ed r65 update

[mjbickford]

ed, did my bean can get to you and get installed yet?  

I awaiting news if it fixed your problem.

[Ed Miller]

Hey, don't rush me!    I ran the Hood to Coast over the weekend, and didn't get much work done on anything.  I did get the bean can and hope to try the experiment pretty soon.  

Now that you've asked, everybody will want to know the whole story.  Sigh.  Later.

But if you're on the Airlist, it's been discussed a while back under the topic surging.  I haven't heard back from the other guy on the list with a similar problem, to see how he's faring either.

[Bob_Roller]

Ed, I'm sure you will let us know what's going on later, but just a little warning if you are going to test the 'bean can', I'm assuming that it is the electronic type, not contact breaker type. The maximum current that the Hall Effect sensor can handle is in the area of 22 ma. Any appreciable amount more , and damage will likely occur. I don't know the manufacturer of the original sensor that BMW uses, but the common replacement is a Honeywell 2AV54, Newark Electronics has them, and they have spec page for voltage range, and current limits, operating temp range, etc.

[Ed Miller]

Thanks Bob, but I'm going to do the simplest test:  I'm going to swap mine out for a known good one; if my weird surging symptoms persist I know I don't need to repair my can and I'll continue to drive myself crazy trying to find an air leak in my intakes.

[mjbickford]

I ran the Hood to Coast over the weekend, and didn't get much work done on anything.

oh, well i had to feed a bunch of you... 950 for breakfast and wednesday and thursday, then 2000 for a spaghetti feed thursday night.

at least the paycheck covered the mortgage this month.

[Bob_Roller]

Ed, I was talking to another airhead rider at work over the weekend, and he mentioned that the emissions system can cause a problem, I guess there is a diaphragm in the valve in the air-box, and it is connected to the carb by the vacuum line from the carb. There is the possibility of the diaphragm being bad, and causing a vacuum leak , if you still have the emissions system installed. I don't know if this may be your problem or not, but possibly another place to look at.

[Ed Miller]

Thanks Bob.  I checked that a while back by removing the vacuum sampling tubes, capping the vacuum ports, with no change in performance.  I've also tested the diaphragm you're talking about with a vacuum pump and it held vacuum.

If anybody is interested, for some time I've been trying to trace down the cause of a warm weather, mid rpm range surging problem, say from 3800 rpms to up over 5,000.  It could be better described as a stalling, not a surging problem, but I haven't come up with a good way to even ask the question.

The other day I put my timing light on the wires and get a nice, smooth flashing even at the rpm range where the problem manifests, so I'm still thinking some vacuum leak instead of ignition problem.  Snowbum mentions that if the choke housing isn't sealing well that can cause surging from 30 - 50 mph, so I'll investigate that next, before I do the bean can swap.

[Ed Miller]

Mike, you're in luck, I changed the ignition canisters today, and the bike still did it's irritating surging/stalling thing.  It was over 90 today so I didn't have to ride far to feel the effects.  I guess I'll post a new thread, describing all I've done, to see what anybody suggests, and to have a place to copy text and send it to Oak or somebody.  Umm, no offense to this forum.....

[Bob_Roller]

Ed , is this a problem that has just recently happened, or is it something that you've had since you had the bike ?

[Ed Miller]

Cool Bob, quick reply.  Please see my new thread.  It's been a long time coming.  

[tagordon]

Just a thought - hot air = less oxygen.

[Ed Miller]

Hmm, so maybe the stock jetting is a tiny bit, a very tiny bit, rich for my bike?

I just remembered, I have a different snorkle on the airbox than what the bike came with.  The one I put on has two different sized tubes, whereas the original one had them the same size.  I put it on to see if I could feel any difference, couldn't, but never bothered to put the originals back on.  I'm grasping at straws now....  But I'll put the originals back on.

[Bob_Roller]

I would email Oak with what you have, and what you have done so far. I've sent a few emails to him over the past 5 years or so, and he is one of the most knowledgeable persons on BMW Airhead bikes around. He might not get it spot on ( kind of hard to diagnose a problem from a distance), but he can usually get to the general area where the problem is, or at least give you a good idea where to start looking.