SOHC.co.uk Forums > CB500/550
Electronic ignition
deltarider:
Ok, I'm here to learn.
Let's select the CB400F, which in standard config. revs up to 10.000 rpm, and then let's assume you are a specialist and have tuned your bike so far, it will now rev up to 12.000 rpm.
So let's imagine you are comfortably cruising down some countryroad, at 12.000 rpm, minding your own business. You even have time to do some calculation.
12.000 rpm = 200 rpm/sec, meaning the damned thing, with its double distributorless/wasted spark ignition, fires 200 times a second. So... correct me if I'm wrong, for each revolution there's 1 sec:200= 5ms or 5000 μs time for a complete firing sequens, right?
Now, let's have another look at what the Dutch engineer putting the Velleman to the test, has found (see pic below). BTW, it's only been a few years that I have discovered that test, which also was about other ignitions like the Accuspark, Lumination and the 123. The rise time of the Velleman is pretty short with 25 μs. Interpreting that graph, am I right to conclude that - fighting the back EMF and all - the coil is nonetheless fully saturated in a little over 50 μs? Meaning the rest of the time, is in theory available for discharging/sparking? Taking into account a duty cycle of 51-55%, what more could you want? BTW, note that the Velleman can fire up to 500Hz!
Now this test was carried out using a Bosch supercoil. Back then they were 3Ω IIRC.
I myself run 3Ω coils. I don't know why I ever bought them, but let's not go there now.
The point is... I cannot for the world see which EI - with no matter what fancy names - can offer me more, given the baseline, I want to maintain my breakerpoints, which I'm famliar with and which, ever since I mounted my transistorized ignition, see a very modest current (I measure 6V), just enough to stay clean.
Please correct me, if I have made a wrong assumption somewhere.
If someone with more knowledge than me, sees room for improvement, I'm all ears. Was I right to fit the somewhat smaller 400v MKT B32523 capacitors or should I obediently have followed the original scheme and have the 630V capacitors? In other words, what is the consequence of my choice?
I can recommend the location I've put my EI in. In all those years. the unit has not moved a mm. I guess that protruding little screw helps in this respect. I was surprised to find so much space behind the cover. The box I used was a diecast Hammond 10 X 5 X 2,5cm, IIRC, but - caution - that one was a very, very tight fit to squeeze the two prints in, even after shorting the power transistor's three legs and having them – the transisors – bend over as far as possible. One of these days I'll have a look with my cheap little endoscopic camera and see if there's even some more room behind that cover for a slightly bigger box. As said, I've abandoned the heatfins, which are an exaggeration IMO and have used the bottom and the lid of the alu box to let the power transistors dissipate their heat.
Johnwebley:
my own preference is EI,because of no moving parts,
Boyer uses magnets,rotating near the pole of the coils,
and a later purchase for my RD yam, made by Vape,uses the "Hall" effect,( I think).this is because the cam is corroded so badly as to be like a cheese grater,as is made of unobtainium.
https://www.vape.eu/en/yamaha-125-rdx-engine-1e7
BTW, this thread has caused me to buy a Beginners Guide to Electronics book,
never to late to learn.
Sesman:
Deltarider.
Simply out of interest, have you come across an economical way to create a contactless trigger solution, not that you see any benefit of course.
allankelly1:
--- Quote from: Johnwebley on January 16, 2022, 03:25:27 PM ---
my own preference is EI,because of no moving parts,
Boyer uses magnets,rotating near the pole of the coils,
and a later purchase for my RD yam, made by Vape,uses the "Hall" effect,( I think).this is because the cam is corroded so badly as to be like a cheese grater,as is made of unobtainium.
https://www.vape.eu/en/yamaha-125-rdx-engine-1e7
BTW, this thread has caused me to buy a Beginners Guide to Electronics book,
never to late to learn.
--- End quote ---
Hi John
Got to say love the Vape system and fitted this to my RD350LC too
Will never look back as it replaced both the original charge system and original ignition cdi and coils with a modern electronic set up that is well proven
Plus flywheel is half the weight of the original that places less stress on the crank and make the engine more free revving
Also got full Boyer system on the CB400F
Again well proven system and like the the idea of no mechanical moving parts other than a magnetic trigger plus cdi and coils that runs faultless and if I do break down I have full recovery
Sent from my iPhone using Tapatalk
AshimotoK0:
Deltarider (sorry I don't know your first name :-[ my bad) ... the 'transistor switch' type ignition like the Velleman kit switches from the points so the transistor switches for the same time as the conventional system and with it's 0.2uF capacitor storing the energy from the coil I would imagine the performance to be the same as the points type ignition. Personally, I would retain the 630v capacitor .. Velleman have sold a lot of those kits and probably chose the higher voltage device (which is more expensive) for increased reliability.
I agree that a Hall-effect pointless system is to be preferred but we are talking about DIY type systems here similar to the Hondaman system, where if you get an electronics failure, you can simply switch back to standard. people will chine in " i am perfectly happy with the original Honda system' and I would agree.... as long as you fit Denso/Tec/Hitachi parts, possibly even Daiichi if they are the ones made in Japan.
My friend (has a sprint CB500K1) and two of his friends in York bought these fancy pant's systems, which cost a fortune but have been given to me to attempt to fix as they have all failed in service.
You are probably looking at a picture below of around £2.5k's worth of scrap.... they all went out and cut their losses and fitted Dyna systems, which I gather have performed OK.
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