Got a 7.5kV one too. It can throw a real angry spark!Haha us sparkies all have 500v testers, it’s quite good fun showing apprentice plumbers how they work
New coils for an SF2
- Thread starter martymoose
- Start date
martymoose
Hero member
- Location
- Sydney, Australia
Nasty coils are gone, neither of them where Bosch, one had no markings, one said hinshin, no idea. Made up a nice bracket, mounted both coils on the rear coil bracket.
Next issue is condensers. Originally rivited on, both mine have been changed, bolt on. They are marked 0.15 uf, which I'm guessing is micro farads.
What is correct, and am I contacting my vintage vw supply's?
Cheers
Next issue is condensers. Originally rivited on, both mine have been changed, bolt on. They are marked 0.15 uf, which I'm guessing is micro farads.
What is correct, and am I contacting my vintage vw supply's?
Cheers
martymoose
Hero member
- Location
- Sydney, Australia
One in Rydalmere as well. Question is, what is the correct condenser?
Tippie
Hero member
- Location
- Dr?bak, Norway
Iirc they were 0.2 microfarad, if it makes a difference.
martymoose
Hero member
- Location
- Sydney, Australia
Thanks tippee ill going shopping online
martymoose
Hero member
- Location
- Sydney, Australia
Thanks Paul!
Dellortoman
Hero member
- Location
- Tasmania, Australia
Points condensers (aka capacitors) are usually 0.22uF. But anywhere between 0.2 and .03 uF should be OK. Your 0.15uF might be a bit on the low side. It'll probably work, but maybe won't be as effective at reducing the arcing at the points, so your points life could be reduced.
Points condensers are pretty reliable things, but they do occasionally fail. If you have a bunch lying around in the workshop, you can check them with a multimeter to see if they're OK.
If you have a multimeter with a capacitance scale you can check the actual value of any condensers you have lying around.
If you have a cheap crap multimeter, you can't check the actual capacitance, but you can still do a check of sorts to see if the thing is working.
First, remove the condenser and discharge it by touching its wire tail to its case. Set your meter on the 20 MΩ scale, clip the red meter probe to the condenser's wire tail and then touch the black probe to the body of the condenser. The meter should start at a low value (say around 3 MΩ and gradually increase through the range until it's off the 20 MΩ scale. It'll only take 3 or 4 seconds, so don't blink or you'll miss it.
If the meter reading stays low, or goes high immediately (or doesn't read anything at all), the condenser is fucked.
The use of condensers is only relevant to points ignition systems. You don't need condensers with electronic ignitions. That's why I refer to them as points condensers rather than ignition condensers.
Points condensers are pretty reliable things, but they do occasionally fail. If you have a bunch lying around in the workshop, you can check them with a multimeter to see if they're OK.
If you have a multimeter with a capacitance scale you can check the actual value of any condensers you have lying around.
If you have a cheap crap multimeter, you can't check the actual capacitance, but you can still do a check of sorts to see if the thing is working.
First, remove the condenser and discharge it by touching its wire tail to its case. Set your meter on the 20 MΩ scale, clip the red meter probe to the condenser's wire tail and then touch the black probe to the body of the condenser. The meter should start at a low value (say around 3 MΩ and gradually increase through the range until it's off the 20 MΩ scale. It'll only take 3 or 4 seconds, so don't blink or you'll miss it.
If the meter reading stays low, or goes high immediately (or doesn't read anything at all), the condenser is fucked.
The use of condensers is only relevant to points ignition systems. You don't need condensers with electronic ignitions. That's why I refer to them as points condensers rather than ignition condensers.
martymoose
Hero member
- Location
- Sydney, Australia
Very interesting topic. Yes, after 4000km the points aren't looking good. They will polish up, but I agree wrong condensers. I checked 7 condensers I have here, only one was testing good, 2 on the bike test bad. I stole Brian's out of his GT, ( correct Bosch condensers) and did a couple of laps, seat of the pants tells me better idle and more torque, crisper throttle. I couldn't get a good reading on Brian's ones with the multimeter, but they work. Hoping new Bosch condensers are not hens teeth
Dellortoman
Hero member
- Location
- Tasmania, Australia
I don't reckon I've bought a condenser in the last 10 years but I think they're still readily availableat reasonable cost.
I've never seen a seller actually provide the electrical specifications of the things though. They'll give a list of what vehicles they're suitable for, but not the uF or voltage specs, so you can't check if a condenser for a VW Beetle, HK holden or Datsun 240 will be OK for your bike. That's assuming you know what specs you're looking for in the first place.
