New coils - still lose 1&4 after bike is hot

[chef1366]

Start the bike with a remote tank or you fuel tank on a trash can or something. Idle it up until it doesn't stall.
Adjust the mixture screws in slowly until the bike starts to decrease in RPMs. Then take out the screw a half turn.
They will all be close but different. If one makes no difference in idle or is way too far out the carbs need cleaned or the valves need adjusted.

[Fergie]

Well, I am at my wit's end!

On the way home for lunch just now, I made it about 2 blocks before 1&4 cut out. I pulled to the side, and checked for spark at the outboard cylinders...nada.

A "bike mechanic" stopped and took a look at the bike after a brief explanation of the problems. He told me, and I quote: "You need to get your petcock rebuilt, or check your vacuum line. I put it on "PRI" so the fuel is flowing freely, and that should get you home." He also reached under the tank and turn a large screw a few times. This allowed the bike to idle, even with 2 cylinders not firing.

I made it home, but about 1 mile away from home, it was like a switch was flicked, and #1 and #4 came back to life! I rode home, and then while pulling into the driveway, #1&#4 cut out again!

Good grief this should be so difficult to track a problem down! I'm to the point that I want to sell the bike and be done with it! I'm tired of having to push the bike to the side walk at an intersection!

Also, while I had it in the driveway, I checked a few things. The stator resistance between legs was 1.8 ohms, and infinity to ground. AC voltage between the legs, at 5000rpm, was 70Vac. The battery at idle was 12.30v, and at 5000rpm it was 12.8v.

For those that are interested, check the FS section later!(jk)

[Fergie]

I just spoke with a local bike shop, and explained everything that is going on to him. He seems to think that the Dyna might be problem, that when it heats up, the resistance increases and I lose the outboard cylinders.

Anyone else care to weigh in?

Thanks,
Gavin

[BassCliff]

Hi,

A thermally intermittent part is always a possibility. Unfortunately, about the only way to test is to replace parts, or return to stock, and see if it runs better. It's part of the "process of elimination". Sometimes it's very inconvenient.


Thank you for your indulgence,

BassCliff

[tx2000bob]

Anyone else care to weigh in?

Thanks,
Gavin

I'm not an expert. But it seems to me that if you have the bike in the state where 1+4 are not firing, you might want to take another run at it. 1. With the engine not running, re-verify that there is no spark. 2. Try putting a battery charger on the battery to boost the system voltage to 13-14 volts and see if it makes any difference as far as the 1/4 spark. 3. Verify that in this state (ignition on, 1/4 not firing) that the 1/4 coil has voltage on the primary. Normally the primary should have 12 volts on it. With points, there would be a significant portion of the rotation where the points are open and the coil would not have current flowing on the primary, but I'm guessing that with the Dyna ignition the "open dwell" is very short, regardless of rpm (if it's short enough, it will be difficult to see with a meter or trouble light). Once for each revolution, the dyna ignition should open the coil primary, and the voltage on the primary should change slightly (not the 12V side, but the switched side going to the dyna), but this may be difficult to see as you're cranking it (unless you have an oscilloscope?) because the period of time will be short (I'm guessing) when the primary is open. 4. You may want to compare behavior (with a meter, or trouble light, or whatever you're using) between the 2/3 coil and the 1/4 coil primaries as you're cranking (again, look at the switched side, not the 12V side). 5. I know you said you replaced the coils, but if you're unsure about the coils try swapping the 2/3 with the 1/4 coil and see if the problem moves or stays on 1/4. Alternatively, if there is 12V on the coil you can try disconnecting and reconnecting the 1/4 coil primary, and you should see sparks on the 1/4 plugs. 6. If all of the above looks good (coil primaries have 12V, no difference in primary open/close characteristic, no change in behavior when 1/4 coil is swapped with 2/3 coil) then the most likely remaining suspects are either a bad connection somewhere (recheck connections from dyna to coils, especially) or a faulty dyna ignition (perhaps when it heats up). Again, you'll have to do most of this when the system is actually in the failed state. If that's difficult/impossible, try taking a hair dryer to the dyna ignition and heat it up while you're looking at the 1/4 spark. See if the spark goes away at any point. If you're doing a lot of cranking, you may want to ease things on the starter motor by removing all your plugs. In any event let the starter motor rest, and don't crank it for an extended period of time. Try to keep your cranking cycles to 5 seconds or less.

You might also want to review the Dyna install instructions. They give an abbreviated troubleshooting process which may be of interest. Basically the steps I wrote above will cover it. Not sure which model you have but this seems relevant:

http://www.starracing.com/Star/documents/DS3-1_3-2.pdf

Actually after reviewing the dyna instructions for static timing, it does appear that the coil primary current will switch off and stay off at certain points in the revolution. So this should be a fairly easy method of seeing if the dyna is working or not. But it will need to be in the state where 1/4 are not firing to be useful.

[Fergie]

I'm back!

I've been swamped with work, but had a chance this last week to trouble shoot and tracked the issue down to the ignition....bad Dyna unit....new one on order and I should be good!

[Fergie]

Got the bike back from the mechanic today, and it runs superbly!

Anyone in the Northern Arizona area needs to check in with Curtis at Eurogeek...he knows his stuff and his rates are fair.

Here is the bike after the ride back to the office:


Thank you all very much for your help on this issue, I greatly appreciate it!

[850 Combat]

Thats fantastic.

All the wiring work you did may not have fixed cylinders 1 and 4, but it all needed to be done.

[renobruce]

Got the bike back from the mechanic today, and it runs superbly!

Anyone in the Northern Arizona area needs to check in with Curtis at Eurogeek...he knows his stuff and his rates are fair.

Here is the bike after the ride back to the office:


Thank you all very much for your help on this issue, I greatly appreciate it!

What exactly did your mechanic do?

[Fergie]

What exactly did your mechanic do?

He verified my thoughts and previous work!

I tracked the issue down to the ignition. While I was there one day, he verified this per the Dyna troubleshooting guide.

The pickup that controls the 1/4 cylinders was grounding out and not firing. I ordered a new Dyna and he replaced it.

I've put about 200 miles on the bike since thursday, and have had no issues!

Basically, I didn't have the time to work on the bike, but had the money to pay someone else to do it. I usually do my own work, but was tired of this one.