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Old 04-10-2013, 08:49 AM   #16
Highwood OP
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Location: Banff, AB
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Thanks - More Data

Thanks for the suggestions and links.
More twiddiling in the garage last night revealed the following:

Timing: There is a "ghost image" at the s mark (idle timing mark) giving me two lines and two dots, perhaps a degree or two apart. The ghost image is kind of like someone rapidly shaking a pencil. I taped the weights closed (no advance possible) and retested and still had a ghost image. I take this to mean that ignition timing is not identical on both sides.

ATU: Clean. Spring return is good. Everything loose and easy moving. With a timing light, advance (weights out) and return (weights in) seems smooth, though perhaps a slight "hang" on the last moment of return (less than 1500 rpm), but it was late, I was tired and if there was a hang, it was mild and brief. Advance shaft is smooth over its entire depth and has no horizontal streaks or marks, suggesting to me that it is not unduly worn. Bike only has 44K kms (27.5k miles).

Points: Gap seems to be too narrow. .35mm gauge will not fit. Removed and inspected. They look pretty vintage, pitted on both sides, but the pitting seems relatively centered. Pitting has not eroded the edge of the contacts, just the centre. The black rub bar seems quite short (but I have nothing to compare to except past dealings with old Fiats and Porsches.)

Plugs: Quite black and sooty, as distinct from oily. Consistent with a "rich" condition or poor ignition according to my Haynes manual. Plugs are a perfect match to the picture in the manual. That may have been due to my carb settings, rather than the tech's carb settings. I only have about 150 kms on the bike since the tech set the valves and carbs.

Timing Chain: I assume if the problem (different ignition timing side to side as indicated by the ghost image at idle) is timing chain slop, I would hear it with my head between the wheel and the front cover, or laying under either cylinder. There is no slapping, clanking or chain-like noise, just a gentle tick-tick of the valves.

Camshaft Nose: Shaft looks good. No visable signs of wobble or bending. How does one determine if the camshaft nose is out of true?

Exhaust: Bike has two-into-one exhaust installed by previous owner. Metal gaskets and fin nuts are good, tight and leak free. Heat feels "equal" from both cylinders, but I can juggle baked potatoes. I don't trust myself to be able to determine if one side is hotter than the other.

Intake: WD40 test shows no leaks. Vacuum port screws snug and seated. No air or vacuum leaks at the carb or manifold.

Choke return is to full stop on both sides.

I'm gonna chase down new points and a new condenser, install, gap correctly, check and adjust timing and report back.

If new points and condensor result in the same idle ghosting, I will also adjust idle downwards (screw out) to see if I can reduce the warm, not hung, idle and report back. I can imagine a scenario where too fast at idle would result in a rich condition. I can also imagine a scenario where high idle would increase as bike got warm, especially if the "transfer ports" are engaged.

Regarding the question of hard riding, I am gentle with the bike until I can turn the choke fully off, about 2-3 kms. After that, I use 2nd and 3rd gear and my right hand. Part of the point of a motorcycle is to get through traffic efficiently. I'm not cruising generally. I am briskly accelerating and decelerating through traffic, pulling the engine near redline regularly. The "hang" seems related to the last steady-state throttle position. At fast or hung idle, the engine still feels and sounds balanced. There is no right-hand torque or unusual vibration.

I have an R12GSA for making miles. I use the Airhead around town as a cool, relatively-high-speed grocery getter and errands mobile. That being said, I am the only guy I know with an airhead. I have never ridden another airhead. My impressions may lack context.

I am out of town for a week, so if I go dark, it just means I haven't had time to do the work. I'll report back at my earliest.

Sincere thanks for the suggestions, thoughts and links.
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Old 04-10-2013, 09:01 AM   #17
Plaka
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Quote:
Originally Posted by Highwood View Post
Thanks for the suggestions and links.
More twiddiling in the garage last night revealed the following:

Timing: There is a "ghost image" at the s mark (idle timing mark) giving me two lines and two dots, perhaps a degree or two apart. The ghost image is kind of like someone rapidly shaking a pencil. I taped the weights closed (no advance possible) and retested and still had a ghost image. I take this to mean that ignition timing is not identical on both sides.