I find this sort of thing interesting so I've been doing a bit of googling, but there's bugger-all info on what condenser values should be. Someone might come along who knows way more about this stuff than I do, but as far as I'm aware, lower resistance coils generally need condensers with a higher uF value. I don't know for sure, but I suspect the optimal uF value could also vary depending the frequency that the points need to operate at. For example, the points in the distributor on a V8 engine will open and close 8 times as fast as the points in a SF Laverda at the same engine revs.
In the absence of actual knowledge about which condenser is right for your bike. I guess you can't go too far wrong if you search for condensers for bikes with similar ignition specs to your Lav 750. That would be anything with points that open and close half engine speed and with similar coil resistance. I guess that means 12V motorcycles that don't have a wasted spark ignition.
On the other hand, maybe any points condenser will do. Perhaps the bolt tab, length of wire tail and type terminal are the most important specs.
Not much help eh?
I've never seen a seller actually provide the electrical specifications of the things though. They'll give a list of what vehicles they're suitable for, but not the uF or voltage specs, so you can't check if a condenser for a VW Beetle, HK holden or Datsun 240 will be OK for your bike. That's assuming you know what specs you're looking for in the first place.
I find this sort of thing interesting so I've been doing a bit of googling, but there's bugger-all info on what condenser values should be. Someone might come along who knows way more about this stuff than I do, but as far as I'm aware, lower resistance coils generally need condensers with a higher uF value. I don't know for sure, but I suspect the optimal uF value could also vary depending the frequency that the points need to operate at. For example, the points in the distributor on a V8 engine will open and close 8 times as fast as the points in a SF Laverda at the same engine revs.
In the absence of actual knowledge about which condenser is right for your bike. I guess you can't go too far wrong if you search for condensers for bikes with similar ignition specs to your Lav 750. That would be anything with points that open and close half engine speed and with similar coil resistance. I guess that means 12V motorcycles that don't have a wasted spark ignition.
On the other hand, maybe any points condenser will do. Perhaps the bolt tab, length of wire tail and type terminal are the most important specs.
Not much help eh?
piranha-bro2
Hero member
- Location
- Melbourne
Hey, Marty, I'm pretty sure I have some genuine Bosch units out on the garage and happy to test and send to you gratis if I can find them. I've probably got them cos I would have replaced them for no reason!
Only prob is I've completely stripped and shifted my workshop from one end of the building to another - hopefully the new shelves and sorting means I can find shit now!
If you can source genuinies no probs, but let me know if you want them.
Only prob is I've completely stripped and shifted my workshop from one end of the building to another - hopefully the new shelves and sorting means I can find shit now!
If you can source genuinies no probs, but let me know if you want them.
Dellortoman
Hero member
- Location
- Tasmania, Australia
Or maybe because you've converted to electronic ignition.
martymoose
Hero member
- Location
- Sydney, Australia
Sounds great Q, no rush. Will has a condenser off his old Ducati which is brand new, so I'll grab that one and modify the bolt hole. Just fitted the one good condenser and polished the points,
GregT
Hero member
- Location
- Christchurch NZ
The only recommendation for condenser capacity I've ever seen was in a Gordon Jennings article in Cycle mag. He did a form of energy transfer ignition for the CB450 Honda he built which used the stock points. His comment was to the effect that "bigger is better " He used in the end a pair of big Mallory condensers - V8 equipment.
On the rare points ignitions I've used I've always gone for a nice big Bosch condenser. They seem to be available off the shelf quite commonly here.
Mounting style and lead length have been my criteria.
On the rare points ignitions I've used I've always gone for a nice big Bosch condenser. They seem to be available off the shelf quite commonly here.
Mounting style and lead length have been my criteria.
martymoose
Hero member
- Location
- Sydney, Australia
Hi Marnix, yes had me thinking why do I need to mount the condensers on the points plate, I could mount them next to the coil. On the SFC are both the condensers wired in?
Velleman sells an electronic ignition (kit # k2543) with it you can avoid the condenser.
On my laverda I have one for each points but i think it could be possible mount just one kit and connect the coils toogether (you'll have the double spark but is it a matter?)
On my V7 just one kit is needed becouse of the distributor.
This electronic kit (diy assembly.... Soldering skills required) avoids also sparks on points and from my experience is much more reliable then the today condensers.
On my laverda I have one for each points but i think it could be possible mount just one kit and connect the coils toogether (you'll have the double spark but is it a matter?)
On my V7 just one kit is needed becouse of the distributor.
This electronic kit (diy assembly.... Soldering skills required) avoids also sparks on points and from my experience is much more reliable then the today condensers.
MarnixSFC
Hero member
Both were wired in, yes. They mounted each conderser on a silent block, with an earth wire of course.
Marnix