RGS Ignition / Electrical problem....where is Nikola Tesla

henrywillms

henrywillms

Hero member
Location
Canada
I have problem with my RGS I am trying to diagnose, with no luck so far. Looking for some ideas in hope of identifying the problem in the next couple of weeks before winter sets in and I can't do any test riding.

Motorcycle:
RGS with Witt 2 ignition/ optical sensor
Modern coils...from Wolfgang...forget the brand, probably 10 or 15 years old
Other changes to stock wiring:
Alternator phase that ran to headlight switch now plugged directly to Regulator/Rectifier
headlight relays running from fuse box to headlights, trigger to relays via factory wiring/switch
Volt meter wired via a relay to battery and switched from taillight power wire (headlight switch can turn it on off)

Problem:
WITH HEADLIGHT ON: When accelerating hard, such as coming out of a corner in a low gear at low RPMs and reving up to from low rpm thru and up to higher RPMs the ignition appears to be intermittently cutting out several times thru this acceleration. Bike still reaches high RPM but you can hear it cutting out and in. It feels much like when a spark plug cap contact to sparkplug plug terminal is worn and vibration causes a misfire. This misfire occurs every time it's under hard acceleration but intermittently throughout the acceleration period. It stops as soon as you stop accelerating and reach a constant RPM...typically in the 3500 to 5000 RPM range for me.
It does not happen at constant speeds or when accelerating slowly or only increasing RPMs by couple of thousand RPMs.

WITH HEADLIGHT OFF: Bike runs perfect. No misfire/cutting in and out under any conditions. As soon as you turn the headlight off the problem goes away, even when you turn it off during the time I am accelerating hard and its misfiring. If I turn headlight back on the problem starts immediately.

The bike had been running fine and I made no changes to the bike. I thought there maybe problem a month or two ago in my normal riding in the flatland straight roads where I live. But I really only ride it hard when I am passing someone on the hiway, ie going from 90kph to 130kph. In this scenario it is mildly noticable. When I spent a few days riding the twisty, hilly Wisconson back roads the problem was there accelerating out of every corner.....but it sure was fun so I just rode with headlight off.

Diagnosis and changes so far:

I thought it may be a lack of voltage/amps to the ignition based on headlight off, there I'd no problem
Replaced the battery. Old battery (Odyssey PC680) tested ok ( volts 12.2 and load test showed maybe a bit weak ) and it was 11 years old.
New Odyssey is PC680 equivalent
My voltage at highway speeds (4000 rpm range) is 14.2 to 14.5 with headlight off, and 13.5 with headlight on. Voltage can get a bit lower in city driving, say 13.2 but I almost never ride in the city
Alternator phase test, alternator wires unplugged from regulator, measure A/C .....voltage rides to 80 at about 5000 RPM or so

Wiring and connections
Visually checked most of the connections on the bike for corrosion and contact. Battery, grounds, alternator to regulator, Witt multi pin and at coils, to optical sensor, ground and power.. Multi pin connectors and bullet connections under gas tank, close to coils. Fuse box terminals and wires. All were clean and tight
Didnt check ignition switch, other switches or at guages. Didnt use multimeter to check for voltage drops except at headlight and it was good. Didnt test coils...just realized I probably should have.

Spark plugs and caps have maybe 2000 km of use. Replaced late last summer. NGK 5000 ohm resistor caps are tight fit and and have correct resistence. Plugs are non resistor Champion N3C. Visually look like they are running good, though I know a visual check is not that accurate with modern fuels etc,
Have not tried new plugs or caps given they are almost new.

Checked the Witt optical sensor visually to make sure it was clean ....it appears clean but blew compressed air at it anyway.

Now what?

None of the above found or the fixed the problem.

It seems to me it's either a faulty connection, either vibration or resistance related, that the increased 12v DC power with the headlight turned off can overcome. Or a lack of enough DC power for the ignition system, or a faulty Witt box; again when the headlight is off the problem is overcome by increased DC power.

A loaner Witt box would eliminate a lot of searching if that's that is the problem. Are they prone to this sort of problem?
It sounds unlikely it's a charging problem unless the regulator can fail one one incoming phase so it is not producing enough of a charge? Any way to test that? Or just replace it....its original.
I will test the coils but I dont expect to find anything...with my limited understanding anyway
I can try news caps and plugs....just in case.
Look for a poor wiring connection...like a needle in the haystack.

Gentlemen????
 
