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Old 09-20-2013, 12:39 PM   #1
wiznas OP
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Diagnosing Intermittent Soul-Draining Problems?

I've got this super frustrating problem (or problems?) that causes my 1983 r65 to stall at seemingly random times and refuse to restart. I'll try to list all the little nuances of the problem incase something happens to be significant. I'm an 'optimistic noob' on mechanics, hoping to learn more and get to the bottom of this without going to a shop. But it is my first bike.

The big pain is that the problem is hard to replicate on command, or any time when it's convenient for bike fiddling. Above 60 degrees, the bike will start quick with full choke, usually first or second crank. I'll take the choke down to half after about 2 minutes and fully off after 2 more. I still usually keep the throttle cracked at stop lights for another 20 minutes or so until it's fully warm. This all seems normal to me, but let me know if you think otherwise!

Through this process, and even when the bike is warm, it does have a tendency to hiccup periodically, very brief instances of a loss of power and then itll go back to normal. Not sure if this is significant to the bigger problem.

I'll go for days without any problems and then all the sudden, with medium throttle, running smoothly, it'll cough and die. I can usually get it to briefly restart and sometimes limp off the road, where it almost always dies again and refuses to start, until I wait for 4-12 hours. There's often a single massive backfire in the dying process.

Usually the bike starts right up after a few hours and I can ride it home. So that makes me think maybe it's a heat related problem. It doesn't seem to be a vibration problem because it usually happens when the bike is smoothly running along paved roads. But sometimes the problem happens 1/4 mile from home, other times 10 miles. Sometimes I'll get to work fine, but itll do it on the way home. I don't think it has every happened after 30+ minutes of riding.

I had really funky sparks one time: one cylinder was sparking normal, and the other was sparking even before I hit the ignition button, and very erratically. So I took the gas tank off and found a lead to the ignition coil had a very tiny bit of movement. I cranked it down and had another 4 days of great riding and then it did it again this morning. This was on brand new plugs.

Other little maybe unrelated quirks:
-The tachometer doesn't work, it just sort of wiggles when I give it gas. (would love to hear a suggestion about this too if there are any ideas, but it's not as pressing as the other issue).
- The ignition coil looks like it's been replaced semi-recently, I believe it's the Dyna Brown module. Is there a problem that would burn up coils? Does anyone know what resistance I should measure through a good coil?
- The headlight has one of those flashing mods from the previous owner to be more visible. But it keeps the high beam locked on.
- And last spring it was REALLY hard to start in the cold.




Really appreciate anyone taking the time to read all that and any wisdom you might have, places to investigate or methods of diagnosis. Thank you so much!
daniel
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Old 09-20-2013, 01:05 PM   #2
guitstik
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Wiznas, How long have you had the bike? Besides new spark plugs, what other maintenance have you done to the bike. From what you are describing it sounds to be a fuel related issue but that is just conjecture without having the bike in front of me or knowing a bit more of its maintenance history. Do you have a visible fuel filter in the line? Do you shut the petcock off after riding? Have you ever flushed the the fuel tank and check the bowls for sediment?

There are any number of tings that it could be but since it doesn't seem tbe consistent or repeatable I would check the fuel system. On old bikes I tend to pay attention to what I am doing and when just in case I have to try to identify a specific cause/effect scenario. Like what I posted here http://www.advrider.com/forums/showthread.php?t=921296

In this case the common denominator that I determined both instances shared was a deceleration.
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Old 09-20-2013, 01:33 PM   #3
wiznas OP
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Hey thanks for the reply, I've had the bike about 10 months, but for the middle 6 I as away and didn't get to use it. I ran it a good bit in the fall of last year and then again in the summer.

2 months ago I drained the fuel tank into glass jars to look for junk but it all looked beautifully clear. It had an inline filter which also looked clean, but I was wondering if it was hindering fuel flow though, so I removed it as a test. No noticeable difference. I put some sea foam in the last tank and I think that did help the bike run a little smoother.

Apart from that, there hasn't been much maintenance.

