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 11-04-2012, 05:58 PM   #76
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Quote:
Originally Posted by disston View Post
It sounds like you were lucky to have the left side on compression when you set the valves. But I'm not one to smack a gift horse in the mouth.

Here's where i stand.

buttoned everything up. Want to note, when i did do the rubber pieces between the carbs and cylinders i took the carbs off and gave them a basic clean.

Followed this how to to a T. Was for newer bings, but similarities were there. http://www.ukgser.com/forums/showthread.php?t=231158

I used CRC carb cleaner.

Once cleaned, blew the carbs out with Air. made sure everything was dry. reinstalled. I tightened everything i removed, Main Jet assembly, pilot jet, and mixture screw. then backed off the mixture screw 2.5 Half turns, thats where it was pre removal.

Reinstalled the carbs, positioned the throttle cables to the point where the cable was not activating the throttle body.

I then fired up the bike.

Sounded better than before. Could still hear the valves tapping, but not as loud as before. Not loud enough to worry me. Started off at a low idle 500 or so rpms, i started messing with the mixture screw to where it sounded good to me.

That brought RPM's up to about 1500. Seems too high. After idling here for about 15 minutes, RPM's came back down to about 500 with clutch out, clutch in 1500. But within 5 seconds of having the clutch out it would start back firing before cutting out.

Figured i'd just ask whats going on, here on the forums before proceeding. Perhaps something to do with the throttle screw? or something i did within the carb?


Thanks for everyones help though, i'm learning. thats for sure...
Yachtie is offline   Reply With Quote
Old 11-05-2012, 10:05 AM   #77
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,372
Your bike does not do what I think it should be doing. You say the idle is high when cold and then drops to 500 when warmed up? Are you using the Chokes? Sometimes called Enrichners. Your bike has a lever attached to the left side of the Airbox with cables that go to the carbs. This is the control for the Enrichners. It is to be used when starting a cold bike. Are you using the Enrichner when the bike is cold, it idles high, and then turning it down later when the bike is warm and the idle is now 500 rpm.

An idle when warm of 500 rpm is a little low.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 11-05-2012, 11:00 AM   #78
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Quote:
Originally Posted by disston View Post
Your bike does not do what I think it should be doing. You say the idle is high when cold and then drops to 500 when warmed up? Are you using the Chokes? Sometimes called Enrichners. Your bike has a lever attached to the left side of the Airbox with cables that go to the carbs. This is the control for the Enrichners. It is to be used when starting a cold bike. Are you using the Enrichner when the bike is cold, it idles high, and then turning it down later when the bike is warm and the idle is now 500 rpm.

An idle when warm of 500 rpm is a little low.

Negative, bike did the opposite.

Started idling at 500, then went up to 1500-1800. But after 20 minutes or so at idle. It began dropping rpm and stalling out. For instance, it would die, so i start it back up keep the clutch in and RPM is about 1500-1800. Let clutch go and RPMs drop to 500 and then stalls out. Bike is in neutral, before anyone asks.
Yachtie is offline   Reply With Quote
Old 11-05-2012, 11:39 AM   #79
headtube
6 months of winter!
 
headtube's Avatar
 
Joined: Sep 2012
Location: Toronto
Oddometer: 217
Quote:
Originally Posted by Yachtie View Post
then backed off the mixture screw 2.5 Half turns, thats where it was pre removal.
Set your idle mix screw (1) turn out. 2.5 is too much. Start at one turn, then make "small" adjustments from this point to even out your idle sync.

Note: don't confuse the throttle stop screw with the mixture screw. Although both screws produce an idle of sorts. A good rule of thumb when setting the throttle stop screw is to screw this in until it touches the arm, (this arm is attached to your throttle cable/s) then turn it in one full turn. Adjust each side the same and set your idle from there making small adjustments.
headtube is online now   Reply With Quote
Old 11-05-2012, 12:26 PM   #80
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,372
Headtube is right. All different models of Bings on many different models of BMW bikes, they all have a specific setting for the idle mix screw. This is the smaller screw on the bottom of the carbs. On your model this screw is set to One (1) full turn out. Please set this screw to ONE full turn out and leave it there.

The idle speed screws are the larger screws on the bottom side of the carbs. They can also be set to one turn in at this point. these are the screws you will use to balance the carbs and get the correct idle speed.

Use the enrichners to start the bike. Turn them part way off after bike starts. If cold out the need to be a little bit on for a little longer but if warm out or the bike is already warm they can be taken completely off sooner.

You are not supposed to idle an Airhead in a stationary place for 20 mins. If you really need to do this set up a large box fan to blow air on the bike. You are allowed to idle for only 5 mins. The fact your bike dies after 20 mins of idling is probably because it is over heated.