Every problem I have ever had with a Witt ignition has been from the regulator. My RGS drove me crazy to the point of never wanting to ride the bike again due to this. The regulator Laverda used can do all kinds of bad things when they get old. Get one from a JAP bike. Shindengen is the best.

My RGS regulator would always test good at home, but miles away from home it would be evil.
 
Is the misfire across all three cylinders, or is it just one?
I had an intermittent misfire on my RGS across all three cylinders, just like flicking the kill switch very quickly Off then On.
After much head scratching and trial & error, the issue turned out to be with the sub-loom for the Witt ignition - that's the big plug that connects to the box and the associated wiring that comes with it, specifically a break in the Live feed.
A new sub-loom from Uwe Witt (€20 I recall) and the problem was resolved.

Good luck 🤞
 
Could the contacts in one of your relays be flickering/bouncing when you are accelerating, and you are only noticing it with the extra load of the headlight. ?
 
I agree with 1200TS, seems like quite a bit of variance in voltage from the regulator, although I’m not sure what the old ones tolerances were or how sensitive Witt’s are? My new Shindengen varies about 0.2v. Replacing yours wouldn’t hurt and it’ll probably make your nice new battery last even longer 👍
 
Electronic ignitions can fail in strange ways. If you can borrow another Witt ignition for a 120 triple, it would be interesting to see if it cures the problem.

Bike power systems are not characterised by a smooth DC voltage supply. There are all sorts of spurious voltage dips, rises and spikes that can play havoc with sensitive electronic components. It wouldn't surprise me if some power spikes or a particular frequency in your bike's electrical system is upsetting the Witt box.

I had an early blue box Witt ignition that would throw a fit occasionally. I never figured out what triggered it, but it reminded me of the BBC sitcom "The IT Crowd" because I had to turn it off and on again to re-boot it (an IT Crowd catch phrase). After re-booting, it would run again until the next time it threw a wobbly. At first it was just an infrequent anomaly, but it gradually started doing it more and more often until it became a bloody annoyance and downright dangerous. When it cut out as I was turning across an intersection in the path of an oncoming car, I figured I'd had enough.

Another nail in the Witt's coffin was that it became quite sensitive to voltage. It only worked within a narrow band that got narrower as the thing got older. It would start to miss if the voltage got above about 13V. Even after fitting a voltage limiting resistor to its power feed, I had to run with the headlight on to stop the voltage getting too high.

I suspect Uwe Witt has improved his ignitions since that early version, but I had lost confidence in the product so I replaced it with an Ignitech.
 
As it only appears when lights are on, it must have to do with the 3rd phase of the alternator coming into play (The wiring of that phase is routed through the headlight-switch on the RGx type 120° triples). Either the voltage gets to high (due to the 3rd phase) or to low (due to the lights cutting in). How have you wired the plus of the DMC? Via the ignition key, with a relay or without, please? If with a relay, remove the relay. We had that before, does not work properly for what reasons ever.

First test: remove the plug from the H4 bulb and test again, switching the light switch on. If problem persists, it's either to high voltage or a contact issue in the switch; If the problem is gone, it's to low voltage and you might have a contact problem at the H4 bulb connector or the 9-Pin connector on the right side of the frame. If possible, put a volt-meter on and connect it to the headlight bulb connector and check voltage when this happens.

Next test: change the switch-cluster on the handle bar against a different one

please report back once you've done that. Interesting problem that is...
 
Guys....thanks for replies so far. I am away from the bike right now but hope to get back to it in the next few days and follow up on your suggestions.
 
After some more inspection, swapping out parts and several test rides I seemed to have solved the problem(s). I'll tell you the whole story so you can experience for yourself the lows and highs of my journey in Laverda motorcycle ownership.

In my initial post, above, I had checked and tested and cleaned up a few things, with no difference. Ignition still sputtering while accelerating hard in the 4000 to 5000 rpm range with the headlight on, but ran perfect with headlight off. And charging voltage seemed low under load from the headlight.

In this go around I checked the coils for resistance. They were good, so while I was waiting for a test Witt box and a voltage regulator I changed the spark plug caps (even though the ones installed were almost new and tested good) and the sparkplugs plugs "just in case". I went for a test ride and it seemed the problem was less pronounced but still there. I was low on gas so I filled it up and set off for some more seat of the pants testing. I got a few blocks from the gas station and all of a sudden the bike seem to be running real bad.....I checked to make sure I had turned the petcocks back on....and I had....you all probably thought I had fucked this up didn't you! It felt like it was running in two cylinders.

