Transistorized Ignition for Dual Points

74ok · Nov 18, 2014

could this be modded to work with positive ground?

http://sohc4shop.com/catalog/product_in ... a27300acb4

This Electronic Ignition for your motorcycle (and for old cars or boats, contact me for those details) uses your existing points to trigger transistors that switch the coils in the bike's ignition: in effect, it is like a "points amplifier". This stops all the arcing and pitting on the points, so they do not shift in timing nor wear their contacts, giving you many years of trouble-free riding. And, should this device ever fail, it can be simply unplugged and your points plugged back in, so you can ride on. They are highly reliable units, and have been around since the 1970s

orthis?
http://home.comcast.net/~loudgpz/GPZweb ... oints.html

http://home.comcast.net/~loudgpz/GPZweb ... vCoil.html

Time Warp · Nov 18, 2014

There should be a few options, I got a unit for my Sunbeam (single points though) that uses the distributor points to trigger the unit.
They are common on eBay.uk.
Of course I have started converting the bike from 6 volt positive to 12 volt negative earth so it is unneeded now. :roll:

Hobot · Nov 18, 2014

Yeah man that was a good device for contact breaker ignitions from late '60's on. I used one for an outboard in Fla back then but is not worth while on Nortons until-unless you have solved the AAU wear out sticking issue.

74ok · Nov 18, 2014

more stuff on the homepage
http://home.comcast.net/~loudgpz/GPZweb/index.html#home

-Homemade voltage regulator for permanent-magnet alternators
-Homemade voltage regulator for excited-field alternators (Not for GPZ)
-Homemade 3 phase rectifier (with no auxiliary output)
-AC regulator for 6 volt scooters or other magneto driven bikes (Not for GPZ)

DogT · Nov 19, 2014

I thought about that, but like hobot says, the AAU is the killer. Plus for about $200 the Pazon SureFire is so easy unless you have to trade out the 12V coils on the early bike like me. Hardly worth the time and effort. But, yeah, you'd still be using the points.

Hobot · Nov 19, 2014

it is interesting and useful for those changing firing angles in mulit jug engines plus DIY tinkers. Go for it and service the AAU if still working and should work a treat for many 1000's of miles, maybe even couple dozen 1000. Used to be the electronics were a bragging point but now maybe the other way around. I do like every thing about point behavior. They allow some extra 'fun' to get contract lasting by fine tuning the condensors for a clean one shot snap w/o the erroding sparking of back washing EMF. Most points all about the same surface area so about any condensor surpresses fast eroding but age and material conduction differences and wire paths have detectable effect, which is what allow attending to it.

74ok · Nov 19, 2014

i'm not clear how or why aau is the killer?

prob most of the bikes that stuff is for have AAUs

74ok · Nov 19, 2014

hobot said:
I do like every thing about point behavior.

i like points too,

points and magnetos are widely used in aviation piston engines to this day,

that tells a story

kerinorton · Nov 19, 2014

Yes that may be correct, but aviation engines are constant rev engines usually, so don't need the aau.
I agree with the comments. My 750 is for me to be proud of the fact that I have a neat commando in near new condition. It's good to look at and goes like hell.. It runs well on the points but will hardly be used. I use the 850 all the time and don't really care that it doesn't look perfect. We used to fit ignition modifiers years ago and the advantage is extended dwell time and less current going through the points. All you had to do was keep the cam greased and make sure the points gap was correct. I f you fit something like this to a commando, you will have to run a separate unit for each set of points. [ Correct me if I am wrong. ] So why not fit complete electronic?
Dereck

Hobot · Nov 19, 2014

The mechanical advance get nil lube so wears most in full advance position so tends to stay there so idle will not go below almost 2 grand even dial carbs back till it just stalls. I've had a lot of practice nursing them to retard at traffic lights by using brake and clutch to drag engine down enough the AAU would fall back to retard, for a time, any blip at all ran it back to 2000ish sitting still. I stated to set up to restore AAU's but too many side disasters so far. I've seen a few new ones offered over 2 decades, $80 to $150

acotrel · Nov 19, 2014

How much does the commando auto advance retard the ignition timing, later than 28 deg. BTDC and below what revs? Does the motor pull better from very low revs when the ignition timing retards, or is this about smooth idling and avoiding pinging with crappy fuel ?

