ADVrider

Go Back   ADVrider > Bikes > Old's Cool > Airheads
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 04-19-2013, 12:18 PM   #31
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,164
Quote:
Originally Posted by AntonLargiader View Post
If you're going to get creative with an Arduino, why stay in the past by measuring vacuum? It's only a surrogate for smooth operation; these days we can measure the crank speed itself to figure out if it's running smoothly. That's what the Hexheads do.

Set a HES so that it reads the flywheel teeth, and then program the Arduino to compare alternate rotations. You will see the power pulse show up as crank acceleration, and you want the same acceleration on successive rotations.
I am not following you Anton. Do you mean like a K100 measures crank speed to run smoothly? You still need to use a manometer to set up both engines. The factory used a manometer to design the ports, intake, and exhaust.

I don't understand how intake pressure became a surrogate? Smooth? Crank speed is a surrogate of pressure as much as the other way around? Balancing an engine by crank speed would take numerous readings to calculate acceleration and deceleration within each revolution?
supershaft is offline   Reply With Quote
Old 04-19-2013, 12:41 PM   #32
Bill Harris
Confirmed Curmudgeon
 
Bill Harris's Avatar
 
Joined: Sep 2008
Location: backwoods Alabama
Oddometer: 6,308
Quote:
Originally Posted by More_Miles View Post
Just for the sake of completeness, here's the content of an email Mr. Cutter sent to the Airlist (to which I subscribe) on Feb 15, 2012.

http://www.advrider.com/forums/showp...5&postcount=28

Unless my Thunderbird-fu is greatly in error or I have a bunch of missing email from the archive (digital packrat!) that's the only thing I can find that Mr. Cutter had to say on the subject of the Harmonizer.
Well now, I am embarrassed. That is a completely reasonable and objective review. Guess I jumped the gun...

--Bill
__________________
'73 R60/5 Toaster
Luddite. Not just a philosophy, a way of life...
Bill Harris is offline   Reply With Quote
Old 04-19-2013, 12:58 PM   #33
Renner
combustophile
 
Renner's Avatar
 
Joined: Jul 2007
Location: sunny SoCal
Oddometer: 1,913
Quote:
Originally Posted by supershaft View Post
I am not following you Anton. ...
balancing power pulses rather than differential pressure upstream of the intake valve.
__________________
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
Renner is offline   Reply With Quote
Old 04-19-2013, 01:21 PM   #34
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,164
Quote:
Originally Posted by Renner View Post
balancing power pulses rather than differential pressure upstream of the intake valve.
That much I got but how?
supershaft is offline   Reply With Quote
Old 04-19-2013, 01:45 PM   #35
Renner
combustophile
 
Renner's Avatar
 
Joined: Jul 2007
Location: sunny SoCal
Oddometer: 1,913
Quote:
Originally Posted by AntonLargiader View Post
Set a HES so that it reads the flywheel teeth, and then program the Arduino to compare alternate rotations. ... you want the same acceleration on successive rotations.
what part is not clear?
__________________
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
Renner is offline   Reply With Quote
Old 04-19-2013, 01:56 PM   #36
Saltwater
Adventurer
 
Joined: Dec 2011
Location: Washington State
Oddometer: 17
New airhead owner response

I am only at about 250 miles past completion of refurbishment of a mini storage rescue R80, so not experienced in general, or never owned any other carb balancing product. I purchased it after reading the thread(s) on this forum. My unit works great, simple, and the electronic tach is mucho handy. Another great benefit is riding the bike with it hooked up. The case has a plastic hook on the top, which I attach to one of the control cables near the speedo/tach. My carbs are relatively balanced when accelerating, but way out of balance decelerating. Good to know, but not sure what to do about it.

