Yet more brake bleeding problems - resolved

I've replaced the pistons and seals in my front calliper (and pads).

Right-hand/ front system bled quickly and efficiently. Very solid feel.

Left-hand/ rear system is being the usual obstreperous unbleedable unmentionable. I'm using a vacuum and have worked a couple of times around the rear and lower front bleed nipples. I've put nearly a litre of DOT4 through it with no air coming out and no sign of a proper brake lever. I'm not doing any more of that until I understand what's going on.

My conclusion is that there's an undocumented trap for air somewhere in the system and that some engineer, thinking that just because he worked for Honda, he could direct water to flow uphill. As a Canadian actor once said in a funny voice, 'Ye canne change the laws of physics'.

I suspect that somewhere around the delay valve there's a bit of silly design. Alas, that's inside the plastic somewhere and I'm not familiar with it. Has anyone looked at this and might there be an air trap there?

The Search window (Advanced / Google) produced this interesting discussion: 

https://www.silverwing600.com/t4516-how-can-the-brake-delay-be-tested

I took my wing to my local garage who charges very little for a bleed. It has improved the brakes quite a lot and manage to lock tyres now before the lever hits the grips.

Once the new disc is on, that will improve the front brake further as a warped disc will push the pads out further an

Much better than me cursing and mucking it up.

Hmmm… How do you lock the tyres/wheels on a Silver Wing equipped with ABS as a safety feature to prevent the rider doing just that?

I never managed to lock up a front or rear wheel up once in my eight years of Silver Wing ownership.

Try bleeding it through the traditional way rather than using a vacuum thingy.

Meldrew. ABS will not stop a wheel locking up. But will prevent it carrying on.

I don't know how old your SW is but rear brake bleeding has haunted me for six years, even though mine doesn't have ABS. It took a whole lot of piece-by-piece elimination to get my rear brake to behave properly; it's all covered here on the forum, including the brake delay valve.

I ended up replacing a ton of stuff and get the brakes bled at the shop. My brakes are the best they've ever been.......kinda scary when I think about how many miles I have covered with imperfect brakes

On Page 70 of the Owners Handbook, "the ABS is designed to help prevent lock up during hard braking on uneven or poor road surfaces while running straight. Although the wheel may not lock up, if you're braking too hard in a turn the scooter can still lose traction causing a loss of control.'

Unlike your old Forza the Silver Wing is also equipped with a Combined Braking System. The front brake lever applies the front brake, Operating the rear brake lever applies the rear brake and a portion of the front brake.

Can't say I miss my Silver Wing at all, although I was pleasantly surprised to see it advertised for sale again on Autotrader a few weeks ago. By the next week it had gone.

The Forza had linked brakes as well. Not that it has any relevance.

Glad your happy with your Forza, I'm happy with the Wing. So all is well with the world.

Without actually figuring everything out like I intended but after discussing it with wise heads, I decided to try something.

I pumped up the left/rear lever and tied it back to the bar.
Using the vacuum bleeder, I sucked on the rear bleed nipple, topping up the reservoir as needed. Eventually, I got a decent glop of air.
Next, using the vacuum bleeder and without disturbing the lever, I switched to the front lower nipple. Again, I eventually struck air.
I repeated this (without touching the lever) and got some more air from the rear.

At this stage I was dying to try the feel of it and untied the lever and was very pleased. Job done.

I think, perhaps, the 'delay valve' may not like being disturbed during the bleed process and pumping the lever may help trap air in or around it.