bike running on 2 cylinders again

[andrewclaycomb]

Ok so after switching over to a dyna s ignition, dyna 3 ohm coils, new plugs, wires, caps, I broke down and ordered an OEM mechanical Advancer the bike has gone back to running on 2 cylinders. I pulled the plugs and they are sooty black so I'm thinking I fouled plugs. I change the plugs and I'm still only on two cylinders. Any ideas on where to start. Cylinders 1 and 4 are the dead and these are the same ones that were dead before the new ignition.


The bike was running great for about a week after everything was done. I tried putting seafoam right away it ran weird for the first tank but awesome once it was dilluted down with another tank.


It also seems like once you fix one leak you find 2 more on this bike. Tach drive was leaking, now the master cylinder developed a crack after fitting stainless brake lines and somewhere along the bottom of the motor right above the collector of my new chrome exhaust there is an oil leak. Between that oil leak and the tach oil leak I can safely say that my GS hates my new Vance and Hines 4 into 1. Its got burnt oil on the headers and now the collector. Next time I'm getting black pipes.

[mark]

One thing at a time I guess. I'd start by switching my coils in order to see if the problem switches to 2 -3 and checking the orange wires that go to the coil for proper voltage.

[GS850_Coug]

Make sure you are getting full battery voltage to both coils. Also check the circuit and cdi to make sure the signal is getting to the suspect coil.

[andrewclaycomb]

alright so i finally got around to switching the coils around and all 4 cylinders are running. so what is the problem here. Should I replace a wire on the wiring harness maybe?

The 2 cylinder thing was off and on so I'm thinking i've got some loose wiring somewhere.

[GS850_Coug]

Mess with your wires some more while the bike is running (if you can) or with an ohmmeter attached to each end until you find the one (or several) that give you erratic readings. Then repair that wire or connector. Atleast you've got narrowed down to a cheap fix!

[mark]

I had that problem briefly with my Dyna S. Turned out to be that the coils were not grounded to the frame well. I filed around where the coils bolt to the frame and they worked from then on.

[andrewclaycomb]

Maybe I'll try sanding around were those coil posts bolt up. I never realized they grounded directly to the frame. I even think they are painted there.


I'm just glad this is a cheap fix. I was prepared to part out if I had to replace too many parts.

[Commodus]

I found it too annoying to ensure a reliable ground through my powdercoating. I just ran a wire to the engine, between the carbs. You may wanna do the same.

[andrewclaycomb]

ok it started happening again today. I had all of the coil posts wired together to ensure a ground to the left coil from the right side but today i was running on 2 cylinders after riding for about 2 hours. Luckily I carry all the tools to flip the coils in my tank bag and after swapping the coils it ran fine long enough for me to get back on the highway to head home. On the ride home it kept dropping 2 cylinders so i would pull over, the bike would completely die and i would try to start it again. I would crank on the igntion for a few seconds and it would eventually backfire and then all 4 cylinders would run like normal for a little bit longer until the same thing happens. This happened 3 times during a 15 minute trip traveling at 65 mph. I'm starting to get tired of this ignition problem. cylinders 2 and 3 are working fine all the time regardless of which coil is hooked up. Can i ground the coils directly to the negative side of the battery? Wouldn't wiring the posts of both coils together eliminate a ground problem?

[earlfor]

None of the coil terminals are supposed to be connected directly to ground. Thats the same as intentionally wiring a dead short into your ignition system. I'm surprised it runs at all, anytime. You have two sets of points with a condensor for each pointset. The left pointset fires cylinders 1,4 and had its own coil. The right pointset firest cylinders 2,3 and has its own coil.
In essence, your bike has two SEPARATE ignition systems, one for each cylinder pair. You cannot wire them together at any point. Power is supplied to the coil by a 12v positive orange/white wire. That is the + terminal of the coil and input. The other terminal of the coil is 12 v POSITIVE output (commony referred to as the negative terminal, but it IS 12V POSITIVE output) This 12+ runs to the points, When the points close, they make the ground connection to complete the circuit. Your problem most likely is the pointset on the 1,4 side is either burned, pitted, or out of time. Replacing or adjusting the left pointset will also require adjusting/retiming the right pointset because the right set is mounted on an adjustable half breaker plate that moves with the full breaker plate used to adjust the left set. Replace both your pointsets and condensors, set the gap and timimg and your problem will most likely be solved.

