Absolute Head Scratcher.
- Thread starter Vince
- Start date
3CBRG
Senior member
- Location
- Northern California
A multimeter at this point would be handy.
Dellortoman
Hero member
- Location
- Tasmania, Australia
You could be right about that being a clue, and a pretty damn good one.
The starter button and kill switch are located closely together in the same housing in the right hand switch block, and I'm reasonably sure they share a brass contact strip (although it's been a long time since I had one apart so my memory could be a bit hazy on the physical configuration of the switches). Anyway, I'm guessing that there may be an unreliable connection at the kill switch contacts that causes an occasional disconnect, thereby shutting off the ignition and killing the engine. Could be a bit of dirt or corrosion on the brass contacts.
An attempt to clutch start using the momentum of the bike would fail unless the kill switch contact is re-established.
However, pressing the starter button might give that lump of brass enough of a jiggle to re-connect the kill switch so the engine starts again.
Schematic wiring diagram of the right hand switch block that illustrates what I'm talking about. Take it apart and clean any dirt and corrosion off the contacts.
CRC 2-26, highly recommended to you Vince, many the problem overcome with a short spray. Some contacts will degrade in time and require regular spraying if not outright replacement, there were some nice switch blocks around at the wreckers, more modern and very good "feel" under thumb, Aprilla for one have used.
Cam, has the notion of a mechanical issue looking like an electrical issue, one of the more obscure problems in electrical and electronic diagnosis, The ND switch blocks are very reliable, though not maintenance free as such. HTH j.
Cam, has the notion of a mechanical issue looking like an electrical issue, one of the more obscure problems in electrical and electronic diagnosis, The ND switch blocks are very reliable, though not maintenance free as such. HTH j.
Tippie
Hero member
- Location
- Dr?bak, Norway
This stuff is magic
I have Deoxit 5 in a press spray, no propellant so it is sendable in normal post.
DeoxIT D-Series page with shop - CAIG
DeoxIT® D-Series contact cleaner dissolves oxides and sulfides that form on metal surfaces. This restores the contact’s integrity and leaves a thin microscopic layer that protects the metal. Special additives improve conductivity and prevent dissolved oxides from re-attaching, keeping them in...
caig.com
breganzane
Hero member
- Location
- NSW Australia
Cam could be onto something. When I rebuilt my 79 Jota in 2016 (good grief!) it had never skipped a beat in the ~16 years I'd been riding it 'unrestored' after buying it as a neglected and crashed bike, only having given it basic repairs and maintenance.
When I pulled apart the switches this was the state of the kill switch wiring:
It had just one strand of wire left, hanging on for grim death patiently waiting for restoration. I think I maxxed that one out! NOS blocks were available back then, so I fitted a new one, although scuffed up the new two-cable bottom half casting while reusing the old bashed top half in order to match the rest of the bike!
If it's not that then the ignitech plug contacts are the most likely. They require a very particular type of crimper which creates unusually tall and narrow terminal crimps, and can only take a moderate wire size. Attempts to use 'normal' flat/wide crimpers and/or oversize wire or multiple conductors can be problematic.
When I pulled apart the switches this was the state of the kill switch wiring:
It had just one strand of wire left, hanging on for grim death patiently waiting for restoration. I think I maxxed that one out! NOS blocks were available back then, so I fitted a new one, although scuffed up the new two-cable bottom half casting while reusing the old bashed top half in order to match the rest of the bike!
If it's not that then the ignitech plug contacts are the most likely. They require a very particular type of crimper which creates unusually tall and narrow terminal crimps, and can only take a moderate wire size. Attempts to use 'normal' flat/wide crimpers and/or oversize wire or multiple conductors can be problematic.
Good pic Steve, well worth a look, but not in today's 40c heat. I well remember Christian letting us do an Ignition bypass hotwire job at your place on my bike, heading home from a Tassie trip, after we later discovered that my main ignition earth wire had stretched and snapped 50mm up under the insulation, when my battery strap had snapped after a small tipover. I guess if you do the ks, shit happens and breaks. I think this is the 4th or 5th oddball ignition issue in the last 35 years with Boshe, Wilson, and now Ingatch Ignitions. So I have had nuts come off connections, keyed switches fail internally, wires break, batteries lose cells, wires get cut on Altinators, coils lose earths, plugs fail, the best example of a plug fail was having a chunk of piston brake off and hit the spark plug and close its gap, would you class that as an electrical fault? I think that's the lot over the years.
