Tach and 2 cylinders dead when hot

[Sniffbooger]

I'm assuming I'm in the right forum...not sure, but I suspect I am experiencing an electrical issue...

My bike starts up, runs fine, been adjusting and synching the carbs periodically for the last couple months...

However, the last week and again today, when I commute to work, stop and go, my Vmax suddenly runs like crap, firing on only two cylinders I think, and the tach stops working! It drops to 0, the bike barely idles, and I'm sure its not firing on a couple cylinders. It seems to happen in the stop and go traffic, when the temp gauge goes up and the fan comes on.

First time it happened, I took the seat off, checked all the wires by the coils, and put it back together, it started and ran fine.

This morning, on the way to work, I just pulled over, wiggled all the wires by the left scoop where the Vmax controller and flasher unit are located, and turned the bike off. When I turned it back on, it ran fine.

Seems to cure the problem when I turn off the ignition, turn off the key, and re-start the motor, problem goes away.

Is this an overheating issue related to the TCI box under front of the airbox?

Any ideas and experiences are welcome!

Jacob

 

[Fire-medic]

I forget your bike year.

Sounds like the ignition is giving up the ghost. You could try re-soldering the board connections where the cable comes-in, sometimes that has helped people. Sean Morley has a set of electrical components, you pay for what you use. Replace one thing at a time. [email protected]

Adding your bike's year on the signature line helps us to answer your questions.

 

[Sniffbooger]

Ok, got the signature thing fixed... I have a 2000 Vmax.

So it sounds like the ignition is giving up the ghost??

That is not good... do you mean the TCI box up by the front coils is possibly the issue? This is the culprit that has the solder and bad connection issues?

The place where the cable comes in is where the connections are bad usually? I'm not too good at soldering....

I'll do some more reading...maybe I'll get an aftermarket one...any favorites??

 

[Sniffbooger]

I see a lot of people have the Ignitech unit...I'm leaning towards something more affordable.

I found the DB Electrical unit on Amazin for $150....anyone used one of these CDI units?

 

[Fire-medic]

Only 3 are familiar to me:

OEM (two types, '85--'89 and '90-'07)

Dyna (two types, '85--'89 and '90-'07)
Dyna has an older design and a newer design, besides the division above

Ignitech -contact Sean Morley about them, as he usually has them

I'm not familiar with the one you found. I've never heard of anyone on here using one. I'd stick with the three above.

Having the proper watts soldering iron for circuitboard work, and rosin-core solder should help you work better. Keep the tip clean and tinned.

Inside the ignition box case where the wires attach to the circuit board is where the re-soldering should be done. Look for dull joints, and even wire breaks.

 

[Jack Hammer]

Connect multimeter to your battery and let it idle until the fan kicks in. At least rule the option out that your voltage does not drop too much. At idle the alternator is unable to push to keep your voltage up.

Other than that, loose or bad connections and wires. I don't think the cdi is the culprit in this case.

 

[Sniffbooger]

Thanks for the input Jack Hammer....I'll get out the multi-meter this weekend...so far the fan comes on with no issues, and the battery is new, and I cleaned the ground wires to the frame last week...its just a random thing, the tach suddenly dies and its only running on two cylinders...it has been fine the last couple days...

 

[Jack Hammer]

What if you kept your average rpms up while riding? Will the problem go away? Carb sync done? No green on the copper wires just before crimped terminals? Think about the overall.

 

[Sniffbooger]

RPMs won't increase when this issue occurs, it wants to die and has no power...so I am forced to pull over and turn off the engine. Then when I turn the key back on, it goes away, starts and runs fine.

 

[Jack Hammer]

If you blip couple times while it occurs? Responds or not?

 

[Sniffbooger]

No, it won't respond it wants to die, missing on a couple cylinders with tach suddenly dead. Cannot raise RPMS when it happens.

 

[Jack Hammer]

So that tells me cdi thinks rpms are at one point, not going up. Pick up wire?

 

[pfeutim]

Hi all,

I have similar issues and it manifests in 3 to 4 problems:

1. sometimes RevMeter shows 5krpm instead approx the half (2,5krpm)
2. sometimes motor does nearly not react on throttle
3. sometimes motor shuts down on 1krpm
4. sometimes motor shuts down during driving (lets say at 3-4krpm)
5. Batt LoadVolt only 13,2 cold down to 12,8VDC hot
Resistance cold 100ohm / hot 128ohm (quite ok, but not exact what it should be)

What I checked/fixed/changed so far:

Batt Load Volt
-changed AC/DC converter - no changes, still bad VDC
-changed stator rotor (AC) and again a new AC/DC rectifier ->> this helped. Now 14.3VDC
-----> But none of the problems above disappeared.


Ignition
-new NGK Plugs, Connector and Cable (one cable was definitive too short)
-measured and inspected all coils, which seems to be "good enough" also slight higher in Ohm, but I think they should be fine. Also visually not cracks.


