Hey guys, so recently I put an Ohlins inverted front end and dual disc setup on my 2014 Street Bob. Because my bike has ABS I had to have custom wheel spacers made for the right side, and have the ABS sensor machined down for the left side. Now that I've got everything back together it appears that I'm not getting ABS at my front wheel as I can lock it up. To compound that situation, the ABS is still kicking in on the rear brake, but the pulsing that I feel back through the brake pedal and bike is quite violent and feels like it's activated fairly easily.

Here are notes on the work that I did to the bike. The master cylinder for the front brakes was replaced with a new Dyna Low Rider master cylinder to accommodate the dual discs, the brake block was ordered from Drag Specialties and is the pn that they recommend for a Dyna Low Rider as well. I am still using the stock spoke wheel, and did not change out bearings, so the white bearing is on the left side up against the ABS sensor. The calipers are Brembo monoblock 100 mm calipers. Once the system was all put together I brought it to the local HD dealership and had them bleed the system with their fancy tool that cycles the ABS module. From what I know about the function of the ABS system on these bikes, I feel that the functionality should still be preserved with this setup. The only things I can think of are maybe these calipers don't play nice with the ABS system? Also, on the right side of the wheel, where the bearing is not an ABS bearing, is there anything there that plays a role in the ABS system? Are there other components that I've forgotten to update that are causing the ABS not to work properly? One last thing, the ABS light is NOT on in my speedometer, but I know that the ABS is not working because I just went and locked up and slid the front wheel several times stopping from about 40 mph.

Thanks for any help or advice! I've also thrown in some pictures in case that's helpful.

The first two pictures are the left (ABS) side, the third is the right side.

 

The system wasn’t bled right. Still air in the system. I’m guessing you got new lines? Brakes shouldn’t be a problem I recently swapped my road glide special brakes for performance machine calipers and bled the abs with my scan tool. I had to get new lines for the setup and it took 2 times to get the air out the abs unit. I’d take it to the dealership you had it serviced at

edit: in sure the fact that you machined your abs sensor probably has something the do with it. It’s not responding to the wheel when you lock up the brakes!

 

I will take it back and ask them to bleed it again. I'm hoping that it's not from machining the ABS sensor, since it was the side which faces away from the wheel bearing that was machined down, and other kits like the one from Big Bear Choppers also tells you to machine the sensor in order to fit for wheel spacing.

 

I went to my appointment with the HD dealer today to have them rebleed the brakes, and these were their service notes:

"Tech tested ABS system and everything checked out fine. Tech then test rode the bike and found that the ABS is working, but not designed to regulate pressure for 6-piston calipers, only 4-piston, so when too much pressure is applied, it only bleeds off enough pressure for a 4-piston caliper, resulting in front tire skid."

Problem is, based on the pn of my calipers, and the two visible outboard cylinder areas I don't have 6 piston calipers, I have 4 piston calipers....

At least they didn't charge me anything, but I'm also no closer to an answer of what's wrong. Anyone have any thoughts?

 

Alternatively, is there anyone here who lives close ish to Salem, OR that has the scan tool to properly bleed the ABS or know of a Harley mechanic in the area that has one and can tell the difference between 4 and 6 piston calipers?

 

How an actual "Motorcycle Technician" could think those are six piston calipers is beyond me...

But I guess maybe there could be something to what they're saying, conceptually... My bike doesn't have ABS and I don't really know how the HD system works in detail. But maybe it's possible the Brembo calipers have a greater fluid capacity than OEM, resulting in something along the lines of what the dealer said... But I think that would be a pretty rudimentary way for ABS to work. In most automotive systems, the "bleed off" is based on a variety of things but largely on wheel speed sensors, which read what's actually happening, regardless of how much pressure has been relieved. Pressure is relieved until wheel speed is deemed correct by the ABS control module, in simplistic terms.

But unfortunately, I'm probably no help to you!

 

It might be good to double check to make sure that your distribution block was machined correctly and all the passages are open for the ABS to work.

Dave

 

After calling around to every Indy shop I could find within an hour of my house I ended up with 1 of 2 results every time. Either they didn't have the scanner to do a proper bleed, or they couldn't get me in for at least a month.

With that being the case I bit the bullet and went back to the HD dealership. The same service writer as the first time was there, and I told him that after his mechanic had made the 6 piston mistake I was going to try and go somewhere else, but it turns out nowhere else can do it, so now I'm back.

The mechanic apologized for making that mistake, they had someone else do the bleed this time around, and they charged me half price this time around ($40).

And guess what? It worked! Well mostly anyways. I noticed immediately that the front brake lever felt much firmer. I also did a few front brake only panic stops on the way home and I can definitely feel the ABS kicking in now. It seemed like I could still get the front wheel to skid a little bit if I was really hard into the ABS for a long period of time, but I'm going to consider it a win at this point in time.

 

Ok, 3 x to get it right? Wondering what changed between appointment 1 and 3....

 

Well the visits went like this.

Visit 1: they bleed the brakes and I leave thinking everything is gravy until later when I realize that I can lock up my front brake.

Visit 2: they tell me I have 6 piston calipers and that bleeding them won't fix it anyways, so they don't bleed it and don't charge me for anything. Very concerned about what type of mechanic could make such a mistake I didn't say anything and left to seek out an Indy shop.

Visit 3: after not being able to find an Indy shop that had the HD scan tool to bleed the ABS, I came back to the stealership and told them their mechanic was wrong about my brakes and I just need them to do a thorough bleed on the system. They apologize, have a different mechanic work on it this time, and finally, apparently do a complete job of bleeding them.

Before bringing the bike in the first time I had tried bleeding the lines as best I could at my house. My best guess is that maybe by doing that, that when they went to bleed it the first time they were able to pull fluid with no bubbles pretty quickly, and didn't get back to where some air bubbles were hiding in the ABS module.