G
Geezer
Guest
A newby question. I wondered which electrical parts I need for the rebuild of my 1000 3C 1974 with Bosch ignition. Off course I need a starterrelay but what parts do I need more???
R
Reggie3cl
Guest
'pends wots broke really. I threw away (and replaced 
) the starter relay, most of the wiring, switches, the charging system, coils and ignition on my old bike, others run their bikes mostly stock.
Having said that, a Saches (sp?) or Witt ignition is always money well spent.
) the starter relay, most of the wiring, switches, the charging system, coils and ignition on my old bike, others run their bikes mostly stock.Having said that, a Saches (sp?) or Witt ignition is always money well spent.
mcnicol
Hero member
- Location
- Safety Harbor, Florida, USA
Geezer
If you have the original ignition you have a Bosch HKZ system, which was state-of-the-art in it's day but alas is no longer particularly remarkable. The good things about it are the pickups are pretty indestructible but the wires from the pickups do need insulation replaced, you can do it yourself if you're careful or have an automotive electrician do it. If your old wiring loom is OK use it, although you might want to think about moving the junction box for the ignition/power up to the back of the tank and away from the spray area in front of the back wheel.
The CDI box under the tank either works or it doesn't. When they work they're OK but not really up to keeping a strong spark at high revs. When they don't work you have to buy another 35 year old one secondhand. and you only have 1 advance "curve" which is pretty aggressive, designed for racing where you don't need anything except full advance much.
Lighting power is also a major issue on the HKZ systems, you may have as much as much as 120W if you're lucky, but this is at 7500 rpm, no regulator. If you use it around town get used to push starting with a flat battery. I was good at it when I was 20, at ... well, more than 20, I don't think it would be much fun anymore.
All these problems can be addressed with the installation of a modern digital ignition. You have several choices, a German one from Uwe Witt, an Australian one from John Wilson (saw a used one just the other week, but he doesn't actually make them any more and this may not be a good lead), another German one from Sachse, and (iirc) a Czech one from IgniTech. All good, all address the power issue differently. Redax Engineering in Australia do a complete stator and flywheel with a much larger alternator, the Witt one supplies a higher output charging coil. Lots of threads about these things in the archives here. All provide much better ignition and a choice of advance curves, necessary with the modern fuels we have to use. You'll have to replace the coils too, recommendations vary depending on the type of ignition you install.
Aside from that decision, the rest of what you need is just determined by fixing what previous owners have done to the bike over the years. For an Italian bike, Laverda actually did a pretty good job of designing and installing the components, just matching original specs should be enough. Use quality connectors (a bit hard to find) and match the original wiring gauges. You'll probably find handlebar switches are pretty badly worn, you can still get original NipponDenso switches if you look around, but they often clean up fairly well with a bit of TLC.
Ken
If you have the original ignition you have a Bosch HKZ system, which was state-of-the-art in it's day but alas is no longer particularly remarkable. The good things about it are the pickups are pretty indestructible but the wires from the pickups do need insulation replaced, you can do it yourself if you're careful or have an automotive electrician do it. If your old wiring loom is OK use it, although you might want to think about moving the junction box for the ignition/power up to the back of the tank and away from the spray area in front of the back wheel.
The CDI box under the tank either works or it doesn't. When they work they're OK but not really up to keeping a strong spark at high revs. When they don't work you have to buy another 35 year old one secondhand. and you only have 1 advance "curve" which is pretty aggressive, designed for racing where you don't need anything except full advance much.
Lighting power is also a major issue on the HKZ systems, you may have as much as much as 120W if you're lucky, but this is at 7500 rpm, no regulator. If you use it around town get used to push starting with a flat battery. I was good at it when I was 20, at ... well, more than 20, I don't think it would be much fun anymore.
All these problems can be addressed with the installation of a modern digital ignition. You have several choices, a German one from Uwe Witt, an Australian one from John Wilson (saw a used one just the other week, but he doesn't actually make them any more and this may not be a good lead), another German one from Sachse, and (iirc) a Czech one from IgniTech. All good, all address the power issue differently. Redax Engineering in Australia do a complete stator and flywheel with a much larger alternator, the Witt one supplies a higher output charging coil. Lots of threads about these things in the archives here. All provide much better ignition and a choice of advance curves, necessary with the modern fuels we have to use. You'll have to replace the coils too, recommendations vary depending on the type of ignition you install.
