Putting An ABSII Front End On A Standard ST1100

Uncle Phil

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Well, I've finally started this project that I have been talking about for years. The front brakes on the ABSII are quite a step above the front brakes on the standard. I have accumulated hopefully all of the parts I need to complete this project. I decided against installed the linked portion due to the additional plumbing and having to change out the rear master cylinder, caliper, and possible the hub. I'm doing some other 'refurbs' to my 97 Standard, RedBird, while I have her down. She's got the ABSII dash surround now where the turn signal indicators are halfway down the face instead of up in the light bar (required a little wiring 'mod' but no big deal). All the bodywork has been removed and some replaced. So far, I have the new ABSII steering stem installed (switched the ignition switch from the old one) with new CBR bearings, have the ABSII fender brace partially installed, and the ABSII forks (43mm instead of 41mm) in place. Now I've got to drag the ABSII front calipers, front master cylinder, various plumbing, and the ABSII front rotors out of my garage attic and prep them. Then I have to sort out removing the SMC and plumbing to the center piston on the front calipers that are usually triggered by pressing the rear brake. When I'm done, she should be able to do 'stoppies' with little effort! :biggrin:
 
This indeed will be an interesting project to monitor as it comes to fruition. As an owner of an ABSII I do appreciate that stopping power this mod will provide.
I wish you much success with the project.
 
You may need to check that the steering lock can still engage with the different triples Phil. I put a set of 43mm triples from a later model VFR800 onto my 1999 VFR, and while the ignition bolted right into place, the vertical alignment was a little off and I had to shim the ignition/lock mechanism downwards by 3mm so that the locking pin would engage with the socket on the steering head. Having said that, I'm guessing the frame is identical whether or not it is the ABSII or not, so maybe that won't be an issue for you. Good luck!
 
I decided against installed the linked portion due to the additional plumbing and having to change out the rear master cylinder, caliper, and possible the hub.
Phil, a question: Doesn't the rear sensor have to pick up a signal that the rear wheel is turning?
 
Well, I've finally started this project that I have been talking about for years.
By 'standard' is at that ABS I or no ABS atoll. If the latter, then that would be ABS on the front brakes by not on the rear? Does that not pose some odd braking dynamics or is that the case with ABS motorcycles anyway?

:bigpop: :bigpop:
 
Phil, a question: Doesn't the rear sensor have to pick up a signal that the rear wheel is turning?
The sensor is only to send a signal to the ABS computer and Traction control, since UP is only installing the ABSII front brakes and not the ABS computer the sensor is not required. That's my understanding.... ;)
 
I thought the ABS knew when a tire lost traction by comparing its speed to the other wheel.

How do it know?
 
I thought the ABS knew when a tire lost traction by comparing its speed to the other wheel.

How do it know?
That is correct. The ABS models have a tooth ring on each wheel. the sensors pickup the pulses from the tooth ring and compare front and rear. Apparently when the ST ABS system came out it was the most sophisticated in the industry, rivaling Porsche and Bosch.
 
I looked at the entire ABSII system (and I have all the parts including the additional wiring harness) but it's just too much sugar for a nickel to do the whole thing. It involves replacing the fairing stay, the rear 'chunk', the rear caliper, the rear wheel, install all the 'back and forth plumbing (pumps, etc.) , all the relays and electronics (besides all the front end stuff) and then hoping all the parts you got will work together. My plans are to 'plumb' the middle piston into the 'braking' hydraulics with the other pistons. The only 'real' way as I think Techtony(?) found out on his ST1300, would be to have both bikes side by side - and move it over one piece at a time. I just want the vastly improved stopping power of the ABSII calipers and master cylinder and the thicker forks with the 'built in' fork brace. If you've never ridden an ABSII ST1100, you cannot believe how much better the brakes are - not the ABS, just the brakes. You have about twice the pad area on the ABSII and much more aggressive pads.

Not really much picture wise so far, as it's the same drill as changing out the steering stem bearings other than moving the ignition switch to the new triple tree.

