My First Commando...

I had ordered MadAss' 1/2" MC resleeve kit which comes with stainless braided hose and a coupler fitting for the fork bulkhead mount point to hard line female end.
I noted a hose routing issue from the MC b/c of the new "UK" Roadster handlebars...there is not much clearance...unless I rotate the MC upwards so the stop switch fitting hex section clears the bar...then the brake level is a rotated up a bit higher than I'd like.
Gotta love motobikes...change one thing and spend ages working out all the knock on effects....

Gotta love motobikes...change one thing and spend ages working out all the knock on effects....>

Ya just rationalizing like we all do to ease reality of Mark Twain stating humor is based on ongoing tragedy. We hate our failures but others examples and our hope of similar satisfaction before we die drives us on. If not satisfied with just good enough then there's no end to Norton upgrades compromises work arounds.

Take heart it only took hobot about a decade to feel competent then about another decade to actually be competent on stupid simple Commando.

"Any tips for rear fitting, like order of spacers/washers on the hub axle bolt and those cush rubbers?"

Make a fake axle spacer similar to the long one on the right 060324 , but narrower by about 1/4". Steel, wood, alloy, whatever, same or slightly larger ID.
Alternately, be prepared to lever the SA apart.

Before you're ready to mount, find a pc of wood or ply or similar positioned under the bike, so that you can roll the wheel up on it from the rear and it will keep the wheel at the right height to fit the axle with the bike on the center stand. Mine is about 1.25" thick. Cush drive rubbers must obviously be placed (correctly) in the wheel hub first, and be tight enough to not wiggle out while you're fiddling . I assume you have the stock axle, and the stub (dummy) axle is already fitted to the SA on the left with the brake drum and chain in place.
Run the axle adjusters forward and out of the way.
Have the washer, axle, RH spacer, speedo drive with top hat, close to hand on the right. Be sure yr brake hub is positioned with the plate stop in its slot on the left side of the swingarm.
Roll the wheel toward its position near the brake hub at an angle from the right rear, squeezing past the fender and up onto the block on the floor or stand. Rotate the wheel in place until the brake drum pegs will enter between the cush rubbers in all 3 places, then push the whole wheel leftward onto the pegs as far as you can by hand.
Put the speedo drive up to the wheel's lockring and rotate until you feel the drive tangs fall into the slots in the lockring, then squeeze the fake spacer between the top hat and the SA, fit the washer and axle, and tighten to squash it all together. Remove the axle and the fake spacer and you shd now have JUST enough room to mount the real spacer and fit the axle again. Don't tighten yet.
Go to the left side and ensure everything's in place. See that your rear sprocket is well aligned so the chain runs straight back from the front sprocket. Before the final torque-up on the LH dummy axle: back off the brake adjuster several turns and stand on the brake pedal to center the shoes in the drum, reach down and tighten the dummy axle (15/16) while the brake is still applied. Let off the brake and the wheel shd spin freely.

Go back to the right side and torque the axle after ensuring that the rear wheel lines up with the front wheel (an entire project in itself). Bring the axle adjusters back to touch the axle(s) and lock them down. Do NOT rely on the slots to tell you if the wheel is aligned. Fit the speedo cable to the drive.

Go back to the left side and run the brake adjuster nut up while spinning the rear wheel. Take the headphones off, turn down the music, and you shd be able to hear as soon as you've gone too far with the nut. Don't be tempted to run with a shoe "just" touching, wd get hot in a hurry, and not necessary.

Check drive chain tension and use axle adjusters to correct if necessary, moving adjusters an equal amount both sides to not lose alignment.

Thanks Mr.R...very helpful, at least after I suss'd what SA was ;-)

Trying to bleed FB...not getting fluid to progress out bleed screw along clear hose to one man type bleeder bottle. Fluid just sucks right back into screw upon release of lever. Leaving it O/N with lever pulled in to see if it self bleeds. Have not had this issue bleeding cars or my Bonneville...but that was not from a dry system, just fluid change.
Suggestions?