Aside from that decision, the rest of what you need is just determined by fixing what previous owners have done to the bike over the years. For an Italian bike, Laverda actually did a pretty good job of designing and installing the components, just matching original specs should be enough. Use quality connectors (a bit hard to find) and match the original wiring gauges. You'll probably find handlebar switches are pretty badly worn, you can still get original NipponDenso switches if you look around, but they often clean up fairly well with a bit of TLC.
Ken
troutbishop
Hero member
- Location
- Worcestershire England
Hi Geezer i am building a 74 3c from scratch myself what bits do you already have or is it a start from nothing job ?
Kev
Kev
Cosi
Hero member
- Location
- Kingscliff
Throw it away and get a sachse or witt, your just wasting money on old shit and youll end up replacing it eventually with one anyway, save the headaches 
Sorry i should rephrase that, replace it, dont throw it, apparently their gonna be worth heaps oneday
Sorry i should rephrase that, replace it, dont throw it, apparently their gonna be worth heaps oneday
G
Geezer
Guest
Thanks for youre advises. Its a project someone started, bought several new things and then left everything in the corner of his garage. So now I will finish the project. There's a complete new wire-loom and some relays etc. I think I need a starter relay, a voltage rectifier (or whats its called? ) and a diode??? I have the Bosch ignition box which I will first try, because the previous owner told me this was a new old stock piece. I desperate need a good highly detailed wiring diagram, is there something to find on the web? Btw, it seems a lot of 3C's still using the Bosch stock ignition, so first I will have it a try, after all an new electronic system hits my budget very badly I think.
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3patC
Guest
Hello Geezer, I am in the same situation as you, I bought a bike with absolutely no wiring but fortunately I used to own a similar 3C so I had some idea of what was required. I bought a new loom but even after that I realised there were a lot of periphery wiring looms and connectors required but luckily a complete original wiring harness with all the extra parts came up on ebay and I bought it so if you look at ebay item no 130511640477 you will see virtually everything you need. The green book has the wiring diagram you require. If you need any further help let me know Regards Pat
R
Reggie3cl
Guest
As standard (IIRC) there is just a small 'snuff box' sized rectifier and no regulator. I think one of the coils on the ignition plate is wired up to sort of counteract the other two to keep the voltage down*. If you're not changing to a Witt then it might be an idea to use a modern (Electrex?) regulator/rectifier and wire up the third coil to boost your charging system. And use an Odyssey battery.
There is a diode in the headlight to prevent the parking light being switched on when the ignition is off.
*This may be complete cock, no doubt someone with some proper knowledge will correct me
There is a diode in the headlight to prevent the parking light being switched on when the ignition is off.
*This may be complete cock, no doubt someone with some proper knowledge will correct me
mauricejota7604
Hero member
- Location
- Victoria Australia
Hi Geezer I am also building a 3C from scratch and bought a new wiring loom that suits later 3CLs/Jota with multi plug connectors the original 3Cs had 2 banks of connectors in the headlamp with female mulitple spades a nightmare with wire congestion according to others.
The ND multi plug connectors connect outside the headlight and are very reliable.
I guess since you have a "NOS" Bosch CDI ignition you are morally obliged to try it and who knows it may be OK I was also considering using the one that came with my bike, but considering as Ken mentioned the poor advance setup adds unnecessary stress to an old engine and I want to be able to do 1000km days on mine I chose to buy a Redax Sachse complete with Alternator upgrade, reliable choice of advance curves and no battery going flat.
Have a think about it.
M.
The ND multi plug connectors connect outside the headlight and are very reliable.
I guess since you have a "NOS" Bosch CDI ignition you are morally obliged to try it and who knows it may be OK I was also considering using the one that came with my bike, but considering as Ken mentioned the poor advance setup adds unnecessary stress to an old engine and I want to be able to do 1000km days on mine I chose to buy a Redax Sachse complete with Alternator upgrade, reliable choice of advance curves and no battery going flat.
Have a think about it.
M.
CLEMTOG
Hero member
Dickie non jock,
I think you are getting confused a bit,the first triples had no regulator at all, and a self generating ignition system, with pathetic battery chargeing (Bosch generator/CDI)
the slightly later triples had batterypowered ignition, and a rectifier/regulator, the chargeing system was a little better (Bosch generator/BTZ)
later 180 types and all 120 types all had even better generators (Nippon Denso) which caused the ignition pick ups to be moved to the left of the motor, but still Bosch BTZ type either two or three pickups, this type has seperate switching to bring in an extra generating coil only when the headlight was turned on (ND generator/BTZ)
With DPO syndrome it could be very easy to get a mis match of non compatible components.
