How about a failing coil? I seem to remember having a similar problem with a bike in the’80s and it was a coil that would only play up when everything was well warmed up. Drove me crazy it did!
No need to worry about earth connection on those bridge rectifiers, the metal case is electrically isolated from the internal diodes (or should be!), metal case is to dissipate heat. If it was my bike I would just build a new loom... Unlike most people I actually like doing electrics!
Just put a new loom (thankfully it’s a very simple loom!) into a T20SH after trying to unpick 60 years of electrical bodges all made in random coloured wires… it’s still not 100% yet! 😂
I'm just going to keep stuchm on this, as I have every faith in your ability to arrive at a solution. having said that, My beloved T90 had an odd misfire when 2-up. Instant cure occurred if the rider (me) stood up. Turns ut the replacement seat would just flex enough to short on the rectifier.
Hi Paul....I had the same mysterious problem on an AJS 500 a few years ago...If I remember correctly it was the wires going to the rear light that was chaffing and shorting on the rear mudguard somewhere. It didn't blow a fuse but just lowered the supply voltage enough to stop the coil firing the plug. With lights off I guess it would not have caused the problem but I ride with them on...I can see though you are thoroughly going over it
I remember similar problem with my T20SH. Dry crimped connectors on the back of the rotary switch above the oil tank. Cleaned every pin with emery paper - took ages! Can't remember whether it cured it permanently. 😊
Hi Paul, have you ever tried the electrical contact grease? It's fantastic stuff. Especially if you're going off road in the wet and wild... All the best David.
Yikes! What is that bundle of home-done crimp connectors behind the ignition switch? Good luck with that push-on plug Paul - it looks like an old radio valve socket! I presume that is courtesy of Geo Lucas, the Prince of Darkness. I sympathize sincerely and it has provoked me to start on a small rant about electrics and killing Gremlins for good.... We all have mechanical connectors throughout the wiring of our cars and bikes and I think they are mostly there to enable quick factory assembly. Over time, some will become troublesome.... susceptible to failure from vibration, dirt, moisture, and heating-up of poor contacts. Additionally, we have use of chassis earth (what, to save a few yards of copper?), where each device has, again, a mechanical connection to earth. A failure of any of these connections will likely begin as intermittent, adding to one's frustration. A solution to all this is to simply be rid of them, wherever possible, with two basic steps: firstly, install an earth wire to each and every device, run back to battery -ve. Secondly, cut out all mechanical connectors and replaced them with soldered joints sealed with heat-shrink tubing (or at least with good quality electrical tape). I few years ago I inherited two bikes with very shaky electrical systems: an Indian Bullet 500 and a 1949 Matchless G80 (6 volt). All Gremlins were solved that way and I even ran an earth to the Matchy dynamo and handlebar horn button. I may have also soldered cable directly onto the horn terminals (can't recall). Anyway, I never had any more problems. Of course you can no longer unplug something to test or replace it, but chances are that you won't need to and if you do, just cut and re-solder. There will be a lot less fiddling with the electrics because so many points of likely failure have been removed. Good soldering is pretty easy (DIY via TH-cam) and heatshrink tubing is fun and comes in all sizes and bright colours. Some is glue-coated inside so becomes waterproof. It gives a nice clean finish as it shrinks down tightly under the heat of a hot air gun and it's not hard to find many other uses.
sounds uncannily familiar with my t20 this! just lately its been almost psychic in defying any effort to just be a reliable cub.. but it won`t defeat me lol,, 😤😎😕
It is another position on the ignition switch to make starting easier if the battery is flat, but not usually good to run on with a fully charged battery.
How about a failing coil? I seem to remember having a similar problem with a bike in the’80s and it was a coil that would only play up when everything was well warmed up. Drove me crazy it did!
No need to worry about earth connection on those bridge rectifiers, the metal case is electrically isolated from the internal diodes (or should be!), metal case is to dissipate heat.
If it was my bike I would just build a new loom... Unlike most people I actually like doing electrics!