Tornado said:

Thanks Mr.R...very helpful, at least after I suss'd what SA was ;-)

Trying to bleed FB...not getting fluid to progress out bleed screw along clear hose to one man type bleeder bottle. Fluid just sucks right back into screw upon release of lever. Leaving it O/N with lever pulled in to see if it self bleeds. Have not had this issue bleeding cars or my Bonneville...but that was not from a dry system, just fluid change.
Suggestions?

Click to expand...

I think you're supposed to close the bleed nipple each time before releasing the lever. So open to pump it, and then close to stop fluid returning when brake lever is released.

Yes I did that for quite a while...not easy to reach both at once (must be impossible with the old HiRider bars). Could not make fluid progress along tube.

I can think of only 4 ways for that to happen. There are probably others?

Something is inside the line somewhere, blocking the new fluid from reaching the bleeder, and you're just squeezing bubbles.
Your bleeder screw is faulty and does not seal off when tightened.
Your caliper is damaged at the seat where the bleeder nipple sits and will not close off.
Your MC is empty or too low on fluid and you're pumping air down the line.

New lines, all ran freely with cleaner sprayed thru. Caliper also had passages sprayed thru, ran free. Bleed screw is original but seems to seal as when lever pumps, no fluid moving but when bleeder is open a 1/2 turn fluid moves down tubing a little, back other way if I release lever. Trying to pump MC, then crack bleeder open sort gives a small fluid flow, but stops and repeating process doesn't seem to make any fluid progress. It's as if MC cannot give any real pressure...reservoir has not seemed to deplete any amount what so ever after a couple of hours of this.
Also note, when I took it off bike weeks ago, had to hook up caliper and bleed in fluid to operate pistons to unseize them...that all worked fine...bleed only took a few minutes on the bench. This is now the 1/2" resleeved MC...new MC piston with cups/seals etc.

Overnight gravity bleed made no diff. Took everything off bike, setup on bench to better assess things. After trying many different things, found applying suction to bleeder via syringe was the only way to make fluid move and for first time started seeing reservoir level drop. Ran 10-20 reservoirs worth of fluid through...little to no bubbles coming out. Tightened up bleeder, tested lever pulls while monitoring caliper pistons....very slight 1-2mm of piston advancement with a full lever pull...and this small amount fully retreated each time lever released.
The Resleeve kit came with several MC piston shim caps of various thickness and a brief note about potentially being needed for differences in MC's used in various years...but no actual explanation of how to assess when needed. So, I will now try the shims, smallest first to see if things change. Basically, these will cause the piston to start from further down the MC bore and end up further down/bottomed out than with no shim installed.

Following with interest, as I have the same kit, yet to be mounted.
Did you perhaps install the caliper pistons dry? If so, the seals may have partially "rolled" and now prevent any piston movement.
I'd pull those pistons out, lube with fluid, and make sure they are traveling freely in and out of the caliper bores.

And here are a couple of helpful things that L.A.B. showed me some time ago-
http://www.slideshare.net/shaikusmanshag/5-classification-of-brakes

Put fluid on pistons and seals prior to inserting in caliper. Getting pistons pushed in was somewhat challenging...had to thump them down with wooden end of hammer. Don't think those seals are rolled as I'm not feeling firm pressure at MC lever...every pull is easy, fully reached end travel...if caliper pistons jammed, pressure should be maxed out and/or fluid leaking there.
It is possible the MC piston seals got inverted during insertion, these were also wetted out with fluid beforehand but still something to check.

The slides you linked were revealing..." upon release of brake pedal, piston pushes back by force from the spring, a vacuum forms in the cylinder as piston returns, causing primary seal to collapse allowing fluid to flow into cylinder to relieve vacuum." I don't think that is happening in my situation...the vacuum remains until all the pushed out fluid has slowly returned the way it left the MC...so no net progression of caliper pistons.
Why this happens is either the shimming is needed or MC seals not correctly seated/are inverted.

With the cap off the upright master cylinder, you shd be able to see the returning fluid spurting upward through the bypass port, noticeably disturbing the surface of the fluid in the reservoir.
Does your MC piston spring return the lever quickly? Is there friction at the lever pivot that wd resist the spring action?
Pics of the madass piston w seals the right way, flared end of seals pointed "downstream":

Tornado said:

Bleed screw is original but seems to seal as when lever pumps, no fluid moving but when bleeder is open a 1/2 turn fluid moves down tubing a little, back other way if I release lever.