CLEM
I think you are getting confused a bit,the first triples had no regulator at all, and a self generating ignition system, with pathetic battery chargeing (Bosch generator/CDI)
the slightly later triples had batterypowered ignition, and a rectifier/regulator, the chargeing system was a little better (Bosch generator/BTZ)
later 180 types and all 120 types all had even better generators (Nippon Denso) which caused the ignition pick ups to be moved to the left of the motor, but still Bosch BTZ type either two or three pickups, this type has seperate switching to bring in an extra generating coil only when the headlight was turned on (ND generator/BTZ)
With DPO syndrome it could be very easy to get a mis match of non compatible components.
CLEM
R
Reggie3cl
Guest
I'm old, my memory grows dim... So what would my 1977 180 have had- there wasn't a regulator that I remember, just the wee snuff box under the tool tray. Surely that wasn't a reg/rec was it?
mcnicol
Hero member
- Location
- Safety Harbor, Florida, USA
mauricejota7604 said:
I rather suspect that the reason so few early 3cs are left is that once the wires were pulled out of the connectors in the headlight NOBODY was able to put them back, so the bikes quietly rusted away in the backs of sheds. Wires entered the connection blocks one colour and emerged a different colour on the other side, and there always seemed to be a lot more wires inside the headlight than there were circuits. Every time I reached the limit of my abilities with electrical stuff and had to go to an automotive electrician I was told never to bring it back until it was rewired properly.
Fortunately the only major problems I had were the CDI box under the tank dying (I replaced mine twice), and the woefully inadequate charging circuit. Mine was a very early model with a single 100W charging coil. Oh, and my rectifier died, I gutted the little cast box and rebuilt it with epoxy and automotive diodes, and I think it actually worked better after that (less power loss).
I do have a detailed circuit diagram on a USB drive somewhere, as soon as I find it I'll post it.
Ken
D
Davo
Guest
mauricejota7604 said:
So did the early 3CLs. I can vouch for that. Not just a huge jumble of wires but could be bloody difficult getting the headlight back together. I often worried about the lens popping out while I was riding it considering it was only held against the pressure of all those wires by a spring clip.
mcnicol
Hero member
- Location
- Safety Harbor, Florida, USA
Davo
Yeah, at least mine had the 200 mm ex-army searchlight headlight bucket, and even so it was tight fit. But at least mine had a decent screw at the bottom, and if I coiled it to just the right diameter I could get a spare clutch cable in there, and it stayed mostly dry. Just as well, I needed it fairly often.
Ken
Yeah, at least mine had the 200 mm ex-army searchlight headlight bucket, and even so it was tight fit. But at least mine had a decent screw at the bottom, and if I coiled it to just the right diameter I could get a spare clutch cable in there, and it stayed mostly dry. Just as well, I needed it fairly often.
Ken
When I first got my 3C I noticed a few slightly melted wires in the birdsnest headlight,so I dragged out the green book and started chasing wires following the diagram and cut out the damaged bits.I start connecting it back and buggar me its smoking and melting again.I recheck and recheck till the little light goes on.I was one wiring diagram off and they had changed wire colours between years,not small changes but big dead short type changes and the DPO had made exactly the same mistake,bloody chocolate block.There was 2 of them in my loom,1 in the headlight and 1 on the frame behind the petrol tank.The best thing I ever did was get the mysterious Phil The Wire to completely rewire it,10 years of DPO wiring bodges are not good for the heart
Dellortoman
Hero member
- Location
- Tasmania, Australia
As a general rule on any old bikes, and especially Italian ones - Never trust the wire colours.
Italian manufacturers seem to be a bit casual about matching the colours to the diagram, or even matching them to the other wires in the bike. Many times I've seen a wire change colour as it goes through a connector block. You never know what previous owners may have done either.
Whenever I disconnect wires and it's not obvious where they go, I draw myself a little diagram so I don't get it wrong when it comes to reassembly.
Cheers,
Cam
Italian manufacturers seem to be a bit casual about matching the colours to the diagram, or even matching them to the other wires in the bike. Many times I've seen a wire change colour as it goes through a connector block. You never know what previous owners may have done either.
Whenever I disconnect wires and it's not obvious where they go, I draw myself a little diagram so I don't get it wrong when it comes to reassembly.
Cheers,
Cam
D
Davo
Guest
Exactly what I did when I dismantled the 3CL. Colour photo of each connector block + my own wiring diagram + end of each wire tagged to say where it came from - and I will still probably get it wrong putting it back together.