Would a fuel problem be more consistent? The weirdness of it made me think electrical, but again, you are talking to a very entry-level moto mechanic!
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Old 09-20-2013, 02:05 PM   #4
guitstik
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It could be any number of things from fuel to electrical, from what you described my first thought was fuel. An electrical problem would be more cosistent the only caveat to that would be an intermittent short. Fuel is a little bit more tricky especially when working on old bikes. Carburetors that haven't been been well maintained can get foreign material in them that clog passages and starve the engine of fuel and either dissolve or get dislodged causing the intermittent problem. Rubber seals deteriorate and get gummy causing problems as well. Idle temps and running temps can vary greatly and so I would expect an electrical problem related to heat to be consistent with failure temps and usually at full operating temperature. Others may chime in with different ideas but I use a process of elimination process and go through only one system at a time. If you break any car/bike down into base elements you get fuel, electric and mechanical, by focusing on one at a time you minimze the confusion. Years of experience is helpful in determining where to start but a little common sense helps as well. You, yourself have already done that by thinking electrical so go in that direction and focus on only those parts that would/could cause your concern. As you go through it clean and lube all conections and eliminate any bad wiring that way even if that wasnt the cause you will know it shouldn't be a problem in the future.

One of the reasons I think fuel is that you said it takes anywhere from 4 to 10 hours to clear up. It doesn't take that long for a bike to cool down to resolve a heat related electrical problem and a short wouldn't clear up unles it is caused by expanding metal and even then time is again the factor. Fuel, on the other hand can take that much time. Sitting here typing this I'm wondering if maybe your tank isn't vented properly and its getting vapor locked. The next time it happens, open the fuel cap and see if it will start.
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Old 09-20-2013, 02:46 PM   #5
hardwaregrrl
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First I would remove the pilot and main jet. Check them and make sure there are no obstructions. Then I would measure float levels. Having to choke if that long seems like a blocked pilot circuit. Also measure the resistance of your plug caps. Remove the from the wires and they should read 5k ohms. Then check timing and valve lash.
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Old 09-20-2013, 02:49 PM   #6
SOLO LOBO
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Vapor lock? Are you riding with a tank bag perhaps?

Have you tried cracking open the gas than when it refuses to re-start?
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Old 09-20-2013, 03:09 PM   #7
Warin
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How does a fuel problem cause a back fire? One that only happens inconsistently?

--------------------------
Disconnect that tachometer .. it is directly connected to the coil and could cause problems there.

--------------------
When the bike fails .. you need to check things -
Fuel
Pull one float bowel off -- look for fuel in there and check for dirt.
If little/no fuel in the float bowel then open the fuel tank and check for vapor lock - listen to the opening for a sucking sound.

Electrics
Check for spark at the spark plug - no spark = electrical problem.

These are VERY basic things to check, especially if your waiting around for 3 to 4 hours .. you must have a very good book to read?
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Old 09-20-2013, 03:50 PM   #8
ritetwist
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My R65 gave me fits about a year ago.Key turned on, nothing happening,no functions.Very interment.
It quit firing a couple of times while riding it.
I would sometimes get it going by wiggling the key in the ignition.
When it was happening, I could sometimes get response by constant fiddling with the key,always got me home,though very frustrating.
I also noticed poor charging at this time.
I finally just changed out the key assembly.All has been good since.
A couple of weeks ago jpbellavance (on this forum) was asking how to get an ingition cartridge out.
Perhaps he had the same problem.
I don't know how to link a thread.
Good luck.
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Old 09-20-2013, 04:59 PM   #9
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Oddly enough I had the same trouble with my R100RS for about 3 months. Couldn't figure it out. Tried everything that the good peeps on this forum suggested.

Well... it turned out to be a pinched wire inside the front engine case. The wire that goes to the condenser was being shorted out intermittently while riding (pinched/vibration). I finally discovered this when my bike ran perfectly with the front engine cover removed, then didn't start with it installed.

Just sayin`, you never know.
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Old 09-20-2013, 06:07 PM   #10
_cy_
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Quote:
Originally Posted by wiznas View Post
I've got this super frustrating problem (or problems?) that causes my 1983 r65 to stall at seemingly random times and refuse to restart. I'll try to list all the little nuances of the problem incase something happens to be significant. I'm an 'optimistic noob' on mechanics, hoping to learn more and get to the bottom of this without going to a shop. But it is my first bike.