Just put a new loom (thankfully it’s a very simple loom!) into a T20SH after trying to unpick 60 years of electrical bodges all made in random coloured wires… it’s still not 100% yet! 😂
I'm just going to keep stuchm on this, as I have every faith in your ability to arrive at a solution. having said that, My beloved T90 had an odd misfire when 2-up. Instant cure occurred if the rider (me) stood up. Turns ut the replacement seat would just flex enough to short on the rectifier.
Hi Paul....I had the same mysterious problem on an AJS 500 a few years ago...If I remember correctly it was the wires going to the rear light that was chaffing and shorting on the rear mudguard somewhere. It didn't blow a fuse but just lowered the supply voltage enough to stop the coil firing the plug. With lights off I guess it would not have caused the problem but I ride with them on...I can see though you are thoroughly going over it
I remember similar problem with my T20SH. Dry crimped connectors on the back of the rotary switch above the oil tank. Cleaned every pin with emery paper - took ages!
Can't remember whether it cured it permanently. 😊
Thanks Paul.
Hi Paul, have you ever tried the electrical contact grease?
It's fantastic stuff. Especially if you're going off road in the wet and wild...
All the best David.
In my experience, the majority of the time electrical problems manifest, it's a ground wire.
Electrics. Like I've said before: witchcraft!!!
i had a bad winding in my coil once,ran bad as it got warm.
Yikes! What is that bundle of home-done crimp connectors behind the ignition switch? Good luck with that push-on plug Paul - it looks like an old radio valve socket! I presume that is courtesy of Geo Lucas, the Prince of Darkness.
I sympathize sincerely and it has provoked me to start on a small rant about electrics and killing Gremlins for good....
We all have mechanical connectors throughout the wiring of our cars and bikes and I think they are mostly there to enable quick factory assembly. Over time, some will become troublesome.... susceptible to failure from vibration, dirt, moisture, and heating-up of poor contacts. Additionally, we have use of chassis earth (what, to save a few yards of copper?), where each device has, again, a mechanical connection to earth. A failure of any of these connections will likely begin as intermittent, adding to one's frustration. A solution to all this is to simply be rid of them, wherever possible, with two basic steps: firstly, install an earth wire to each and every device, run back to battery -ve. Secondly, cut out all mechanical connectors and replaced them with soldered joints sealed with heat-shrink tubing (or at least with good quality electrical tape). I few years ago I inherited two bikes with very shaky electrical systems: an Indian Bullet 500 and a 1949 Matchless G80 (6 volt). All Gremlins were solved that way and I even ran an earth to the Matchy dynamo and handlebar horn button. I may have also soldered cable directly onto the horn terminals (can't recall). Anyway, I never had any more problems. Of course you can no longer unplug something to test or replace it, but chances are that you won't need to and if you do, just cut and re-solder. There will be a lot less fiddling with the electrics because so many points of likely failure have been removed. Good soldering is pretty easy (DIY via TH-cam) and heatshrink tubing is fun and comes in all sizes and bright colours. Some is glue-coated inside so becomes waterproof. It gives a nice clean finish as it shrinks down tightly under the heat of a hot air gun and it's not hard to find many other uses.
sounds uncannily familiar with my t20 this! just lately its been
almost psychic in defying any effort to just be a reliable cub..
but it won`t defeat me lol,, 😤😎😕
Are those red connectors on the rectifier crimped or soldered
Just crimped.
@@paulhenshaw4514 sucks air in through teeth “ you don’t wanna do it like that ….”
I hope you found the gremlin, but have a question. What is a big metal canister under a swing arm, perhaps oil filter?
Hi Adam, yes it is from an oil in frame BSA / Triumph single, I plumbed it in many years ago.
Just wondering what emergency ignition is and how yo switch over to it
It is another position on the ignition switch to make starting easier if the battery is flat, but not usually good to run on with a fully charged battery.
is it the switch again . . .
Not sure ...
I ONLY DO SOLDERED JOINTS NOW. I DONT TRUST CRIMP JOINTS
There are those among us who swear by not soldering them, but I am on the fence with this one, personally.
I always tin the end of the wire that goes into any crimp...
Seems to have worked so far..