Also, to cover all the bases, take your multimeter and with the ignition switch on, and the orange/white wires disconnected from the coils, measure the voltage available on each orange/white wire. It should be close to the same as battery voltage. Also, check your coil resistance. Resistance between the two terminals on each coil should be around 5 ohms. Set your meter to the lowest ohm scale that includes a 5 ohm reading. Next, check the resistance between the contacts in the spark plugs caps 1 and 4 and then between 2 and 3. Set your meter to a scale that will read up to 100,000 ohms.
The resistance between the spark plug caps should be between 30k and 50K ohms (30,000 and 50,000)

E.

ok it started happening again today. I had all of the coil posts wired together to ensure a ground to the left coil from the right side but today i was running on 2 cylinders after riding for about 2 hours. Luckily I carry all the tools to flip the coils in my tank bag and after swapping the coils it ran fine long enough for me to get back on the highway to head home. On the ride home it kept dropping 2 cylinders so i would pull over, the bike would completely die and i would try to start it again. I would crank on the igntion for a few seconds and it would eventually backfire and then all 4 cylinders would run like normal for a little bit longer until the same thing happens. This happened 3 times during a 15 minute trip traveling at 65 mph. I'm starting to get tired of this ignition problem. cylinders 2 and 3 are working fine all the time regardless of which coil is hooked up. Can i ground the coils directly to the negative side of the battery? Wouldn't wiring the posts of both coils together eliminate a ground problem?

[andrewclaycomb]

I don't have points any longer I'm running a dyna s system.

[earlfor]

It makes no difference, you still cannot connect the two coils together as the functions are exactly the same. Still do the coil and plug check and check timing on the 1,4 trigger with a timing strobe. If timing is correct, then you most likely have a faulty crank trigger.

The big killer of electronic ignition systems is faulty R/R's that reach charge rates in excess of aprox 15-16 volts.

E.

I don't have points any longer I'm running a dyna s system.

[andrewclaycomb]

This is why I got the dyna setup. The old points stopped firing cylinders 1 and 4. After changing it, everything worked great for a while. A few posts ago some people recommended a problem grounding to the frame that's what I wired together. Just wher they bolt to the frame. I wrapped wire around each bolt and then ran it to the opposite coil bolt. I guess it is possible that the dyna ignition could be faulty but its a weird coincidence. Is there a way for me to check the wiring harness?

[andrewclaycomb]

How do I check what its charging at?

[earlfor]

OK then, all you did was connect a wire between the frame mounting bolts on the coils. That is fine, shouldnt be necessary, but it cant hurt anything. I misunderstood you to be saying you had wired jumpers connecting all your coil terminals together. LOL

Basically, Dyna ignitions do not simply "become" faulty. There is a cause.
The most common reason for Dyna failure is too high a voltage power supply.
The most common reason for too high a charging voltage is a faulty R/R.
The Dyna is meant to operate at aprox 12 volts. It will tolerate occasional brief surges to about 15 volts. Continuous running in the 15 volt range will shorten its life. The higher the voltage, the shorter the lifespan. The wiring harness will not cause high voltage. Due to corrosion or resistance and poor connection, it can cause low voltage, but never high voltage. Voltage level is the domain of the charging system and in particular the R/R.

Your bike was made with a separate regulator and rectifier. The rectifier will be mounted on the plate under the left sidecover. The regulator is mounted upside down on the underside of the battery box. Have you upgraded your regulator/rectifier components to the newer self contained/all in one R/R? You should.

Now to check regulated voltage, set you multimeter to the DC 20 volt scale.
Connect the red probe to battery positive and the black to battery negative. Start and run the bike. Rev it up to 5k rpm and hold it for about 5 seconds. It takes that long for the R/R to stabalize at a voltage level.
At 5K rpm, the voltage should not exceed about 14,8 at any point and should settle to something in the 13.5 to 14.2 volt range depending on your battery state of charge. With a fully charged battery, I usually show about 13.4 volts at 5k rpm on my bike. If voltage at any time exceeds 14.8, the R/R is faulty.

E.

This is why I got the dyna setup. The old points stopped firing cylinders 1 and 4. After changing it, everything worked great for a while. A few posts ago some people recommended a problem grounding to the frame that's what I wired together. Just wher they bolt to the frame. I wrapped wire around each bolt and then ran it to the opposite coil bolt. I guess it is possible that the dyna ignition could be faulty but its a weird coincidence. Is there a way for me to check the wiring harness?