Im a happy Harmonizer customer, and would definitely buy it again. Its idiot proof.
Saltwater is offline   Reply With Quote
Old 04-19-2013, 03:51 PM   #37
bgoodsoil
Dare to be Stupid
 
bgoodsoil's Avatar
 
Joined: Jul 2008
Location: Washington, DC, USA
Oddometer: 4,220
Quote:
Its idiot proof.
Sold!
__________________
'85 BMW r80G/S--Another G/S on the road--Central America on a Shoestring--Nova Scotia on a Shoestring--Never Leave a Man's Behind

Proud SmugMug User Support ADV: Don't give those cheap bums your discount code
bgoodsoil is offline   Reply With Quote
Old 04-19-2013, 05:39 PM   #38
AntonLargiader
Beastly Adventurer
 
AntonLargiader's Avatar
 
Joined: Aug 2003
Location: Charlottesville, VA
Oddometer: 4,126
Quote:
Originally Posted by Rob Farmer View Post
..so it would make sense to piggyback the existing hes in the bean can.
Might work, but it's not that much data. Just a pulse or two per rev, right? I want BIG data, like the Hexheads or ABS. 50 or 100 data points per rev.

Quote:
Originally Posted by supershaft View Post
I am not following you Anton. Do you mean like a K100 measures crank speed to run smoothly? You still need to use a manometer to set up both engines. The factory used a manometer to design the ports, intake, and exhaust.
No, that's still primitive with only a few points per rev. And sure the factory used various techniques to develop the airflow but how is that relevant? We're not redeveloping that.

Quote:
I don't understand how intake pressure became a surrogate? Smooth? Crank speed is a surrogate of pressure as much as the other way around? Balancing an engine by crank speed would take numerous readings to calculate acceleration and deceleration within each revolution?
If the crank turns smoothly it won't matter what the intake pressure is; the engine will feel smooth. And that's all we care about - read the above reviews. Smooth operation implies even operation. If you have drastically different pressure you will not get smooth crank motion. But I do think you can get even pressure without necessarily having the smoothest operation. I've seen it.

And yes, it will take numerous readings; that's the whole point of reading the flywheel teeth or maybe the cam sprocket teeth. Computers can deal with that kind of data no problem. The BMS unit on the Hexheads reads the gear teeth for the counterbalance shaft and basically treats each cylinder as a separate engine.

Imagine having the crank speed graphed in infinite detail, looking kind of like a sine wave. Each successive peak is from the opposite cylinder. You overlay odd peaks with even peaks to find the difference and then tweak operating parameters to make them the same. This is not rocket science; it's actually old news.

Intake manifold vacuum is VERY old news.
__________________
Anton Largiader largiader.com BMWRA.org
AntonLargiader is offline   Reply With Quote
Old 04-19-2013, 06:33 PM   #39
More_Miles
ber-n00b
 
More_Miles's Avatar
 
Joined: Aug 2009
Location: New Brunswick Canada
Oddometer: 312
Don't feed a geek beer and a good idea!

Quote:
Originally Posted by AntonLargiader View Post
And yes, it will take numerous readings; that's the whole point of reading the flywheel teeth or maybe the cam sprocket teeth. Computers can deal with that kind of data no problem. The BMS unit on the Hexheads reads the gear teeth for the counterbalance shaft and basically treats each cylinder as a separate engine.

Imagine having the crank speed graphed in infinite detail, looking kind of like a sine wave. Each successive peak is from the opposite cylinder. You overlay odd peaks with even peaks to find the difference and then tweak operating parameters to make them the same. This is not rocket science; it's actually old news.

Intake manifold vacuum is VERY old news.
Great! I've been wanting to play with a Rasberry Pi and Ardurino platform for a bit. This gives me a couple ideas!

Just curious, how does the BMS "read" the gear teeth? Embedded magnet and HES? Optically? With "frickin' lasers?" Some other secret squirrel method? I should look up ABS wheel rotation encoders... Similar idea I think.

Just thinking out loud here. If I understand what you're saying Anton, lets assume the following
  • A completely smooth engine, as if driven by an electric motor with zero pumping resistance would be a "carrier frequency" of F
  • The power pulses will impose an acceleration/deceleration around this carrier, and modulate the base carrier frequency
  • We can demodulate this signal (Frequency Modulation, or FM. Sounding very familiar!) to a data signal. Doesn't need to be audio but it could be. We only need to sample and analyse it.
  • If both cylinders are perfectly balanced, providing the exact same acceleration for each power stroke, then the demodulated signal would be a sine wave. The further away from balance, the less like a sine wave this signal will be.
Okay, what the hell. Re-read the above. Just shows that you shouldn't allow a techno-geek beer, computers and old motorcycles!
__________________
Larger than life and twice as ugly!
My photos: stewie.smugmug.com
More_Miles is offline   Reply With Quote
Old 04-19-2013, 07:03 PM   #40
supershaft
because I can
 
Joined: Sep 2010
Location: San Francisco Bay area
Oddometer: 8,164
Quote:
Originally Posted by AntonLargiader View Post
Might work, but it's not that much data. Just a pulse or two per rev, right? I want BIG data, like the Hexheads or ABS. 50 or 100 data points per rev.