The big pain is that the problem is hard to replicate on command, or any time when it's convenient for bike fiddling. Above 60 degrees, the bike will start quick with full choke, usually first or second crank. I'll take the choke down to half after about 2 minutes and fully off after 2 more. I still usually keep the throttle cracked at stop lights for another 20 minutes or so until it's fully warm. This all seems normal to me, but let me know if you think otherwise!

Through this process, and even when the bike is warm, it does have a tendency to hiccup periodically, very brief instances of a loss of power and then itll go back to normal. Not sure if this is significant to the bigger problem.

I'll go for days without any problems and then all the sudden, with medium throttle, running smoothly, it'll cough and die. I can usually get it to briefly restart and sometimes limp off the road, where it almost always dies again and refuses to start, until I wait for 4-12 hours. There's often a single massive backfire in the dying process.

Usually the bike starts right up after a few hours and I can ride it home. So that makes me think maybe it's a heat related problem. It doesn't seem to be a vibration problem because it usually happens when the bike is smoothly running along paved roads. But sometimes the problem happens 1/4 mile from home, other times 10 miles. Sometimes I'll get to work fine, but itll do it on the way home. I don't think it has every happened after 30+ minutes of riding.

I had really funky sparks one time: one cylinder was sparking normal, and the other was sparking even before I hit the ignition button, and very erratically. So I took the gas tank off and found a lead to the ignition coil had a very tiny bit of movement. I cranked it down and had another 4 days of great riding and then it did it again this morning. This was on brand new plugs.

Other little maybe unrelated quirks:
-The tachometer doesn't work, it just sort of wiggles when I give it gas. (would love to hear a suggestion about this too if there are any ideas, but it's not as pressing as the other issue).
- The ignition coil looks like it's been replaced semi-recently, I believe it's the Dyna Brown module. Is there a problem that would burn up coils? Does anyone know what resistance I should measure through a good coil?
- The headlight has one of those flashing mods from the previous owner to be more visible. But it keeps the high beam locked on.
- And last spring it was REALLY hard to start in the cold.

Really appreciate anyone taking the time to read all that and any wisdom you might have, places to investigate or methods of diagnosis. Thank you so much!
daniel
where's plaka? he's really good at breaking these down...

intermittent problems are the worst .. could be electrical, fuel or mechanical.
so your first job is to determine which one of the three is causing your problems.
before drilling into details of that particular subsystem...

83 has a beancan with halls sensor, which can fail intermittently or fail completely. or someone could have replaced with aftermarket ignition. since someone has been in there with brown dyna coil 1.5ohm. indicating an electronic ignition is still there.

classic way to eliminate fuel as the issue, is to squirt starter fluid directly into carbs. the next time it dies .. and it starts immediately with a squirt of starter fluid. that's saying problems is fuel. if it makes no difference, it's not fuel while starter fluid is present.

check out fuel inlet screens, which can clog barely letting fuel through. take both line off and watch fuel delivery rates. drop your fuel bowls to check fuel when it dies, etc..

when chasing these intermittent problems .. go for the low hanging fruit first, before going to more complex issue.

you could have something simple as bad spark plug wires. what I use is a portable self contain ignition system which delivers a continuous arc to spark plug. which temporarily replaces ignition system. if bike starts and runs fine with portable ignition, then electronic ignition components is what gets chased down next. which includes bypassing ignition switch/safeties if any.

don't discount possibility you could have both fuel and ignition issue at the same time

_cy_ screwed with this post 09-20-2013 at 06:25 PM
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Old 09-20-2013, 06:36 PM   #11
bmwrench
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This is typical of hall sensor failure.
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Old 09-20-2013, 07:21 PM   #12
hardwaregrrl
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So, got any airhead friends that would let you borrow their bean can for a few days?? Maybe if you have an airhead wrench nearby you could rent one. Dunno where you're at in Virginia....but maybe contact Anton. Bet he'd lend you one for a small fee, and you may end up buying it from him. All you need is a timing light to reset the timing after the swap.
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Old 09-20-2013, 08:07 PM   #13
Renner
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I've had similar issues due to corrosion in the coil HT output socket.
Quick & easy check would be to remove the plug wire from the coil and look inside the 'tower'.
green = bad, copper = good

