. I've got new pads on the way, will tear it down again and this time the caliper will come apart and get a dip in the ultrasonic while I'm doing things.

As far as competitiveness, remember I'm going up against Sportster XR1200s, etc, so everything is relative. I'm going to be down on power compared to the Hammer 1275 kitted machines to start, but chasing power will be a winter project.

 

[Cooter]

It's obvious you know what you're doing and have enough experience to get on track safe/fun/cheap. Are the grids for "Air-cooled American" very big on the East Coast?

Ya, you'll pay for the few specialty parts you need to make the OE system viable today. I have OE rotors, all the way to a spare EBR race set-up, I could even source a chain swingarm but it's all expensive because of the rarity:upset: IMO, get out there and use what ya got for a few races, then you can decide what direction to spend your money on.

Converting a stock tensioner to chain is easy and super cheap. I never had an issue with durability once I added a set screw to the slot.

 

[Kurlon]

I've only raced LRRS/NEMRR at NHMS with any regularity, so my view of grids is pretty localized, at the moment there are only two riders I'm aware of playing this game under NEMRR rules. One's on an XB, the other has a tube frame Buell and a 1200 XR they seat bounce between. Even back in 2008 there weren't many doing it. I'm hoping with the subclass in Super Hooligan we see a resurgence, though with HD ending production of the engine, it's going to make that difficult.

 

[34nineteen]

The advantages of going R6 front end, any suspension shop worth anything knows them blindfolded, massive aftermarket for them, OEM bits are still readily available and in production. Parts for them are everywhere, wheels, rotors, internals, super easy to repair/etc from parts trackside due to them being so abundant. Additionally, with a tweaked fender mount setup you can quick change the front wheel without undoing the calipers at all, which is particularly handy when you're a one man team in the pits.

Now, that said, I do want to give the OEM setup a fighting chance, compared to most bikes I've jumped on it doesn't feel crazily undersprung up front though I likely will need a higher rate set of springs. I'm not making any judgements on damping at the moment 'cause 15yr old oil, 24kmi on the bushings, I don't think either end has been serviced so not fair to say the perf is lacking yet. I've also only lightly played on the road, will need to get on a track to really get a feel for things.

I have pulled the rotor (EBC, not OEM) and hardware, and cleaned with scotchbrite and brake clean. I've got new pads on the way, will tear it down again and this time the caliper will come apart and get a dip in the ultrasonic while I'm doing things.

As far as competitiveness, remember I'm going up against Sportster XR1200s, etc, so everything is relative. I'm going to be down on power compared to the Hammer 1275 kitted machines to start, but chasing power will be a winter project.

Good points. :eagerness:

On the caliper, you can remove the pistons for cleaning while leaving the assembly together. At one time I made some wooden blocks to hold the other pistons in place while I used air pressure to blow each one out individually, and manually clean the pistons and seals with a clean rag dipped in brake fluid. I've had great results doing this as most of my Buells have had sticky pistons in the front caliper.

I found that to work much better than the ultrasonic cleaner.

I'm assuming your bike has the 6 piston setup?


Concerning the 1275 kits, I've not noticed much difference using them in a Buell application. IIRC the 1275's have a little bit more compression than the stock XB pistons, so aside from that and the small displacement bump, I've not noticed much difference. I'd imagine the same for the XR1200 also.

On my 2016 XL1200CX, I did a 1250 kit with cams. The 1250 kit made a little bit of difference, whereas the cams made a lot more power than the stock W cams that came with the Sportster.

Keep us posted, this thread is very entertaining.

For now, I need to go heckle a forum member who is trying to sell his moms car on IG.

 

[34nineteen]

It's obvious you know what you're doing and have enough experience to get on track safe/fun/cheap. Are the grids for "Air-cooled American" very big on the East Coast?

Ya, you'll pay for the few specialty parts you need to make the OE system viable today. I have OE rotors, all the way to a spare EBR race set-up, I could even source a chain swingarm but it's all expensive because of the rarity:upset: IMO, get out there and use what ya got for a few races, then you can decide what direction to spend your money on.

Converting a stock tensioner to chain is easy and super cheap. I never had an issue with durability once I added a set screw to the slot.

You're a set screw.

 

[outthere]

I can see Buell running circles around an XR1200. I've seen a few wadded up with hotdogs at the controls. No ground clearance.