No, that's still primitive with only a few points per rev. And sure the factory used various techniques to develop the airflow but how is that relevant? We're not redeveloping that.



If the crank turns smoothly it won't matter what the intake pressure is; the engine will feel smooth. And that's all we care about - read the above reviews. Smooth operation implies even operation. If you have drastically different pressure you will not get smooth crank motion. But I do think you can get even pressure without necessarily having the smoothest operation. I've seen it.

And yes, it will take numerous readings; that's the whole point of reading the flywheel teeth or maybe the cam sprocket teeth. Computers can deal with that kind of data no problem. The BMS unit on the Hexheads reads the gear teeth for the counterbalance shaft and basically treats each cylinder as a separate engine.

Imagine having the crank speed graphed in infinite detail, looking kind of like a sine wave. Each successive peak is from the opposite cylinder. You overlay odd peaks with even peaks to find the difference and then tweak operating parameters to make them the same. This is not rocket science; it's actually old news.

Intake manifold vacuum is VERY old news.
Oh, I see what you are getting at. What they are suppose to do and what they do are two different things. For instance, they have anti knock sensors. They don't ping. Yea, sure they don't.

I am sure all that sensor info helps the engine run better but the fact of the matter is that in order for a 1200 to run smoothly, you need to sync the TB's with a manometer. The entire intake and exhaust systems were designed with manometers and are tuned with manometers. I think that is relevant. Good luck telling a 1200 owner that manifold vacuum is old news when his TB's aren't synced properly. Good luck telling someone flowing 1200 heads for more power that manifold pressure is old fashioned. Let alone tuning said setup.

Yea, manifold vacuum is old news but it's still about the most important news.

Sure, I have occasionally seen an engine run smoother with different manifold pressures but it is almost always at or real close to idle and there is almost always a lot of other issues going on at the same time. No, manifold vacuum isn't perfect but it is still the best thing we have as far as bench flowing heads and syncing carbs and TB's. I disagree. Manifold vacuum isn't old fashioned or surrogate.

supershaft screwed with this post 04-19-2013 at 07:19 PM
supershaft is offline   Reply With Quote
Old 04-19-2013, 08:28 PM   #41
Plaka
Brevis illi vita est
 
Joined: Jun 2010
Oddometer: 4,573
Quote:
Originally Posted by Rob Farmer View Post
Good idea anton. The hall effect sensor goes low when the trigger passes so it would make sense to piggyback the existing hes in the bean can. Minor variations in throttle positions would upset the readings though, wouldn't you need to take the throttle position into account if messing crank speed?
I wouldn't use the beancan HES. It only gives 2 pulses per rev. Each of those pulses has some hysteresis so you are introducing a lot of variation. Read something like flywheel teeth and you get a massive train of pulses / rev so the variation is spread out. You still get noise but you get enough of it per rev to average and filter it, or ignore it.

The flywheel teeth are also easy to get to any number of ways, lots off opportunities to mount a precise mechanism.

But you still have to change the carb settings manually. So you are just making a shop tuning tool. Outside of the engineering exercise, it makes little sense over what is available already.

If you want to measure vacuum, an ordinary liquid manometer with damping is an ancient and accurate tool. Compensates for the weather nicely too.
Plaka is offline   Reply With Quote
Old 04-19-2013, 10:45 PM   #42
Rob Farmer
Beastly Adventurer
 
Rob Farmer's Avatar
 
Joined: Aug 2002
Location: Loughborough, Leicestershire. England
Oddometer: 5,040
Quote:
Originally Posted by Plaka View Post
If you want to measure vacuum, an ordinary liquid manometer with damping is an ancient and accurate tool. Compensates for the weather nicely too.
I agree completely and until I bought a harmonizer I've used a home made one for years. I've used just about every type of gauge over the years but have always preferred the conventional manometer. The harmonizer is the first bit of kit to replace my manometer, it's small enough to pack on a trip as well.