Click to expand...

You should be closing the bleed nipple before you release the lever each time.

Tornado said:

Trying to pump MC, then crack bleeder open sort gives a small fluid flow, but stops and repeating process doesn't seem to make any fluid progress. It's as if MC cannot give any real pressure

Click to expand...

With one hand on the brake lever, the other opening and closing the bleed nipple;

1.Open the bleed nipple
2.Pull the lever
3.Close nipple
4.Release lever.

Then repeat quickly at a rate of 15-20 times per minute.

Tornado said:

It's as if MC cannot give any real pressure

Click to expand...

As long as there is a considerable amount of air in the system then you won't feel any 'lever' pressure.

Tornado said:

" upon release of brake pedal, piston pushes back by force from the spring, a vacuum forms in the cylinder as piston returns, causing primary seal to collapse allowing fluid to flow into cylinder to relieve vacuum." I don't think that is happening in my situation...

Click to expand...

Unlike fluid, air tends to act like a spring, compressing and expanding along with M/C piston movement so there's often not enough vacuum generated when the piston retracts to draw fluid into the system in any quantity.

To test/bleed the master cylinder, (covering any paintwork with rag etc.) with fluid in the reservoir disconnect the hose, place your finger over the M/C outlet so it's airtight then operate the lever several times.
You should feel air at first, then fluid squeezing past your finger with some force as you operate the lever.

The last test fails...pulling lever with finger over MC outlet port...no pressure...just a dribble comes out, not past my gloved finger, lever at full throw.
I withdrew the piston fully, checked the seals, all seems fine, not inverted etc. When reinserting piston, held finger on port and suddenly had decent pressure just as piston last seal began entering bore...continuing in made finger seal blow off. But when lever installed, it holds piston too far into bore, such that secondary seal is already past the first larger hole in reservoir. Removing lever let's spring push piston seal back past hole and pressure can build.
Looks like that's the issue...

Madass agrees, reached same conclusion just before I posted last tests to him. Thinks this came up before on these forums...solution was to file the piston/lever contact area to slightly shorten distance to seal.

As seen in the diagram above the "rest position" (lever installed and released) of the primary cup shd be just inboard (toward the lever) of the bypass port. If you want to clean it all up to test with your mouth: plug the brake switch hole with a switch or with a bolt and blow into the outlet. Air shd move through the tiny port into the reservoir, but the port shd close off almost immediately as you pull the lever so that air won't pass. If the primary cup is too far in, you can't bleed the system 'cause it's always "closed" and if it's too much farther out, you're wasting lever travel.
I just measured the distance from the throat of the MC to the outside end of the madass piston and got .282" with an RGM lever and .288" with a stock lever. These numbers are not all that reliable, since the MC is cast and the throat is not machined flat, but it might give you a baseline?
Your reservoir cap is vented with a tiny hole that's not plugged, right?

OK, I ground down the lever pawl...had to take off quite a large amount, maybe 1/4"!!
Now the seal can be seen just inside the reservoir first hole with no force on lever, and there is slight gap at contact point...level can rattle a bit against piston end.With the small amount of fluid I had left on hand, I got some pressure out the port and felt descent back pressure on lever.
Off to buy more fluid and do a complete test. Guess I can always source replacement lever should I have messed it up, gone to far.

When inserting MC piston, I can see primary seal pass fist hole, then when piston fully in bore with no spring compression, secondary is not yet gone past first hole. With unmodded lever, secondary was well past first hole..that is not correct as per diagram and not allowing new fluid into space between sec/pri seals. Only second smaller hole can flow fliud.
Now with moded lever, secondary seal sits just before first hole with no lever pressure...fluid can enter thru that hole into sec/pri space until lever pulls second seal past hole...nearly immediately after moving.

1/4" sounds like a lot. Replacement shd not be a problem if too much filed away. I have an extra if you're stuck.
Might wanna polish those contact surfaces carefully and watch the lever pad (boot removed) move across the face of the piston end as it travels during operation. Last thing you need is for the lever pad to fall off the piston face...