Thanks for that, I had a look at the Stahlbus easy bleeders and they do look useful and like you said bleed valves should be like this! I'm ok with the time it takes to bleed with the current valves, but if they develop any issues or leaks then Im sure Ill replace with the Stahlbus ones! Regarding the reverse bleeding though, I'm sure this still won't work on this loop section between the calipers though as either side of that loop is still trying to move the bubbles downwards right?
Put grease round the base of your nipple. (fnarr fnarr). This helps prevent air being drawn in via the nipples thread.
I've never had a problem with forcing the air across the loop to the opposite caliper. Once that section is clear of any trapped bubbles, it's then plain sailing. I always reverse bleed from the LHS caliper, as it is the furthest point from the master. In addition I have a Stahlbus bleeder on there too (as well as the calipers) so any air is expelled through that point or visibly back up into the reservoir. The only downside as I said before, is if you are a bit ham fisted you will get fluid everywhere, so I mitigate that by literally covering everything in protective cloths and always have a jug of water to hand to wash down an area if the worst happens. I only ever need to reverse bleed if I replace any braking components or have to disturb a line, else I just use the speed bleeders to replace the fluid when it needs changing. I do sometimes use my vacuum bleeder, if I am not bleeding the system from empty but I've only ever found them to be a bit of a faff and conventional bleed valves, never really work well when used in conjunction with a vacuum bleeder as they always admit tiny amounts of air via the threads when you crack them open or maybe I am doing something wrong! In any case I'm glad I binned them. Hope you get it sorted.
The brakes on your steed will be way good enough. Maybe just need setting up. But they don’t have to feel super solid
Great tip thanks, I may have a leak somewhere as I seem to have bubbles regularly in the braking system Yea I used to have the same problem when using a vacuum bleeder, it would always suck in air from the thread and make it look like there was loads of bubbles in the system! It feels annoying but I guess you're right I'll get the bubbles out and just live with the rest of the spongyness!! Ahh sorry not after, it's before every track day, I just do it as precaution. There's usually a few months between my track days and I used to notice brake fade during a TD and seem to regularly get bubbles in my brake lines which I purge just before a TD now. While the bleed hose is fitted I just end up replacing the fluid anyway, probably excessive, but while the bleed kit is fitted it's not much extra effort just to get fresh fluid in there too! So I had some time to bleed the brakes last night. Bled once using the factory method and got a few bubbles out. But then I bled again after holding up the LH caliper higher than the "loop" for a while and tapping on the line, and I got a few more bubbles out! I'm not sure how much difference the removal of that extra air would make but I'm sure it's better to be out!
I have a vacuum thing. The trick is not to create too much of a vacuum. You only need a smidge to draw the fluid through. If you use too much differential pressure it will draw air from everywhere it can. Just a smidge or one pump is good enough.
I know a Multistrada is a completely different machine but the principal is the same. I recently zip tied both break levers down and must have left them for about a week. The difference was unbelievable. After a day or so’s riding they were both noticeably softer though. Fresh fluid in there too. I’ve tried a speed bleeder on the rear, which does make life much easier. I’ve tried reverse bleeding and the crazy priced Castrol brake fluid. I’ve also had race lines on a previous bike. If I were you, for a track bike I’d fit the race lines. Motul fluid, speed bleeder on the rear, bleed it as you do for every track day and zip tie your levers until you take the bike out of the van at the track. You’ll definitely get a result from shaking any microscopic air bubbles up the lines during travel to the track. I presume you’ve fitted Serie Oro discs and softer pads? I have on my Multistrada and I’m very pleased. The rear actually works but I’m still not convinced it works as well as the rear brake on a bloody GS! Try the zip ties, even overnight. I’m thinking of doing it after every day I use the bike. Costs nothing and is dead easy.
I've heard of tieing down the levers, but I don't understand how it works to improve the brakes? I'm sure I tried it once and the lever was harder for a while but like you said, it was soon back to being softer. My system is mainly stock 1299 except for SBS RS pads and RBF600 fluid, since doing the LH caliper raise and bleed trick my lever feel has been better, and on my last ride out I purposely activated the ABS a few times and then bled again and it's improved it further. Im pretty happy with the brakes now, then aren't rock hard, but they aren't as soft as they used to be and I can't pull them back to the bar anymore before the rear wheel is lifting. Just need to test them on a track day now and try and do more thorough bleeds more regularly. I guess small bubbles just get every where over time. When it is time to change them though I will be looking at the valves, race lines, series oro discs and maybe a new M/C!
As I understand it, when you tie the levers down this compresses the fluid which in turn permits any air held within the fluid to 'condense' out. Additionally this air and any other air is forced to its end point. Ie the calipers. Then you bleed that air out. The fluid under normal atmospheric conditions can hold x amount of air, but under pressure this may be x/2. I think this is the principle.
Thanks chaps. I think one concern I had with this method was regarding leaks, if there is somewhere air is getting in, then surely putting the system under a lot of pressure for an extended period of time could lead to a fluid leak. Also, not sure how it would affect any seals? Would it be best to pressurise it only slightly?
Well I’m not sure about that. If you have a break fluid leak..you’re fkd. All I can tell you is when I zip tied both brakes for a week, yes a week, although overnight may have been pretty much as good, they were markedly better. As I understand it when you zip tie them the microscopic air bubbles are able to travel up into the master reservoir and out of the fluid. Hence better braking. It’s not a small difference it’s really noticeable. I’ve bled the brakes until there’s definitely no visible air bubbles. On the Multistrada whatever you do fairly quickly the rear brake turns to mush. This is because the brake line is routed too close to the exhaust and heats the fluid. I have concluded that on the Multistrada it’s going to be a constant battle unless I replace and reroute the rear brake line. In the mean time I’m going to try the Motul 660 as it’s a fraction of the price for the Castrol brake fluid. I’m going to bleed it every month via a one way bleed valve and I’m going to zip tie regularly. Either that or I’m going to buy a new bike. Trouble is there are no bikes whatsoever that tick all my boxes and make my heart rate increase. Damn.
All Ducati's (probably all) suffer from a terrible rear brake ime. The M/C is shite. Plus you pretty much have to remove the whole assembly to bleed it correctly. Ive gotten used to this over the years. Since I bought a 916 in 2000. You can buy a heat sleeve for cables and pipes if it is that troublesome. https://www.oldhallperformance.com/heatshield
I disagree sev, the mc is shite. My 916 is on its 3rd one. My 1198 was on its 2nd. The 1299 is still on its oem tbf. I agree its location is primary suspect tho. I consider the rear mc to be on a par with oem clutch slaves. Fit only for replacement at earliest oppurtunity.
Used to see a lot of track riders put strong elastic on their levers between sessions...same reason I guess though never tried it myself
A newer one lol https://www.oldhallperformance.com/heatshield-products-hose-protection/hot-rod-sleeve this may work
I've put a clamp on the brake lever this evening, I'm gonna give it a few days and then bleed again and see if it helps further