The arduino stuff is just fun, it's cheap, quick and easy to put something together that would previously have cost an arm and a leg to produce.

Rob Farmer screwed with this post 04-19-2013 at 10:50 PM
Rob Farmer is offline   Reply With Quote
Old 04-19-2013, 11:28 PM   #43
Plaka
Brevis illi vita est
 
Joined: Jun 2010
Oddometer: 4,573
Quote:
Originally Posted by More_Miles View Post
I like mine.

I've done a balance with a home made differential manometer since I bought the bike. Through ham-fistedness (is that a word?) I've managed to have the bike ingest transmission fluid a couple times. I was always happy with the results. Enter the Harmonizer.

When I hooked it up the first time, it was barely within spec according to the new tool (smily face lit up.) I managed to get it even closer to perfect balance. I adjusted the idle air screws for max vacuum, repeated, and rode. By the way, I'd never had a vacuum gauge to do this last adjustment before. I had done it old school, screw in to stumble, screw out to stumble, go half way between.

I always thought the BMW boxers were smooth. Well, after this, it was like riding a flying carpet. It was smoooooooth. Never been that smooth before. Easy starting, comes to an unassisted idle quicker, and just generally happy. I on the other hand may end up getting a "performance award" since my physical feedback (vibrations) have almost all gone away!
Will it run on 12VDC?
What does it cost?
How long does it last?
How sturdy is it?


I get that nice tune with something that cost less then $5, uses no electricity much less batteries, has an unlimited lifespan and is unbreakable.

I like my gizmos as much or more than the next guy. On this one, I figured out the simple approach not only delivers perfectly but it's the end of the road. Cannot be improved upon with compromising something...and I've given it considerable thought and I'm good enough to invent something better if it can be done. I've worked at breaking patents, I know the drill.

Plaka screwed with this post 04-19-2013 at 11:45 PM
Plaka is offline   Reply With Quote
Old 04-20-2013, 12:02 AM   #44
Plaka
Brevis illi vita est
 
Joined: Jun 2010
Oddometer: 4,573
Quote:
Originally Posted by Rob Farmer View Post
I agree completely and until I bought a harmonizer I've used a home made one for years. I've used just about every type of gauge over the years but have always preferred the conventional manometer. The harmonizer is the first bit of kit to replace my manometer, it's small enough to pack on a trip as well.

The arduino stuff is just fun, it's cheap, quick and easy to put something together that would previously have cost an arm and a leg to produce.
Does look like fun. The BASIC Stamp has been around almost 15 years and is still going strong. Lot of variations out there. I have two PLCs and development environments for my desktop which keeps me busy when I want to screw around with computers...I'd rather be riding in the summer.
Plaka is offline   Reply With Quote
Old 04-20-2013, 04:32 AM   #45
AntonLargiader
Beastly Adventurer
 
AntonLargiader's Avatar
 
Joined: Aug 2003
Location: Charlottesville, VA
Oddometer: 4,126
Quote:
Originally Posted by More_Miles View Post
Just curious, how does the BMS "read" the gear teeth?
I'll try to remember to look it up, but I think it's either an AC generator or what BMW calls a 2-wire HES. There's a short tooth that tells it where it is on the gear.

Quote:
[*]If both cylinders are perfectly balanced, providing the exact same acceleration for each power stroke, then the demodulated signal would be a sine wave. The further away from balance, the less like a sine wave this signal will be.
The way I see it, the demodulated wave form is whatever it is. It will be like a sine wave, but there's no reason to think it should be a perfect one. You should care about comparing demodulated L to demodulated R, not comparing either to a true sine wave. And it could be done graphically, to give the operator more information.

Otherwise, the demodulation stuff sounds about right.

I see this as something you could just hold up to the timing port. On the '81-on bikes you can see the flywheel teeth and the OT plate, so you can build a sensor plug that will 'see' them also. Hold it in the timing hole, tweak the carbs and you're done. No need to mess with the Bing screws or whatever port plugs that particular bike has.

It would have to work with pre-'81 bikes to be truly useful. I think that will be harder, but there's probably a way. Might have to paint the OT mark and get it optically.

Or, it could be that only reading the existing timing marks like OT/S/Z is enough. It's worth checking.
__________________
Anton Largiader largiader.com BMWRA.org
AntonLargiader is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 01:41 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014