TerryS - Good catch on the lock - I will check that out before I proceed with the plumbing.
 
On the ABSII the brakes are linked, so is it not just one extra pot the front has to move? Currently the front system moves 4 front and one rear, correct? The rear pedal moves two rear and two front.
I also believe the reservoirs are the same capacity between the ABS models and the standard.
Curious....hmmm I need to look at my service manual.
 
It's interesting to consider - since the 'normal' ABSII LBS moves 5 pistons (4 front 1 back) with front lever applied and the way I set it up is the front lever moves 6 pistons up front, it will be interesting to see how the fluid level sorts out. I figure if there are issues, I'll just 'cap' the middle pistons and call it good.
 
Moving more pistons with the same master cylinder would certainly change the feel the travel and the effectiveness of the lever at any position. More granularity without the benefit of full travel stopping of the original setup.

I added a front caliper to my 750 to make it a dual disc bike and the lever easily went to the grip. The bike still rolled with a hard push. I didn't try riding it much if an all IIRC. I swapped out my Honda MC/lever assembly for that of some Yamaha with dual discs and everything worked and felt sorted.

'Capping' the extra piston would be the most expeditious route. Finding another MC/lever assembly that gave the proper performance seems like it would be an educated trial and error ordeal.
 
On the ABSII the brakes are linked, so is it not just one extra pot the front has to move? Currently the front system moves 4 front and one rear, correct? The rear pedal moves two rear and two front.
I also believe the reservoirs are the same capacity between the ABS models and the standard.
Curious....hmmm I need to look at my service manual.
I generally doubt the myth of "ABS-II system has more brake power/performance"...
During an MSL course we'd a friend's ABS-II/CBS competing with my non-ABS...
Guess what: within several runs from various speeds the non-ABS stopped 3~6ft earlier then the alphabet soup... OK, dry tarmac, no obstacles and that...
So methinks that this all roots on the idea/concept of the rear brake pressure assisting the front (as their ABS one could just hammer them, whilst I on the non-ABS have to apply some analogue smoothness...)

There might be the issue of easier access to 120/70 over the 110/80 bias-ply tires in some places, OTHO is that 120/70 radial bigfoot notorious for catching on just any longside groove, tire-tracks, yet even whitelines potruding just a few millimeters, slowly creeping all over the lane while running on flat deck, spongy, unprecise steering feedback, increased steering forces, "popping" the bike up vertical upon just over the shier thought of using the brakes while leaned, yet actually using the levers...
 
I generally doubt the myth of "ABS-II system has more brake power/performance"...
I have 3 of the ABSII and 1 of the Standard and quite a few miles (300,000+ miles) under various conditions on all 4.
I'll take the stopping power of the ABSII (without the ABS) all day long over the standard.
If you have a chance to study the two systems, the front pads on the ABSII are much more 'aggressive' to me (ridges versus flat surface) and have significant additional pad surface compared to the standard front pads. (I have both so I have compared them more than once). I think it is just a matter of physics that more pad contact surface would mean more braking. I am by no means an engineer but I am doing this project based on my experience over many miles. BTW, I have run an ABSII front rim on my standard for years so tires are not an issue. It fits fine with no clearance issues, you just have to swap the discs. I do wish there were a lot more ABSII front fenders out there as they seem to be made of unobtanium now - especially in the arrest-me-red color. :biggrin:
 
I'll take the stopping power of the ABSII (without the ABS) all day long over the standard.
Will have to take your word for it :biggrin:
If you really omit the CBS and install the front master only, you might gain a better pressure point though...
With all the plumbing attached the CBS brakes are always on the spongy side IMHO...
 
I think Phil has my notes on this but I'll throw this out there for entertainment.

Theoretically, increases in braking performance from the ABSII lever/caliper combo will probably be lost by the disc smaller diameter having less leverage to stop the bike.

