Commando rebuild help with possible ignition issue

Tornado

VIP MEMBER
Joined
Dec 5, 2017
Messages
3,031
Country flag
Here's the article comparing various R/R technoligies:


For the Shunting type:
"

Shunting Regulator/Rectifier

In the mid-seventies and early eighties, a popular aftermarket “upgrade” was to swap the standard rectifier and zener for a combined regulator/rectifier.

The very early shunting reg/recs (and even now still the very low-cost ones) are basically functionally a direct equivalent of the original rectifier and zener setup. And there is nothing wrong with this – they work totally perfectly for most people and will provide many years of trouble-free service. Just don’t upgrade your stator to a higher output one, or introduce LED lighting. For good measure you may consider riding with your headlight on, as that continual 3-4 amp current draw acts as a great place for any excess charge to go.

These units are nothing more than a pair of thyristors that are clipping the AC input from the alternator at around 14 volts. The rectifier is then converting the clipped AC supply into DC.


In this example, the ‘control circuit’ that I reference elsewhere in my diagrams is nothing more than a zener diode – it is effectively switching the rest of the unit on or off depending on the voltage in the battery.

However, the DC output was very poor quality and choppy indeed, so over the years the subsequent designs, redesigns and iterations have been refined a little – although you still see these used extensively on lawn mowers, and small tractors to this day.

The simplicity of these is very attractive, and it is the nearest you’ll get to the original rectifier and zener setup.

You should note that a battery and/or a capacitor is an absolute must, as the output needs a lot of smoothing and conditioning.

It is also worth noting that many of these are polarity sensitive – i.e., they are grounded to their heatsinking enclosure electrically as well as thermally, so can only be used for negative earth (if the flylead is red) or positive earth (if the flylead is black) This is particialrly the case for the agricultural ones, so be careful if you are repurposing one for use on your bike.

Also watch out – some of the agricultural ones are rectifiers only – they don’thave regulation built in. Confusingly, they look the same as a reg/rec, so please make sure you know what you’ve got before you fit it.

This type of unit would probably not be recommended (in my opinion) for sensitive electronics like some of the digital electronic ignitions and electronic speedos/tachos.

"
 
Joined
Oct 28, 2009
Messages
902
Country flag
Toronado, the article you quote above does not support your statement:
"Regarding your question on using Typanium Reg/Rec, generally these are known to be electrically noisey".
The Tri-spark site refers to one model of Podtronics reg/rec as "noisy". But I don't think that makes all short-type SCR reg/rec noisy, in general, or the Tympanium reg/rec noisy, in particular.
What do you mean when you say the Trispark Mosfet reg/rec has "built in noise suppression"?
 

Tornado

VIP MEMBER
Joined
Dec 5, 2017
Messages
3,031
Country flag
Toronado, the article you quote above does not support your statement:
"Regarding your question on using Typanium Reg/Rec, generally these are known to be electrically noisey".
The Tri-spark site refers to one model of Podtronics reg/rec as "noisy". But I don't think that makes all short-type SCR reg/rec noisy, in general, or the Tympanium reg/rec noisy, in particular.
What do you mean when you say the Trispark Mosfet reg/rec has "built in noise suppression"?
The SCR shunt types, of which the tympanium is one, are shown to have a more irregular wave form than the MOSFET in the article.
From the author in the last line that I quoted:
"This type of unit would probably not be recommended (in my opinion) for sensitive electronics like some of the digital electronic ignitions and electronic speedos/tachos."
 

maylar

VIP MEMBER
Joined
May 13, 2007
Messages
4,107
Country flag
Then again. SCR shunting regulators have been used for a couple of decades and the TriSpark is the only problem child that I know of. I had a Sparx SCR regulator and TriSpark ignition for 10 years without issue. I don't see that we should generalize this design as being "noisy".
 

Time Warp

.......back to the 70's.
VIP MEMBER
Joined
Dec 3, 2012
Messages
3,214
This could be an answer. I had thought along those lines as a solution so shall give it a try.

Use it sparingly even if it takes more than one attempt.
It is good as a locking agent that maintains some give (unlike Loctite)

I use the same thick Suzuki Moly paste as the other thread on the Bellville washer at the bottom convex down.

The Bellville is the same as the one on the OEM kickstart lever, wrong way up and it will not hold position.
 

johnm

VIP MEMBER
Joined
Feb 26, 2008
Messages
1,108
Country flag
You are not alone. I spent a ridiculous amount of time fiddling with one of those Far Eastern pieces of crap a while ago. I ended up using the ‘elastic band to keep it open’ method until I managed to find a decent original which worked perfectly.
In the past few days I have scoured mine and a couple of friends old parts boxes to assemble a decent original. Unfortunately visually most are very rough. But mechanically they actually work.

Manufacturing replacement parts is a waste of time if they don't actually work. Very annoying
 
Top