Rohan · Nov 19, 2014

One of the problems said to be associated with the Combat saga was that the aa would not auto retard when needed,
and putting bigger stresses on the main bearings at low rpms. (since the spark was still fully advanced).

Riders were said to be oblivious to this, although I would have thought a high idle might have shown as a problem ?

AA is fully advanced by 3000 rpm (from memory ?).
Don't quite recall how many degrees they operate on, some are stamped with this number ?

kerinorton · Nov 19, 2014

hobot said:
The mechanical advance get nil lube so wears most in full advance position so tends to stay there so idle will not go below almost 2 grand even dial carbs back till it just stalls. I've had a lot of practice nursing them to retard at traffic lights by using brake and clutch to drag engine down enough the AAU would fall back to retard, for a time, any blip at all ran it back to 2000ish sitting still. I stated to set up to restore AAU's but too many side disasters so far. I've seen a few new ones offered over 2 decades, $80 to $150

Yes that's the problem with them. They need to be lubed regularly but its so much work to do it. The points plate will never sit back in the same position so you are left pissing around adjusting its position to get the points gaps close to being the same then retime ignition. I remember the effort when I put my 750 back together. I had my son work the timing light and when I advanced the plate he told me it retarded the timing [ because of the excessive play ]. Could not believe my son at first when he said the timing was going the wrong way. After 40 years of not touching it I forgot how tricky the were. How many "Poor" Norton owners would have gone ape shit with the bills from the bike shops for tuning the bikes, [ every 5,000 miles or so maybe??????? ]
Dereck

Rohan · Nov 20, 2014

kerinorton said:
How many "Poor" Norton owners would have gone ape shit with the bills from the bike shops for tuning the bikes, [ every 5,000 miles or so maybe??????? ]

I thought the concept of a British bike was that you did the work yourself ?
The Owners Manual for many a year describes all the regular tasks and even many possible problems and solutions.

Some have said this was the Japanese clever bit - developing bikes that could be left for the Dealer to maintain and service.
Such that you didn't need to be a full time mechanic to keep it on the road. ?
Or even get your hands dirty....

DogT · Nov 20, 2014

I found the biggest problem with my AAU was not the advance, but the erratic timing. You couldn't set the dwell angle nor the advance to any particular point, it was always wandering around. I think mine had about a +- 4 degree variation. Someone came up with a brass bushing for the AAU and also played with the dwell angle.

I'm dragging up old history, this has all been hashed over before.

Hobot · Nov 20, 2014

Before the early 60's when our B.I. twins developed cost was everything so made do with labor intensive DIY mouse trap sparker that can wander beyond 5' either way. Full AAU adv hits about 2500. Still when working right points are wonderful even with the sloppy stability and is one level of vintage appeal - how nice obsolete stuff can be made to work, for a time, if ya the time and mood for it. Thanks goodness no law against marrying more than one motorcycle like there is spouses to settle on just one with tolerable maintance or performance quirks.

74ok · Nov 20, 2014

kerinorton said:
Yes that may be correct, but aviation engines are constant rev engines usually, so don't need the aau.
I agree with the comments. My 750 is for me to be proud of the fact that I have a neat commando in near new condition. It's good to look at and goes like hell.. It runs well on the points but will hardly be used. I use the 850 all the time and don't really care that it doesn't look perfect. We used to fit ignition modifiers years ago and the advantage is extended dwell time and less current going through the points. All you had to do was keep the cam greased and make sure the points gap was correct.[ Correct me if I am wrong. ] So why not fit complete electronic?
Dereck

well one feature i like is if the transistor side acts up, you can flick a switch and run the normal points setup, unit has an appealing price too
http://sohc4shop.com/catalog/product_in ... a27300acb4

3. Points and condensors stay in place: this provides 100% backup if the electronics should ever fail. You can unplug the 4 wires to the points and coils, plug the points back into the coils, and hit the road again in (literally) about 2 minutes, even on a hot bike.

not sure about this? is that how you get around the negative ground issue?

I f you fit something like this to a commando, you will have to run a separate unit for each set of points.

any info on the stuff that has been already tried and used in the past (amplifiers etc) that some folks have mentioned?

Transistorized Ignition for Dual Points

74ok

Time Warp

.......back to the 70's.

Hobot

74ok

DogT

Hobot

74ok

74ok

kerinorton

Hobot

acotrel

Rohan

kerinorton

Rohan

DogT

Hobot

74ok

Similar threads