ATU: Clean. Spring return is good. Everything loose and easy moving. With a timing light, advance (weights out) and return (weights in) seems smooth, though perhaps a slight "hang" on the last moment of return (less than 1500 rpm), but it was late, I was tired and if there was a hang, it was mild and brief. Advance shaft is smooth over its entire depth and has no horizontal streaks or marks, suggesting to me that it is not unduly worn. Bike only has 44K kms (27.5k miles).

Points: Gap seems to be too narrow. .35mm gauge will not fit. Removed and inspected. They look pretty vintage, pitted on both sides, but the pitting seems relatively centered. Pitting has not eroded the edge of the contacts, just the centre. The black rub bar seems quite short (but I have nothing to compare to except past dealings with old Fiats and Porsches.)

Plugs: Quite black and sooty, as distinct from oily. Consistent with a "rich" condition or poor ignition according to my Haynes manual. Plugs are a perfect match to the picture in the manual. That may have been due to my carb settings, rather than the tech's carb settings. I only have about 150 kms on the bike since the tech set the valves and carbs.

Timing Chain: I assume if the problem (different ignition timing side to side as indicated by the ghost image at idle) is timing chain slop, I would hear it with my head between the wheel and the front cover, or laying under either cylinder. There is no slapping, clanking or chain-like noise, just a gentle tick-tick of the valves.

Camshaft Nose: Shaft looks good. No visable signs of wobble or bending. How does one determine if the camshaft nose is out of true?

Exhaust: Bike has two-into-one exhaust installed by previous owner. Metal gaskets and fin nuts are good, tight and leak free. Heat feels "equal" from both cylinders, but I can juggle baked potatoes. I don't trust myself to be able to determine if one side is hotter than the other.

Intake: WD40 test shows no leaks. Vacuum port screws snug and seated. No air or vacuum leaks at the carb or manifold.

Choke return is to full stop on both sides.

I'm gonna chase down new points and a new condenser, install, gap correctly, check and adjust timing and report back.

If new points and condensor result in the same idle ghosting, I will also adjust idle downwards (screw out) to see if I can reduce the warm, not hung, idle and report back. I can imagine a scenario where too fast at idle would result in a rich condition. I can also imagine a scenario where high idle would increase as bike got warm, especially if the "transfer ports" are engaged.

Regarding the question of hard riding, I am gentle with the bike until I can turn the choke fully off, about 2-3 kms. After that, I use 2nd and 3rd gear and my right hand. Part of the point of a motorcycle is to get through traffic efficiently. I'm not cruising generally. I am briskly accelerating and decelerating through traffic, pulling the engine near redline regularly. The "hang" seems related to the last steady-state throttle position. At fast or hung idle, the engine still feels and sounds balanced. There is no right-hand torque or unusual vibration.

I have an R12GSA for making miles. I use the Airhead around town as a cool, relatively-high-speed grocery getter and errands mobile. That being said, I am the only guy I know with an airhead. I have never ridden another airhead. My impressions may lack context.

I am out of town for a week, so if I go dark, it just means I haven't had time to do the work. I'll report back at my earliest.

Sincere thanks for the suggestions, thoughts and links.
Pressed for time at the moment.

You have bent cam nose. The symptom is the double image. Confirm it with a dial indicator if you want.

Not likely to be your problem. You can kind of split the difference when timing it or Try to straiten the nose (interesting thread on that recently), or fit an electronic ignition. I chose the last on my /5 as I was dual plugging anyway.

Do plug chops to evaluate the mixture when you are running at speed and having the problem.

Know what a points file is?
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Old 04-10-2013, 09:52 AM   #18
190e
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Quote:
Originally Posted by Highwood View Post
Plugs: Quite black and sooty, as distinct from oily. Consistent with a "rich" condition or poor ignition according to my Haynes manual. Plugs are a perfect match to the picture in the manual. That may have been due to my carb settings, rather than the tech's carb settings. I only have about 150 kms on the bike since the tech set the valves and carbs.