Fuel/Carbs
-new fuel filter -> ok before
-checked tank breathers -> ok before
-cleaned carbs -> ok before
-changed diaphragms on carbs -> ok before
-setup synchronization of carbs by light cap -> ok before


Solutions and Plans:
-during the driving I thought I have to stop the engine and restart, to get all immediate back to normal
- after a while I found out, that by clutching and waiting until Rev goes down to 1krpm, this does a "Count" Reset and everything work like a beast until next hick-ups

Next open task
-I'm still waiting to the PickUp Sensor I did order, so I can not report yet, if this is my problem

-If the pickup is not resolving all problems above, I have to invest on a Ignition Module CDI
---->here I would very, very appreciate all your experience made with the different types.


Many thanks

 

[Sniffbooger]

In reply to your earlier posts Jack Hammer,

Yes, I have synched the carbs good, whenever I remove them and replace them the last couple months. This is an intermittent and random issue I am having, and I am sure it is an electrical issue, not a carb issue.

I have also clipped and cleaned the ends of the spark wires near the coils on the rear ones under the seat, cleaned the connectors there, and even noticed some cracks on the bottom of the coil casings. I've read here it would be ok to silicone the cracks if the coils check out ok....I haven't checked them yet with a meter, and I haven't inspected the front ones either because they are buried under the front of the frame and I can't reach them very good. I got a hand on one of them, but the cap is twisted on so tight I can't remove it. So that's a project for another day.

If I blip the throttle when the issue occurs, it doesn't want to rev because its only 2 cylinders and doesn't want to pick up...the tach is dead when the issue occurs and doesn't show any RPMs at all...but I can tell its not revving much when I blip it, just trying to keep it running so I can get off the road...

A few weeks ago I reconnected the wire that I believe is the pickup wire at the connector under the seat, right side, because it was frayed at the connector. I'll check it again this weekend.

 

[Jack Hammer]

Cracks on coil casings sounds like they have been running too hot. That might manifest what you are experiencing. Just throwing ideas.

 

[Jack Hammer]

Pfeutim, you seem to have one common problem with Sniffbooger that strikes me weird. Erratic read on the tach. This would take me to look at the pick up too.

Such problems are not related to the cdi itself, maximum the pin connection on it. Let the bike run and take the cdi in your hand, shake it and twist the wiring and see if your problem occurs. Electrical components are usually a one shot deal, first they work and then they die. They don't come back. This really sounds like a connection issue, like a loose pin or bad wire.

 

[Sniffbooger]

Rode it 18 miles to work this morning, in stop and go traffic, the temp gauge went up til the fan came on many times, no issues today...this is an intermittent and random issue...not even sure its heat related at this point...I'll spend some time this weekend checking wires and connections and coils...

 

[pfeutim]

Pfeutim, you seem to have one common problem with Sniffbooger that strikes me weird. Erratic read on the tach. This would take me to look at the pick up too.

Such problems are not related to the cdi itself, maximum the pin connection on it. Let the bike run and take the cdi in your hand, shake it and twist the wiring and see if your problem occurs. Electrical components are usually a one shot deal, first they work and then they die. They don't come back. This really sounds like a connection issue, like a loose pin or bad wire.

Hi Jack,
many thanks for your lines.
I fact I'm waiting to the pick up sensor arriving.
What I additionally did and not wrote above is, that I cleaned all dozens of connectors with spray and connected back 2-3 times to remove any oxidation.
The connector of the pick up I even made new, as my fear is there.

Also I can say, that my problem started slowly and is getting worse over a month now. Firstly the vmax pushes/pulls just a little bit in the partial load range. Then it start with pretty hard and short power holes and now I'm on the stage, that the bike even stops or does hardly react on the throttle.

The thing I wonder really is, most of the cases when this happends, I only have to press the clutch, wait until I'm on 1krpm then everything works again for a while. This leads to me to a chaos in the Cdi (possibly and hopefully comming from the pick up miss signaling)

 

[Fire-medic]

My experience with a couple of bad pick-ups is that the bike would start and run fine, but after maybe 20 minutes, it would cut-out entirely (the engine would suddenly die) and the starter would spin but the engine would not re-start. Let it cool-down, and it would start fine and run for a similar period then die. A new pick-up fixed it both times. I have the 2-wire pick-up, so a broken wire went open (not conducting) on one wire or the other.

Another time, it was the ignition box. I bought a DYNA to replace the OEM and it's given me no issues since. Twenty-nine years of owning various VMaxes from 1985 build dates to 2005 build date, so both old 5-wire ignition systems ('85-'89) and the 1990+ 2-wire ignition system.

Anyone following this I think CaptainKyle has an early 5-wire DYNA ignition box for sale, if he hasn't sold it yet. That would be a good back-up.

 

[Jack Hammer]

Just like with old Mopar muscle cars with stock type electronic ignition, always keep a spare box with you.