Once you get the bike running good enough to ride you should take it for a ten to twenty min ride to warm further. At this point you are ready to balance the carbs. Do you have the shorting tools, little studs to fit on plugs, or other balancing tool? Idle speed should not be higher than 1000 rpm in my opinion. I hear of someriders having their bikes running at 1100. Still 1500 is too high.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 11-05-2012, 02:19 PM   #81
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Just to be clear I took a few pics.

I believe this is te smaller screw you speak of and this is set to one full turn out




This I take it is the larger screw? Idle speed screw? One turn out? If its not and I'm missing a screw, what should this one be set too cause I already fiddled with it.






Quote:
Originally Posted by disston View Post
Headtube is right. All different models of Bings on many different models of BMW bikes, they all have a specific setting for the idle mix screw. This is the smaller screw on the bottom of the carbs. On your model this screw is set to One (1) full turn out. Please set this screw to ONE full turn out and leave it there.

The idle speed screws are the larger screws on the bottom side of the carbs. They can also be set to one turn in at this point. these are the screws you will use to balance the carbs and get the correct idle speed.

Use the enrichners to start the bike. Turn them part way off after bike starts. If cold out the need to be a little bit on for a little longer but if warm out or the bike is already warm they can be taken completely off sooner.

You are not supposed to idle an Airhead in a stationary place for 20 mins. If you really need to do this set up a large box fan to blow air on the bike. You are allowed to idle for only 5 mins. The fact your bike dies after 20 mins of idling is probably because it is over heated.

Once you get the bike running good enough to ride you should take it for a ten to twenty min ride to warm further. At this point you are ready to balance the carbs. Do you have the shorting tools, little studs to fit on plugs, or other balancing tool? Idle speed should not be higher than 1000 rpm in my opinion. I hear of someriders having their bikes running at 1100. Still 1500 is too high.
Yachtie is offline   Reply With Quote
Old 11-05-2012, 03:13 PM   #82
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,372
Close but no cigar. You named them correctly. The short version, Idle Mix Screw (the little one) is one turn Out, Idle Speed Screw (the big one) is one turn In.

A longer version. The idle mix screw is regulating the amount of gas the idle circuit carries. The more out the screw is the richer the mixture will be at idle. For an R90/6 the official starting place for the little idle mixture screw is one turn out. You may adjust this some but don't do that at first till you get the speed closer to what it needs to be. Set the idle mix at one turn out. This is the adjustment in the Bing manual for all R90/6es.

The idle speed screw provides a stop for the butterfly so it doesn't close all the way. It holds the butterfly open a very tiny amount. The two carbs are balanced with the idle speed screws. They need to be even in the sense that the two cylinders are running at the same speed and pulling the same amount. That is why it is called "balanced". Set the idle speed screws in one turn from the moment they first contact the bell crank of the throttle shaft. This is hard to do when the carbs are on the bike, the screw and the part it contacts are on the back side of the carb, so it's just hard to do. You want to try and set the speed screws to ONE TURN IN.

The Mix Screws ONE TURN OUT.

You need a method of balancing the carbs to get these settings even between the two sides. I'll ask again, Do you have the shorting rods or a manometer or other tool that compares carb vacuum so you can balance the carbs?
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 11-05-2012, 03:28 PM   #83
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Thanks for the clarification and no. I do not have those tools at the moment.

Quote:
Originally Posted by disston View Post
Close but no cigar. You named them correctly. The short version, Idle Mix Screw (the little one) is one turn Out, Idle Speed Screw (the big one) is one turn In.

A longer version. The idle mix screw is regulating the amount of gas the idle circuit carries. The more out the screw is the richer the mixture will be at idle. For an R90/6 the official starting place for the little idle mixture screw is one turn out. You may adjust this some but don't do that at first till you get the speed closer to what it needs to be. Set the idle mix at one turn out. This is the adjustment in the Bing manual for all R90/6es.

The idle speed screw provides a stop for the butterfly so it doesn't close all the way. It holds the butterfly open a very tiny amount. The two carbs are balanced with the idle speed screws. They need to be even in the sense that the two cylinders are running at the same speed and pulling the same amount. That is why it is called "balanced". Set the idle speed screws in one turn from the moment they first contact the bell crank of the throttle shaft. This is hard to do when the carbs are on the bike, the screw and the part it contacts are on the back side of the carb, so it's just hard to do. You want to try and set the speed screws to ONE TURN IN.

The Mix Screws ONE TURN OUT.