Plugs can't be read reliably if the choke has been used as it can soot them up even when the normal running mixture is correct. Most reliable method is to put clean plugs in engine that's already hot. Having said that I'm not too keen on risking the threads when the engine is hot so if it's possible start and run without choke I prefer to do that.
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Old 04-10-2013, 09:57 AM   #19
Highwood OP
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Quote:
Originally Posted by Plaka View Post
Pressed for time at the moment.

You have bent cam nose. The symptom is the double image. Confirm it with a dial indicator if you want.

Not likely to be your problem. You can kind of split the difference when timing it or Try to straiten the nose (interesting thread on that recently), or fit an electronic ignition. I chose the last on my /5 as I was dual plugging anyway.

Do plug chops to evaluate the mixture when you are running at speed and having the problem.

Know what a points file is?
I believe the pitting is too severe to be addressed with a points file. Just ordered points and condenser for arrival late next week.

I'm uncertain what you mean by "do plug chops to evaluate the mixture." Help please.

There is no ghosting at the full advance mark with the old points, just at idle. Does that change your view on the bent camshaft nose? Alternatively, given no ghosting at full advance, does that mean the bend is small enough not to be having a significant impact? Or, does the bend mean that carb balance is virtually impossible because one is using mixture to try to compensate for unequal left to right ignition? Is it possible there is a bearing going that could cause the camshaft nose to wobble? Can that bearing be fixed easily?

I'm reluctant to throw $300 at an electronic ignition, but I love the bike. Is there consensus on the best electronic ignition? Dyna or Omega? Or, are both good and I am asking the equivalent of "what oil should I use and how often should I change it?"

Thanx for your help.
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Old 04-10-2013, 10:17 AM   #20
disston
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A ghost of one or two degrees is supposed to not be a problem. I think I read that on Snowbum's site when I was dealing with this problem some years ago. But in principle I will tell you that it would bother me. I ended up with a solid image, no ghost, after doing the bent cam tip explained on the Duane Ausherman site.

http://w6rec.com/duane/bmw/timing/

That link is for the article about the double timing image. There is a lot of info on the DA site but this article is hard to find. He is talking about /2 BMW's but the principle is the same. It might be a good thing to point out that a timing image that spans the beginning of one tooth of the flywheel to the beginning of the next tooth is more than 3 degrees.

At one point I had the double images touching each other but I was able to get them closer than this. When I started the images were so far apart that it looked like one image till the throttle was raised and the second image could be seen. My BMW sounded more like the lope of V twin motor (you know what I mean?)
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Old 04-10-2013, 11:04 AM   #21
Highwood OP
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At one point I had the double images touching each other but I was able to get them closer than this. When I started the images were so far apart that it looked like one image till the throttle was raised and the second image could be seen. My BMW sounded more like the lope of V twin motor (you know what I mean?)
Yes, I do know what you mean. It DOES NOT sound like a V twin. The ghosting at idle is less than a 1/4". There is no ghosting at full advance.

From Duane A. "How much error is too much? That is up to you. We found little, if any, improvement if the two marks are brought together from only 1/4" apart. .... The final indicator is the "F" mark. If it is good and the "S" is a bit out, forget about it. It is one of those things in life. "

Sounds like I have "one of those things in life." I am too brutal with a hammer, and frankly too afraid, to try the fix idle ghost. I will take the advice of forgetting about it, particularly given the close proximity of the ghost (less than a 1/4" (maybe 1/8) and both s marks well within the window).

Thanks for the link and advice.
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Old 04-10-2013, 11:32 AM   #22
disston
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Quote:
Originally Posted by Highwood View Post
Yes, I do know what you mean. It DOES NOT sound like a V twin. The ghosting at idle is less than a 1/4". There is no ghosting at full advance.

From Duane A. "How much error is too much? That is up to you. We found little, if any, improvement if the two marks are brought together from only 1/4" apart. .... The final indicator is the "F" mark. If it is good and the "S" is a bit out, forget about it. It is one of those things in life. "

Sounds like I have "one of those things in life." I am too brutal with a hammer, and frankly too afraid, to try the fix idle ghost. I will take the advice of forgetting about it, particularly given the close proximity of the ghost (less than a 1/4" (maybe 1/8) and both s marks well within the window).