Back in the garage I check the exhaust temps with my infra red tester and the left cylinder is a lot cooler than the other two. I discover one of the 14 guage wire spade connectors to the coil is actually broken right apart. I suspected and hoping it must have been broken before or almost broken but the plastic cover was holding it together, and this was my ignition problem all along. I had these wires on and off a few times looking for problems and I guess the last time I put it back on it finally completely came apart and the engine vibrations caused it to fall off. I replace the connector and off again for more testing.

So now, obviously, the last problem when the left cylinder cut out completely is resolved, but also the ignition cutting out is not happeing as bad or as often it was before. But there is still something going on some of the time....a bit of a stumble, cut out and short delay sometimes.... with the headlight on, never with headlight off.

I get another Witt box and regulator to try. One change at a time. First I swap out the Witt box. Immediately the ignition problem goes away...with headlight on no burps, farts or stumbles under any conditions. This is the first time there has not been any issue with the ignition since I started resolving the problem. So I conclude three things... my Witt box is no good, the broken connector was causing an intermittent problem before it completely broke away and lastly IF I have a charging problem it shouldn't be affecting the ignition.

Next the regulator......a factory one same as my RGS came with. This immediately changes my charging voltage. With my original one it was charging at 14.2 to 14.5 on the highway with headlight off, but only at 13.5 with headlight on. At slower speeds it might be 13.2. The new one is at 14.5 with headlight off and 14.2 with headlight on, at all RPMs. So now I know I had a charging problem and replacing the regulator will fix it.

So now I decide to put my "not so good" Witt box back in with the new regulator. There is still an ignition problem with headlight on but now it seems even subtler with the new regulator.....less stumble and less often. The only other variable is it's much colder outside in this round of testing.....10 Celsius.

A few days later it gets up to 7 Celsius and I try another test ride, "not so good Witt box" and the good regulator. I have a hard time discerning there is an ignition problem at all. This ride was shorter than any other test rides but I dont know if ambient temperature or a longer ride affects whatever problem the Witt box may have. I got to think the Witt is no good but this last ride is the only time the ignition problem didnt manifest itself (AND I DIDNT CHANGE ANYTHING from the previous rest run!). Temps around the freezing mark so I now have to wait to spring if I want to test it some more.

Right now it seems highly likely I have a Witt problem, I am tired of testing and I dont want a problem if I'm on a long trip far from home So I may change the Witt box even with this last test not showing a problem or I could wait to spring and try some more test rides. I have 5 months of winter to think about it.

Oh...... and on the last test ride and some car in front if me sent a small rock or piece of gravel up into my fairing and chipped the paint.....and with my luck.....hopefully this does not cause an ignition problem!!!!
 
The new replacement regulator you received, throw it as far away as you can. It is 40 years old and will most likely eventually cause problems just like the old one. Get one off a Jap bike. Shindengen is the best. As I stated in my post before, the Witt ignition is very sensitive to over voltage conditions. My factory regulator would work perfectly for about 10 minutes and as it warmed up the voltage would go to 15 volts and the bike would run bad and the Witt ignition would shut off.

We need John Wilson back making ignitions. They always work perfectly and don't care what voltage they see.
 
Isn't electrickery a wonderful thing! :eek: Good on you for going through the process of elim and tracing not one, but THREE faults (reg, Witt and spade terminal). Once you find the cause everything seems so bloody simple!
 
Yes I will get a modern regulator. The one I got was just for testing. But after 40 years it still worked as it should unlike mine.
 
"working" is a relative term, Bruce has the experience on Witts and RR to be a first person to take advice from. Not a lot new in actual hardware faults these days, henrywillms all the processes ( to locate faults ) you performed have been known for many decades. Firing of ignition system without the motor running was a feature in the iis, you could then shake the connections and parts on the ignition system without risking your life on the open road looking for what can be dangerous procedures. Would imagine Ignitech has this feature also.

Can be very personally depleting, chasing intermittent electrical faults or combination of faults ( the latter you have engaged upon ), always, easy things first, then break the circuits into sections for narrowing down of likely fault or faults.

Begs the question why persist with the Witt DMC, while served a purpose and market gap ( was before the iis ) it is of an era and with known peculiar issues, resolved with later production or no. HTH j
 
You must log in or register to reply here.
Back
Top