Also look closely and thoroughly at the coil body, checking for cracks.
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Old 09-20-2013, 09:14 PM   #14
Plaka
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Quote:
Originally Posted by _cy_ View Post
where's plaka? he's really good at breaking these down...

intermittent problems are the worst .. could be electrical, fuel or mechanical.
so your first job is to determine which one of the three is causing your problems.
before drilling into details of that particular subsystem...

83 has a beancan with halls sensor, which can fail intermittently or fail completely. or someone could have replaced with aftermarket ignition. since someone has been in there with brown dyna coil 1.5ohm. indicating an electronic ignition is still there.

classic way to eliminate fuel as the issue, is to squirt starter fluid directly into carbs. the next time it dies .. and it starts immediately with a squirt of starter fluid. that's saying problems is fuel. if it makes no difference, it's not fuel while starter fluid is present.

check out fuel inlet screens, which can clog barely letting fuel through. take both line off and watch fuel delivery rates. drop your fuel bowls to check fuel when it dies, etc..

when chasing these intermittent problems .. go for the low hanging fruit first, before going to more complex issue.

you could have something simple as bad spark plug wires. what I use is a portable self contain ignition system which delivers a continuous arc to spark plug. which temporarily replaces ignition system. if bike starts and runs fine with portable ignition, then electronic ignition components is what gets chased down next. which includes bypassing ignition switch/safeties if any.

don't discount possibility you could have both fuel and ignition issue at the same time
Why me? I can't add much to that. Anyway I was playing with a new toy. Anybody want an RT frame? You can cafe it and flip it and still call it an RT to get people to look at your ad. (I come by my rep as a sweetie honestly)

Carry a fresh spark plug in your pocket. Anything that's new. When it craps, put the plug ion the wire ground to fins and check for spark.

No spark = ignition issue. Spark figure fuel. Pull a carb bowl and see if its full of fuel.

I suspect ignition. If you have the pistons moving and no spark, the exhaust gets pumped full of flammable mix. One spark and you get a pretty good backfire. Wasted spark system. You get a spark with the Exhaust valve open. (I think, somebody correct me)

Snow bum has the field check procedures for ignition on his site. pretty simple. Take notes and carry them, with a jumper.

The poor connection at the coil is a prime suspect. I'd replace that w/ new.

Dyna brown is 1.5 ohm. Stamped on back.

New plug wires are never a bad idea. If they fix it you're done, if not, put them on the shelf until you need them, No money lost there, that day will come.

If the tach doesn't work, disconnect it. All three wires in the pod. Tape them. I think the feed is off the ignition module plug. It's common with the coil trigger. If the connection is at the coil, kill it there. Would be a black wire I believe.


Without stabilizer, gas lasts a month. Seafoam and StaBil are stabilizers. Gas changes in formula seasonally. Don't run summer gas in the winter and vice versa.

I would get it reliable, then go after the cold bloodedness---if it is still there.

Is that coil a 6 volt or 12 volt? I would consult Rick at Mottorad Electrik on this. He sells them. See if that is what you want for a stock ignition module. I run two of them in series (dual plug)

Good sparks are fat and blue. Bad ones are small and yellow.
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Old 09-21-2013, 06:05 AM   #15
wiznas OP
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Great! So much good info, thanks so much guys! Heading out to rescue the bike this morning. Last night was the first night it failed to restart after a few hours. Which is annoying but at least it makes it easier to diagnose. I don't think it was a vacuum lock in the tank, because I checked in there for fuel the first time it cut out and it still wouldn't restart.

My hunch is still electrical, but I'll definitely check the float bowls next time just to be sure. Thanks again for all the wisdom, I'll post again when I find the culprit.

p.s. I'm in Lynchburg Virginia, if anyone airhead wrenches are in the area, I can barter some handmade goods or something for your troubles!
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