Tippie
Hero member
- Location
- Dr?bak, Norway
It was standard to say it fouled a plug on GP two strokes, cause being a melted or smashed piston. Never admit a blown engine.
chrisk
Hero member
- Location
- Brisbane, Australia
Should the said syndicate win, Vince would probably breakdown on the way to pick up the winnings.It’s fair to say that i would not be going into lottery syndicate with Vince based on that last post
Tom
Reading all of this I would guess at a possible earth problem.
Reasoning as follows.
Engine cuts intermittently,
will not restart even high speed "bump" until you press the starter button and then it starts instantly.
By pressing the starter you are pulling heavy amps through the earth, enough to over ride and problem that would cause a low power draw to hickup.
It's about the only thing I can think of that would allow you to start on the button while not with a bump.
Has to be something like the starter draw giving the electric system a kick up the backside.
Good luck, very interesting problem,
Sorry it's so irritating for you,
J
Reasoning as follows.
Engine cuts intermittently,
will not restart even high speed "bump" until you press the starter button and then it starts instantly.
By pressing the starter you are pulling heavy amps through the earth, enough to over ride and problem that would cause a low power draw to hickup.
It's about the only thing I can think of that would allow you to start on the button while not with a bump.
Has to be something like the starter draw giving the electric system a kick up the backside.
Good luck, very interesting problem,
Sorry it's so irritating for you,
J
I have a can of CRC Contact Cleaner, and I expected CRC 2-26 to be the same stuff, but Google enlightened me. CRC 2-26 is a contact cleaner that also adds a corrosion inhibitor to electrical contacts so they don't start corroding immediately after they get cleaned. Really important on bikes ridden in all weathers. So much for my old, obsolete can.
You are correct to have both the CRC CO cleaner AND the CRC 2-26 Vince, no error on your part. CO will strip every last vestige of oil in rotating or moving parts like switches. It will "dissolve" contamination as a guide, though cleaned contacts are prone to contaminate sooner than later. The CRC 2-26 will dissolve most contamination ( remove the unwanted corrosion ) and provide a lube, with protective film of sorts, it will also dissipate in time. If you must, CO first then a few minutes later 2-26 ( not the promoted 5-56, the MSDS shows different composition ), i purchase both tins in 5-10 trade lots here.
One aspect of the 2-26 is that the propellant exhausts before the active chemical is used, myriad of tins here with stab holes in them to use up the last of the active ingredients, HTH j
One aspect of the 2-26 is that the propellant exhausts before the active chemical is used, myriad of tins here with stab holes in them to use up the last of the active ingredients, HTH j
So, finally managed to dodge some crazy weather, 45 °C on 2 separate occasions requiring date changes, and I managed to trailered my 3c to Laverda Guru Central for 2 very needed inspections. A valve clearance check, the main reason why the bike was tailered out. Dead cold engine for the valve check, we had a discussion about how many years and ks since Red did my head and engine rebuild. I thought at least 2 Tassie trips and maybe 10 Snowy Runs MAYBE. Anyway, no shim change required again. Inpressive concidering how that bike gets a flogging. And the mysterious engine cutting out randomly. Firstly, no issues were found with the kill switch block, but it was given a good internal clean. The earth to the ignition was routed oddly and had some twisting at its connection plug, and one of the pins in the connection block came adrift with barely any pressure, so the plug was depinned and redone. So, nothing absolute like a smoking gun, but enough to suggest some voltage drop in the wiring to the system. Got some rides coming up, so that will indicate if its competely sorted. I am really looking forward to getting back into those upcoming club rides. We do have some great brother riders in Laverda Land. Thank you to the Guru for imparting his considerable abilities in these fields.
I mentioned on another thread. I had similar issues last summer...Red advised likely the regulator..changed..fixed. nearly killed me cutting out in the motorway fast lane..just like turning the ignition off...coasting to hard shoulder across 4 lanes of traffic!! Then started on button....am running Sachse sourced from Red years ago, non optical pick ups.
It gets your attention; a couple of my episodes happened in the fast lane passing trucks. NOT FUN. I live just off the expressway north of the Sydney Harbour Bridge, with no breakdown lane on the bridge. In the end of that long day, the last 3 hrs went with zero issues, must have been a bodgy connection, hopefully fixed now.