Thanks for the link and advice.
I think that is the right decision given that the ghost is gone by the time of full advance. Full advance is much more important than idle.

The procedure is scary. I had those feeling also but having done it I am more confident.

I think it may go away completely with the new points.
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Old 04-10-2013, 12:29 PM   #23
supershaft
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To fix the fast idle all you need to do is adjust your idle screw and mixture screw when the engine is good and hot. After you do that, it won't idle like it was when it is cold but who rides around with a could engine?
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Old 04-10-2013, 12:51 PM   #24
Les_Garten
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First things I would confirm:

When it is doing the behavior

1) Push on the linkages on the carbs for the butterflies and chokes and make SURE they are in idle and off positions. This is the very first thing that absolutely has to be put to bed. You want to know if your carb shafts or linkages or cables are out of whack or not.

2) I've never used WD-40 to check for vacuum leaks, but it doesn't impress me much from the sound of it. One thing that will work well if you have one is a Torch with a pencil type tip with Map Gas. This is really nice because you can regulate flow, turn it off and on and very finely direct the flow. I have one like the one below and it is really handy for this.



3) CONFIRM there are no vacuum leaks especially around the spigots.

4) If you have a timing light, check the timing if you think it is sticking in some strange fashion. A programmable timing light would be the shiznit here.

Here is the one I use(very handy):



Now quit goofin' around and figure this bad boy out and don't leave us hangin'!
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Old 04-10-2013, 01:04 PM   #25
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If you are going to evaluate your plugs by using the "chop" method, get some ethanol free gas. Usually can find it at gas stations near a lake and a set of new plugs.

plug chop
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Old 04-10-2013, 01:39 PM   #26
supershaft
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IMO, 99% of everybody has no business doing plug chops. If they can afford all the plugs to do anything close to real comparisons, most everybody still thinks too rich is too lean. IMO, forget it. Go by how it runs and the piston crown IF you are really tuning it for best power. Anywhere close to best power and new plugs will be mostly all white.

Vacuum leak? That's usually at the carb spigots that have already been mentioned but what about the enricher body gasket? That's the other most likely source.

The OP needs to get some points and adjust his timing but the fast idle is most always simply about adjusting the idle AFTER the engine is FULLY warmed up. His description of how it idles cold tells me with some certainty that he has not done that.
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Old 04-10-2013, 02:09 PM   #27
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Originally Posted by supershaft View Post
..................adjusting the idle AFTER the engine is FULLY warmed up. His description of how it idles cold tells me with some certainty that he has not done that.
Is that likely given a idle rpm of up to 3000?

and what of the idle returning to normal after turning off, and restarting?
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Old 04-10-2013, 03:15 PM   #28
Highwood OP
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More Thanks

Thanks for the link to a description of "plug chopping." I'll give that some thought. There's lots of wide open prairie to the east.

Before I do anything else, I need to get properly-gapped, non-pitted points, a good condenser and the timing set. Then I'll go for a proper run and see if I can recreate the problem.

I have a suspicion that it is a multi-issue problem (points, timing, atu, idle screw, mixture screw), therefore requiring a disciplined approach. If I change too many things at once, I won't know what made a difference. I do believe the key is a very full warm up. I suspect I'll be riding around with a screwdriver and a manometer for a while.

Off for four days with my sweetie. Points and condensor won't be in until late next week earliest. Those that are helping deserve, at the very minimum, to know how it turns out. I promise to report back post points and timing.
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Old 04-10-2013, 03:41 PM   #29
supershaft
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Is that likely given a idle rpm of up to 3000?

and what of the idle returning to normal after turning off, and restarting?
Carb adjustment, carb adjustment, and carb adjustment.
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Old 04-10-2013, 06:25 PM   #30
photorider
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I can't remember if this has been brought up but are your throttle cables in good shape?
I've seen throttle cables ruined by being careless when removing the carbs. This can also cause the idle to "hang."

Did the throttle shaft o-ring get replaced when you rebuilt the carbs (often they are not)? They can also cause a condition similar to what you describe.

Good luck with the diagnosing and let us know what you find.
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