Author Topic: Transistorized ignition, points style. First ones are ready! (Read 81771 times)

HondaMan · « **Reply #50 on:** December 01, 2006, 08:07:44 PM »

Quote from: Kevin400F on November 30, 2006, 03:12:51 AM

Hondaman, what is your opinion of the circuit at the URL below? It appears to be a bit more complicated that what you're planning. Are all the extra components warranted?

http://www.cs.berkeley.edu/~wkahan/TransIgn.pdf

It seems like someone else also asked me about this one...this particular circuit uses quite a bit more current than the standard Kettering approach. With the power budgets on these older Hondas, I like to stay away from tricky things like these, just in favor of reliability.
A CDI will work on these Hondas, for example, but you need to trade off something else to get enough power to run it: a typical CDI uses about 3 amps more than the coils it feeds. The old Kawasaki 500 twostroke triple had CDI, and every one I ever saw either ate the CDI from a dried out, heavily-worked battery that raised the system voltage to 16 volts (which then overheated the CDI power oscillator, making toast), or else the battery was always half dead, so guys were jumping them from someone's car on Saturday nights to go for a ride. On a CB750K4 or later, disabling the "running lite" feature of the front turn signals would usually be enough to get you there, so long as you stayed with the stock sealed-beam headlight. But, adding a halogen light and a CDI would guarantee trouble.

I don't need that, and I bet most of you don't want it, either...

HondaMan · « **Reply #51 on:** December 01, 2006, 08:12:53 PM »

Quote from: Kevin400F on December 01, 2006, 04:27:49 AM

Excellent point, Raul. Although the points open/close events are exactly 180 degrees apart, the opening event is a "positive" action...the points are pushed open by the points cam, whereas the closing event depends on spring action. In the OEM setup, if you get point "float" as the spring-loaded points are trying to keep up with an 11,000 rpm engine, the worst that happens is you sacrifice a little coil charge time. If you were dependent on points closing to fire the ignition, there is the potential the timing would be retarded.

Thanks, Kevin

In the case of our Hondas, the points cams are also ground for a quick opening and a gentle closing (with the CB450 twin being the most radical of this feature...). The quick opening makes them start and idle better, while the gentle closing prevents a small bounce that could fire a lesser spark at an inopportune time. Don't forget, some GM systems were engineered to fire on points closure, but these are naturally spring-bounce limited to 5000 RPM or so: not terribly useful in our situation. Their system was reliable, and it naturally prevented over-revving of those certain hi-po engines: no small engineering feat! It takes a lot of extra circuitry to make an RPM limiter when you need one.

Jonesy · « **Reply #52 on:** December 02, 2006, 05:52:14 AM »

Quote from: HondaMan on December 01, 2006, 08:12:53 PM

It takes a lot of extra circuitry to make an RPM limiter when you need one.

OMC had a nifty solution on outboard motors from the 1950's. They too relied on the points floating at a predetermined speed to keep the engine from over-revving. However, aftermarket points used heftier leaf springs as they believed the floating to be a flaw, since 2-stroke engines tend to put out more power the faster they turn. (The old, "Unlock more power! Use our stuff!" approach..) After getting word of too many engines blowing up after using aftermarket points, they added a vacuum switch to the intake manifold and when the manifold vacuum was high enough it would close the switch, shorting out one set of points and killing a cylinder.

This wouldn't work on our carb-per-cylinder machines, but if we had a manifold feeding everything it could be a simplistic option.

750goes · « **Reply #53 on:** December 11, 2006, 01:04:43 AM »

Hondaman, sorry just following up, what is the end result, are you going to make a few of these for those who want one??
thanks, I appreciate your reply..

kettlesd · « **Reply #54 on:** December 11, 2006, 04:29:19 AM »

Me as well hondaman - if you'd ship to Canada, I'd love to have one of those.

Terry in Australia · « **Reply #55 on:** December 11, 2006, 04:55:12 PM »

Just remember that I was first in line men...............

750goes · « **Reply #56 on:** December 11, 2006, 05:37:53 PM »

Terry, you remind me of a T-shirt I saw

yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
yeah yeah yeah yeah yeah yeah yeah
blah blah blah blah blah blah blah blah
don't tell me your life story
just show me your tits

You are first,, I am somewhere behind you

HondaMan · « **Reply #57 on:** December 11, 2006, 06:23:56 PM »

I got the big transistors last Friday or so, and I am setting up a test fixture with some old CB750 and CB500 coils I have. I'm going to test-run the circuit for several weeks before finalizing the design so I can give it some durability testing. If all goes well, I should have some available in January sometime, I'll keep updating here while it's going on.

It's hard to calculate the heat losses in the transistor, so the best way is to estimate, then test. To me, reliability is everything...

Along the way, I found that I might be able to add a dwell extender to the circuit, which will prevent the spark droop so common in the Honda coils at 7000+ RPM. That would be nice, not especially necessary, but if it works easily, I'll add that, too. It's only 2 more parts.

I got enough transistors in this first batch for 10 4-cylinder bikes (2 circuits per bike). There's more transistors available, so there's no worry there.

750goes · « **Reply #58 on:** December 11, 2006, 06:51:56 PM »

thanks..happy transistoring....

Terry in Australia · « **Reply #59 on:** December 12, 2006, 01:28:23 AM »

Quote from: 750goes on December 11, 2006, 06:51:56 PM

thanks..happy transistoring....

Stop sucking up mate, it doesn't matter how much Hondaman pole you smoke, I'm still #1! Ha ha, Cheers, Terry.

750goes · « **Reply #60 on:** December 12, 2006, 02:04:32 AM »

Terry.........thats the pot calling the kettle black isn't it....

