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A vibrator helped me debug a motorcycle brake light system

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Re: A vibrator helped me debug a motorcycle brake light system

#51

I too have repurposed a similar machine to try to help me solve a nagging problem. One of my vehicles uses a hydraulic clutch. By design, air bubbles can be trapped in the master cylinder due to factory bends in the lines and the orientation of the master cylinder when it is properly installed. If this happens it will be impossible to shift the gears (manual transmission) until the air is bled from the lines. I tried…

pull a vacuum from the bleeder. problem solved.

ps, if you haven't annihilated your syncros, you can 100% shift without the clutch, just "burp the throttle" when you want to shift, meaning, let off the gas, change gears, back on the gas.

shifting up anyway.

downshifting is another story, as is starting from a stop, though I've had good luck with a disabled neutral safety switch and stopping in neutral, turning the car off, pop into 1st, start when the light turns. Hell on the starter and battery, but sometimes it's the only option.

Re: A vibrator helped me debug a motorcycle brake light system

#52

Earlier quoted context omitted.

For bleeding hydraulic brakes, which operate on a similar principle, the normal procedure is to open the bleeder valves on the slave cylinders and vigorously pump the pedal, refilling the master as necessary, until the fluid coming out of the bleeders is free of bubbles. Vibrating the lines won't do anything since the air bubbles fill their entire inside diameter.

I've been wrenching since my teens in the late 1970's and have learned a lot over that long time span. I was following, sometimes to the letter other times to the spirit, the documented procedure for burping this particular hydraulic clutch system. The system has bends from the factory that act to trap air and most aftermarket parts arrive pre-bled so that the installer doesn't need to deal with the issue because it…

you're putting pressure into a system filled with a fluid that does not compress, and air, which compresses a lot. The procedure for getting the air out of any system is pump the pedal, crack the bleeder, tighten, pump until you have pedal, repeat until no air comes out of the bleeder.

you can get fancy with a vacuum too but one person on the pedal pumping and one person on the bleeder, you'll get all the air out.

if you've been working on cars since the 70s, you'd know that what you're saying about "the usual pumping the clutch and cracking the bleeder valve process" being bad is nonsense. If you didn't bench bleed the master cylinder good enough, you're going to be bleeding things for awhile. Also, if you're dealing with abs, junction blocks, or bleeding wheels out of order you're going to be there awhile.

clutch systems are a single line going from a mc to a hydraulic fork actuator. They take a whole 10 minutes to bleed starting from bone dry and you don't need to tap the air out, that what bleeding them is doing

Re: A vibrator helped me debug a motorcycle brake light system

#53
This reminds me of a project I built in a class during my EE degree--I wanted a thing that would pick out the beat in a song and flash an LED accordingly. I thought it would be pretty easy to just look for spikes, but you can't have a constant threshold or else you will just run the LED for the entire duration of some high-energy portion of the song (or else you will hardly ever run it at all). It needed to be adaptive, but the adaptive threshold needed to be able to respond quickly to changes in the "average energy" of a song. It took quite a lot of calibrating to make it work properly, and I learned a lot in the process.

Re: A vibrator helped me debug a motorcycle brake light system

#54
post #31

On a bike you have the front brake lever at the throttle on the right hand. You always, always have to have at least two fingers on the brake lever and control the throttle with the thumb and palm. It is completely irresponsible to ride not doing that because sudden obstacle will not give you enough time to put them back on it. Then you lose 60-80% of braking power for a second or two. If you are doing it right then…

I know a few bikers do something similar as you describe. I want to point out it is not generally accepted truth, e.g. the German ADAC explixitly teaches to keep fingers off the brake until needed. The idea being that if you're surprised by something, you're much more likely to slam the brake, introducing instability or locking up the front. You don't hover over the brake in a car either.

The local state motorcycle training course will not allow you to cover the brake while learning. They consider it especially dangerous for new riders for the reason you stated.

Re: A vibrator helped me debug a motorcycle brake light system

#55

> Motorway is an hour out from where I live. Each tweak meant hopping on the bike and carving out hours to test. It's easier said than done, but you might want to approach this like a data science project. Record the data from your test runs, annotate the behaviour you want, and build up a dataset. You should be able to experiment with any number of tweaks (admittedly except for the data sampling itself) without havi…

Yeah, I'm very surprised they didn't record the data from a single ride, with some sort of manual entry for "brakes should light up now", and then test at home.

Re: A vibrator helped me debug a motorcycle brake light system

#56

Earlier quoted context omitted.