If power equals the ability to lock up the wheels, then there is no difference between the standard an ABSII. Opinion based on many miles of riding both ST1100 models.
But, realistically, the way the input from your hand lever is applied by the system results in a quicker response with less effort from your hand because there is the secondary master cylinder adding braking power to the effort from your hand.

The initial feeling of switching from standard to ABSII is that the ABSII stops a whole lot faster.
Once I ramp up hand effort I'll reach the same amount of braking power. During that ramp up in effort difference between standard ABSII there has to be some difference in stopping distance even the braking power is ultimately the same, the ability to lock up the wheels. That difference in distance might be inches or could be feet depending on how well attuned one is to the bike.
My other experience with linked and not linked is with the VFR800 and ST1300.
Delinking the VFR and plumbing to all six front caliper pistons resulted in way too much travel. Since I drilled the calipers I got a CBR600Fsomething master cylinder to make the piston ratios the same as the stock VFR lever plumbed to the original four outer pistons.
It brought up the consideration of what variable modulates stopping a bike, brake lever travel distance (very little change in effort) vs stopping with hand effort increase (very little change in lever travel).
Somewhere there is a balance.

With the ST1300 I went straight to simply removing the plumbing to the center pistons. (rear gets all three plumbed together)
The difference between the linked and unlinked 1300 is similar to the difference between the standard and ABSII 1100.

Based on the VFR experience, I want to test plumbing in one front center piston on the 1300 to see if that balances the ratios more favorably or not.

Phil, I figure you'll find 6 piston too much.
It will be interesting to see if 5 works better.
If 5 is too much it would be certainty be better than 6.
Also if 5 pistons is too much with the ABSII master cylinder, then using the standard master would put the ratios in the right direction.
Although some combination above might work better or not, using four pistons with the ABSII master is going to work fine.

Now if capping the center pistons turns out to be the solution, it is standard procedure in the land of delinked VFRs and Blackbirds to drill a small hole in the bleeder so there is no chance of air expanding and pushing on the piston.

And this is what happens when I run out of :bigpop:
 
QUOTE
I generally doubt the myth of "ABS-II system has more brake power/performance"...
During an MSL course we'd a friend's ABS-II/CBS competing with my non-ABS...
Guess what: within several runs from various speeds the non-ABS stopped 3~6ft earlier then the alphabet soup... OK, dry tarmac, no obstacles and that...
So methinks that this all roots on the idea/concept of the rear brake pressure assisting the front (as their ABS one could just hammer them, whilst I on the non-ABS have to apply some analogue smoothness...) QUOTE

This has been noted several times in moto mags. Maybe so with a cool, calm, collected rider on a "clean" closed course. Riding in the rain, a damp road, or during a panic stop, the usual response is to hit the brakes hard. The ABS works in the panic stops without locking the wheels. Numerous guys have agreed with the ABS is better without going into the ABS mode. Several guys have swapped master cylinders to change the ratio of the master to slave cylinder ratio. The comments were positive. I think Honda simply "whoopsied" on their choices for the front brakes on the non-ABS system. It works but not as good as it could.


QUOTE
There might be the issue of easier access to 120/70 over the 110/80 bias-ply tires in some places, OTHO is that 120/70 radial bigfoot notorious for catching on just any longside groove, tire-tracks, yet even whitelines potruding just a few millimeters, slowly creeping all over the lane while running on flat deck, spongy, unprecise steering feedback, increased steering forces, "popping" the bike up vertical upon just over the shier thought of using the brakes while leaned, yet actually using the levers... QUOTE

I don't know what "bike/tire/pressure" you're running but in my several hundreds of thousand miles of ST1100 ABS riding (several different bikes) I only noticed this in 2 situations. One was low pressure in tire. The other was when my new tire started to weave around big trucks or busses at 50 mph or higher. I was running a Dunlop of one type or another. Tried different air pressures and rear shock settings. No joy. I tolerated it for about 1500 miles and was replaced. It was relegated to an emergency spare status and finally trashed.
 
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