...no harm in trying anyway.......it was 40 bloody degrees in Penrith yesterday, today was 23 and drizzle....miserable as.......but no real rain again....I'll try and find some old condensors as well... suck suck suck.......

Terry in Australia · « **Reply #61 on:** December 12, 2006, 02:36:36 AM »

Ha ha, no worries Charlie, I went to the V8 supercars at Phillip Island to watch poor bloody Lowndsy get shafted by P-Rick Kelly on Sunday, and it was 42.1 deg C (108 deg F for our American friends)in the shade, but if you know Phillip Island, there is no f*cking shade!

The Jack Daniels "Virtual Distillery" van thing was doing a roaring trade, as it was airconditioned inside, but there were no free samples, and the bastards kept kicking me out for licking the pictures? Hell, lucky for them their whiskey is just about the best thing I've ever had in my mouth, or I wouldn't have gone quietly...............

Do you need some condensors? I've probably got some in a box somewhere?

750goes · « **Reply #62 on:** December 12, 2006, 02:46:38 AM »

nah mate I was going to send some to Hondaman... he needs maybe a few for his testing of the transistor thingies..

kelly was a p-rick and did not deserve just a black flag.. if I was Lowndes, I would have waited for him on the track and bounced him around a bit to even it up, Lowndes had no chance with bent suspension - after the unfortunate and untimely incident...

were the bar girls the ones you were licking - the pictures off their t-shirts

....glad it was hot - the only way to tell you had a nice day - f'n hangover the next...and red neck to boot.....

I'm off to bed - early start tomorrow....see ya

dusterdude · « **Reply #63 on:** December 12, 2006, 05:53:39 AM »

750goes · « **Reply #64 on:** December 12, 2006, 12:19:20 PM »

huh ? dd wassup ?

dusterdude · « **Reply #65 on:** December 12, 2006, 12:31:56 PM »

oh they`re talking all that austrailian jibberish and i dont understand it.

750goes · « **Reply #66 on:** December 12, 2006, 02:57:51 PM »

dusterdude,

I was commenting to Terry, that if he had a good day out, he would have had a big hangover and a sunburnt neck...and at most Australian Motor Sport events, be they motorcycle road racing etc,, they always seem to have a hospitality tent, where you can go and get legless, and most times these tents are hosted by lovely young ladies who serve you the drinks in a very sociable manner...and they always wear the promoters T-shirts to their best advantage - be they wet or not....
sorry for talking strine at you..

the two main drivers at this final event of the year were invlolved in little push and shove incident which while most say and even the officials sort of said it was just racing, resulted in his main competitor to finish well back with no chance of winning the event due to damaged suspension, and then the other driver went on to win the championship... it was not the real aussie spirit of getting a fair go... though some would say that's just racing..

dgfischer · « **Reply #67 on:** December 30, 2006, 06:00:20 AM »

Has anyone tried this ignition amplifier ?

http://store.qkits.com/moreinfo.cfm/K2543

Daniel

HondaMan · « **Reply #68 on:** December 30, 2006, 04:46:30 PM »

Quote from: dgfischer on December 30, 2006, 06:00:20 AM

Has anyone tried this ignition amplifier ?

http://store.qkits.com/moreinfo.cfm/K2543

Daniel

It sounds like the same general idea as the one I'm building now, although mine will allow up to 6+ amps coil current. I am enclosing mine in a watertight aluminum enclosure, too. The hookups are the same. The enclosure costs as much as the electronics, but that's where the reliability will come in...

If anyone gets one of these, I'd be interested in seeing a schematic of the gadget!

750goes · « **Reply #69 on:** December 30, 2006, 05:31:00 PM »

Hondaman,

I know very little about electrics, so just asking a question - the kit that Daniel mentioned showed a sketch of how to hookup the system, and I have trouble working out if you connect to where the condensors were connected , then you need two wires??

HondaMan · « **Reply #70 on:** December 30, 2006, 10:15:23 PM »

Quote from: 750goes on December 30, 2006, 05:31:00 PM

Hondaman,

I know very little about electrics, so just asking a question - the kit that Daniel mentioned showed a sketch of how to hookup the system, and I have trouble working out if you connect to where the condensors were connected , then you need two wires??

No, the wire from the coil comes down to the points and connects at the same spot as the condensor. So, you would just remove the condensor's wire and add the wire from the ignition module to that same spot (which is a tiny bolt on these bikes).

HondaMan · « **Reply #71 on:** December 30, 2006, 10:25:10 PM »

It's ALIVE, it's ALIVE!

I got the prototype running tonite! here's some pix of the setup (in a darkened room so you can see the displays). I had it running at 900-ish RPM, 6500-ish and 10,000+ RPM during this first test. Next comes the endurance tests. The waveform on the 'scope is the collector of the drive transistor, which is taking the place of the points. The most noticeable thing at this point is the improved intensity of the spark, very solid and blue, no yellow tinges. It's running both sides of a Honda CB500 coil.

HondaMan · « **Reply #72 on:** December 30, 2006, 10:26:02 PM »

Sorry, had to split up the pix, too big...

750goes · « **Reply #73 on:** December 31, 2006, 03:08:35 AM »

So you will have two connections attaching one each to the two points instead of both condensors on the points plate...yes ??

thanks for the perserverance with my non-understanding question....happy new year

those graphs look good - I presume from the images that the higher and more even display is when it was revving at 10k..

hotrod101 · « **Reply #74 on:** December 31, 2006, 04:18:57 AM »

hondaman...i am a nubie but sounds good if you get caught up with those that already want one put me in line

thanks
john

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Author Topic: Transistorized ignition, points style. First ones are ready! (Read 81771 times)

kettlesd

dgfischer