I've been wrenching since my teens in the late 1970's and have learned a lot over that long time span. I was following, sometimes to the letter other times to the spirit, the documented procedure for burping this particular hydraulic clutch system. The system has bends from the factory that act to trap air and most aftermarket parts arrive pre-bled so that the installer doesn't need to deal with the issue because it…

you're putting pressure into a system filled with a fluid that does not compress, and air, which compresses a lot. The procedure for getting the air out of any system is pump the pedal, crack the bleeder, tighten, pump until you have pedal, repeat until no air comes out of the bleeder. you can get fancy with a vacuum too but one person on the pedal pumping and one person on the bleeder, you'll get all the air out. if…

I follow all the recommended bleeding procedures for the assembly and since I did not want to remove the assembly from the vehicle to enable burping it, I improvised with the back massager, hoping to speed the process.

>you're putting pressure into a system filled with a fluid that does not compress, and air, which compresses a lot. The procedure for getting the air out of any system is pump the pedal, crack the bleeder, tighten, pump until you have pedal, repeat until no air comes out of the bleeder.

I agree that this is SOP for bleeding hydraulic systems. Been there, done that.

>you can get fancy with a vacuum too but one person on the pedal pumping and one person on the bleeder, you'll get all the air out.

In normal practice this also works. Many times though I am a one man band and I'm not bendy enough any more to be able to keep the pedal depressed with one leg while I contort and stretch over to the bleeder so I have resorted to using a section of PVC cut to length so that it can be jammed into the front of the seat base after rapidly pumping the pedal - holding the pedal at the floor, thus freeing the rest of my body to navigate to the bleeder.

>if you've been working on cars since the 70s, you'd know that what you're saying about "the usual pumping the clutch and cracking the bleeder valve process" being bad is nonsense. If you didn't bench bleed the master cylinder good enough, you're going to be bleeding things for awhile. Also, if you're dealing with abs, junction blocks, or bleeding wheels out of order you're going to be there awhile.

Like I said I have been turning wrenches since the late 1970's. Insinuating that I don't understand the process or problem well enough sounds powerful and righteous on your end but comes off as an unnecessary personal attack on my end. I've maintained foreign and domestically produced automobiles manufactured during the period from 1934-2022 including teaching myself troubleshooting of electronics and sensor-driven vehicles; heavy equipment on drilling rigs including mud pumps, air and hydraulic compressors, shakers, sniffers, MWD tools, LWD tools, downhole logging tools including electronics; backhoes, bulldozers, maintainers, dump trucks, water hauling trucks including air brake systems, jackhammers and compressors; small gasoline and diesel engines on yard tools and heliportable drilling rigs; rebuilt gasoline and diesel engines from a short block to an operating engine as a night mechanic for a seismic crew. I haven't done everything and I have no official certs but I have more diverse experience than most techs will get because I never walked away from an opportunity to tear something down to see how it worked. I'm pretty sure I understand the situation with this master cylinder system and like I mentioned, I followed the manufacturer recommended procedure for bench bleeding and when that didn't work I improvised. It didn't work because there was a bad o-ring in the master cylinder check valve that allowed air into the system whether it was on the bench or in the vehicle.

>clutch systems are a single line going from a mc to a hydraulic fork actuator. They take a whole 10 minutes to bleed starting from bone dry and you don't need to tap the air out, that what bleeding them is doing

I do not disagree with anything that you have said here but will leave this bench bleeding video [0] link for your own amusement. The fun starts at 4:31 in the video link. In my process, I substituted a back massager with a length of PVC pipe for the screwdriver since the master cylinder assembly was still installed in the vehicle. Prior to this, I bent or twisted the components so that it would be easier for air to flow up and out past anything that would normally be a trap.

[0] Perfection Clutch Bench Bleeding a Clutch Master Cylinder - https://youtu.be/91IYY_YENRw?t=271

Re: A vibrator helped me debug a motorcycle brake light system

#57

I too have repurposed a similar machine to try to help me solve a nagging problem. One of my vehicles uses a hydraulic clutch. By design, air bubbles can be trapped in the master cylinder due to factory bends in the lines and the orientation of the master cylinder when it is properly installed. If this happens it will be impossible to shift the gears (manual transmission) until the air is bled from the lines. I tried…

pull a vacuum from the bleeder. problem solved. ps, if you haven't annihilated your syncros, you can 100% shift without the clutch, just "burp the throttle" when you want to shift, meaning, let off the gas, change gears, back on the gas. shifting up anyway. downshifting is another story, as is starting from a stop, though I've had good luck with a disabled neutral safety switch and stopping in neutral, turning the ca…

Thanks for this additional reply. Pulling a vacuum from the bleeder screw may be problematic since air can be pulled past the bleeder screws and you might not ever achieve a vacuum there unless you can install an open port in place of the bleeder screw and attach your MityVac or other tool to that port. I pulled vacuum at the reservoir end as was recommended in several forums and videos. It did pull air up to the reservoir but without straightening all the kinks in the system that act as traps it could not evacuate all the air. I spent multiple hours at 25 psi and never successfully bled the system. In theory it should work great though.