You need a method of balancing the carbs to get these settings even between the two sides. I'll ask again, Do you have the shorting rods or a manometer or other tool that compares carb vacuum so you can balance the carbs?
Yachtie is offline   Reply With Quote
Old 11-05-2012, 03:38 PM   #84
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Also, where should this throttle cable "tensioner" screw be set roughly

Yachtie is offline   Reply With Quote
Old 11-05-2012, 03:41 PM   #85
Airhead Wrangler
Adios Mexico
 
Airhead Wrangler's Avatar
 
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,338
Quote:
Originally Posted by Yachtie View Post
Also, where should this throttle cable "tensioner" screw be set roughly
Such that it has enough free play that it allows your idle adjuster screw to dictate idle speed and not cable tension. You also need to set each side so that your throttle "picks up" both throttle shafts off the idle speed stop exactly in unison. First idle speeds need to be synced with vacuum gauges or shorting sticks, etc. The next thing that needs to be synced is when the throttle picks up both butterfly shafts off the idle stops. That's done with those cable adjusters.
__________________
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
Airhead Wrangler is offline   Reply With Quote
Old 11-05-2012, 04:19 PM   #86
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,372
Balancing the carbs is a very important part of making the bike run as it should and smoothly. Unbalanced the bike will get poor gas mileage, be hard to start, be ruff and vibrate and even make unnatural noises. This is the key to making an Airhead run. It is some what an Art, maybe more Art than science. That can't really be true because these are machines but it's a fact that some tuners are better at it than others and it's hard to say why.

This is one method of balancing carbs. It involves shorting out the spark plug leads so the bike tries to run or does run on one side. You need this tool. You can buy it or you can make it yourself;



Sorry the picture is so small. These are for sale at Northwoods Airheads;

http://imageshack.us/a/img849/6267/t...img1229133.jpg

To make a pair of these tools use a long 4mm screw from the neighborhood hardware store. The screw is 4 x .7 and should be 60 or 70 mm long. The nipples that came with a new pair of spark plugs go on one end and you will also need a 4 x .7 nut to lock the nipple on the end. Leave enough thread of the nipple open on the end so the rod can be attached to a spark plug. The head of the screw is cut off so the plug wire can be attached to it. Tighten it down a little with a wrench, it will vibrate loose if not tightened. It is important that the plug wires do not become unconnected when the bike is running. They should be firing the plugs or be shorted to ground to not fire the plugs but they should not be just unconnected, that can cause ignition problems.

Once the bike is warm and the studs are connected with the bike at idle you short out one plug with a screw driver so the bike will run momentarily on one cylinder. Note the sound and speed of the bike on one cylinder. Take the screwdriver away and rev the throttle a little to clear pooled gas in the intake and then short out the plug on the other side. Note the sound and the speed of the bike on the other cylinder. If one cylinder is running faster than the other adjust the speed screws a little, either one side up or the other side down depending on whether you want the bike to run faster or slower over all, repeat. Do this several times back and forth till you have the idle speed you think will work and the carbs are balanced. These adjustments are made with the idle speed screws only.

After the idle is set the throttle cables are adjusted so the throttles both start pulling at the same time. This is sometimes done with other machines at 1400 rpm or 3000 rpm. Some riders try to set the higher rpm using the shorting rods. I just try to get both butterflys moving at exactly the same moment. Note the amount of slack at the throttle cable barrel on top of the carb where the adjustment is made. In theory both cables should have the same amount of free play. If you pull on the cable sheath at the top of the carb you can see it is free till it pulls the actual cable inside the sheath. You can see the free play by tipping the sheath ends to the side until they start to pull the throttle. Anyway the free play should be even and it should be as small as possible.

Go for a longer ride. You may have to repeat this process several times. Once the speed is stable and the bike idles you may now adjust the mixture screws a little but they should probably not be far off from the setting in the book. For your bike the book calls for 1 turn out on the mixture screw.

Do not ride the bike for any distances with the shorting rods attached. They will vibrate loose and cause ignition problems. I think your bike has an after market ignition of some kind? This is a very important warning for these ignition systems.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 11-05-2012, 04:49 PM   #87
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Quote:
Originally Posted by disston View Post
Balancing the carbs is a very important part of making the bike run as it should and smoothly. Unbalanced the bike will get poor gas mileage, be hard to start, be ruff and vibrate and even make unnatural noises. This is the key to making an Airhead run. It is some what an Art, maybe more Art than science. That can't really be true because these are machines but it's a fact that some tuners are better at it than others and it's hard to say why.