I'm a longtime manual transmission driving speed-shifter with broad experience push-starting or roll-starting vehicles with dead batteries or other problems. I have even had one automatic transmission vehicle that could be started by putting the transmission into forward or reverse gear and turning the key so that the starter bendix drive pinion gear would engage and rotate the flywheel until it cranked the engine. Gasoline engine - 283 cubic inch Chevrolet with a PowerGlide transmission behind it. This was in a 1946 Chevy PU that had no top speed that I ever found. It would go faster until your own common sense took over.

Downshifting and upshifting by RPM are useful skills for anyone driving a vehicle with a manual transmission. Catching the point where your RPMs allow you to slip into a lower gear takes a little practice. You should do like I did and refine your skills in an old Ford dump truck with dicey hydraulic brakes, one headlight bulb, no windshield wipers, and a 6 cubic yard load of crushed limestone in the dump bed. It's more fun that way.

Re: A vibrator helped me debug a motorcycle brake light system

#58

I too have repurposed a similar machine to try to help me solve a nagging problem. One of my vehicles uses a hydraulic clutch. By design, air bubbles can be trapped in the master cylinder due to factory bends in the lines and the orientation of the master cylinder when it is properly installed. If this happens it will be impossible to shift the gears (manual transmission) until the air is bled from the lines. I tried…

Your issue with the o-ring reminds me of the time my buddy and I tried replacing the flex-line to one of his rear brake calipers. We rented one of the vacuum bleeder pumps from Auto-Zone, replaced the flex line, slightly loosened the bleeder cap and went to town. Sucked a ton of air out as the new line filled, but then there was a constant stream of tiny bubbles. He wanted to make absolutely sure that the line was cl…

I'm glad that something in the post helped you remember something useful. You are spot-on with your description of the situation.

Good luck to you.

Re: A vibrator helped me debug a motorcycle brake light system

#59

I too have repurposed a similar machine to try to help me solve a nagging problem. One of my vehicles uses a hydraulic clutch. By design, air bubbles can be trapped in the master cylinder due to factory bends in the lines and the orientation of the master cylinder when it is properly installed. If this happens it will be impossible to shift the gears (manual transmission) until the air is bled from the lines. I tried…

Your issue with the o-ring reminds me of the time my buddy and I tried replacing the flex-line to one of his rear brake calipers. We rented one of the vacuum bleeder pumps from Auto-Zone, replaced the flex line, slightly loosened the bleeder cap and went to town. Sucked a ton of air out as the new line filled, but then there was a constant stream of tiny bubbles. He wanted to make absolutely sure that the line was cl…

Something I've done to help with this is wrap the bleeder threads with PTFE tape. It will make a one time seal on the non-taper threads, but it's enough for a flush

Re: A vibrator helped me debug a motorcycle brake light system

#60

Earlier quoted context omitted.

I know a few bikers do something similar as you describe. I want to point out it is not generally accepted truth, e.g. the German ADAC explixitly teaches to keep fingers off the brake until needed. The idea being that if you're surprised by something, you're much more likely to slam the brake, introducing instability or locking up the front. You don't hover over the brake in a car either.

The local state motorcycle training course will not allow you to cover the brake while learning. They consider it especially dangerous for new riders for the reason you stated.

This looks counterproductive. I can get that when one first learns to ride and therefore has no idea of what to expect from the road and from the bike this sort of precaution might have some sense. For about first couple hundred of kilometers/miles. But no more than that.

The whole point of learning to ride is to train yourself to always be prepared and situationally aware, to maintain total awareness of what you are doing, what is going on ahead and behind you, and keeping being able to correctly react as fast as possible whatever happens. Thus fingers on the brake.

They are seriously out there to kill you. Be it distracted car drivers, sloppy road maintenance, stray dogs, bad weather, random idiots.. any of this will kill you if you relax.

An occassional lowside or two in one's first two seasons most likely won't. Given even a mediocre protection set, one will get away with a bit of shock and maybe needing a new pair of pants. And a whole lot of training of the kind no school can give. Like when to pull the front brake and when to just open throttle and hope for the best.

Besides there is a saying - if you do not crash once a season, you do not ride, period.

Which is a grim reminder of that if one does not push oneself, one is losing skill.

I ride for about 30 years already and this is true. Motorcycles are not safe and cannot be safe, safety isn't in the concept, and this is what we love about them.

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