This is one method of balancing carbs. It involves shorting out the spark plug leads so the bike tries to run or does run on one side. You need this tool. You can buy it or you can make it yourself;



Sorry the picture is so small. These are for sale at Northwoods Airheads;

http://imageshack.us/a/img849/6267/t...img1229133.jpg

To make a pair of these tools use a long 4mm screw from the neighborhood hardware store. The screw is 4 x .7 and should be 60 or 70 mm long. The nipples that came with a new pair of spark plugs go on one end and you will also need a 4 x .7 nut to lock the nipple on the end. Leave enough thread of the nipple open on the end so the rod can be attached to a spark plug. The head of the screw is cut off so the plug wire can be attached to it. Tighten it down a little with a wrench, it will vibrate loose if not tightened. It is important that the plug wires do not become unconnected when the bike is running. They should be firing the plugs or be shorted to ground to not fire the plugs but they should not be just unconnected, that can cause ignition problems.

Once the bike is warm and the studs are connected with the bike at idle you short out one plug with a screw driver so the bike will run momentarily on one cylinder. Note the sound and speed of the bike on one cylinder. Take the screwdriver away and rev the throttle a little to clear pooled gas in the intake and then short out the plug on the other side. Note the sound and the speed of the bike on the other cylinder. If one cylinder is running faster than the other adjust the speed screws a little, either one side up or the other side down depending on whether you want the bike to run faster or slower over all, repeat. Do this several times back and forth till you have the idle speed you think will work and the carbs are balanced. These adjustments are made with the idle speed screws only.

After the idle is set the throttle cables are adjusted so the throttles both start pulling at the same time. This is sometimes done with other machines at 1400 rpm or 3000 rpm. Some riders try to set the higher rpm using the shorting rods. I just try to get both butterflys moving at exactly the same moment. Note the amount of slack at the throttle cable barrel on top of the carb where the adjustment is made. In theory both cables should have the same amount of free play. If you pull on the cable sheath at the top of the carb you can see it is free till it pulls the actual cable inside the sheath. You can see the free play by tipping the sheath ends to the side until they start to pull the throttle. Anyway the free play should be even and it should be as small as possible.

Go for a longer ride. You may have to repeat this process several times. Once the speed is stable and the bike idles you may now adjust the mixture screws a little but they should probably not be far off from the setting in the book. For your bike the book calls for 1 turn out on the mixture screw.

Do not ride the bike for any distances with the shorting rods attached. They will vibrate loose and cause ignition problems. I think your bike has an after market ignition of some kind? This is a very important warning for these ignition systems.

thanks for all that info! very greatful.

i fired up the bike again tonight, with the speed screws and mixture screws roughly set. Idles much better around the 1k mark.

Went for a short ride around the block, can definitely feel that they are not balance. So need to tackle that. But on a much more gloom side, after about 20 minutes of running and riding pretty good, all things considered, the bike like before starts bogging/coughing back firing and wanting to cut out.

So with Valves "set" (would rather have a pro make sure to call it properly set), carbs cleaned, intake rubber replaced. All that and the original symptoms still persist.

Now timing, is my next number one priority.
Yachtie is offline   Reply With Quote
Old 11-05-2012, 05:41 PM   #88
disston
ShadeTreeExpert
 
disston's Avatar
 
Joined: Mar 2011
Location: Silver Spring, Md
Oddometer: 8,372
You need to timing light to properly check timing at idle and also at 3000 rpm.

Th problems you now report are possibly the carb balance or the timing. You can find a cheap timing light at Harbor Freight, if you don't have one, and the shorting rods will help with the carb balance.

There are also other better methods but they also cost more for carb balance. You can find mention of an Inmates product in Vendors about the Harmonizer. This tool is the latest and greatest solution to the balance problem. It doesn't sound very cheap but actually there are more expensive solutions.

See how you do with the shorting rods.
__________________
.
Never memorize something you can look up.
---Albert Einstein

Pay your debt, piratejohn.http://www.advrider.com/forums/showthread.php?t=949341
disston is online now   Reply With Quote
Old 11-05-2012, 06:48 PM   #89
photorider
Gnarly Adventurer
 
photorider's Avatar
 
Joined: Nov 2008
Location: Chicago and Guatemala
Oddometer: 247
Did you check the sensor plate while you had the front cover off? Just try twisting it with your fingers. If it moves, that's your problem!
photorider is offline   Reply With Quote
Old 11-05-2012, 06:51 PM   #90
Yachtie OP
Gnarly Adventurer
 
Joined: Aug 2012
Location: Coral Springs, South Florida
Oddometer: 105
Quote:
Originally Posted by photorider View Post
Did you check the sensor plate while you had the front cover off? Just try twisting it with your fingers. If it moves, that's your problem!
I have this ignition now, and did not install it so really know nothing about it. Would my sensor plate still be there or does this ignition remove it?

http://www.euromotoelectrics.com/EnD...-p/edl-ign.htm
Yachtie 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 09:00 PM.


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