Recommend electronic ignition for 750

Keep the points system. The bike will run no better with electronic ignition. Both my 750's (1968 and 1969) still have the original points. The condensers have been replaced but nothing else. At 2AM in the dark and cold, the points can be fixed on the side of the road. Not so with electronic ignition.

As for the supply of points running out, VW ones can be made to fit with not much effort.

And, always, always keep the advance mechanism lubed. This should be a normal maintenance procedure just like checking the oil.
 
1200ts said:
Keep the points system. The bike will run no better with electronic ignition. Both my 750's (1968 and 1969) still have the original points. The condensers have been replaced but nothing else. At 2AM in the dark and cold, the points can be fixed on the side of the road. Not so with electronic ignition.

As for the supply of points running out, VW ones can be made to fit with not much effort.

And, always, always keep the advance mechanism lubed. This should be a normal maintenance procedure just like checking the oil.
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Whilst I agree totally - take a pair of glasses- mine went onto one cylinder, got the tools and the know how but couldn’t see WTF I was looking at! 😂 Actual problem was slightly lose points wire, saying that I got home on one cylinder - might not have with electronic.
 
Exmoor beast said:
Whilst I agree totally - take a pair of glasses- mine went onto one cylinder, got the tools and the know how but couldn’t see WTF I was looking at! 😂 Actual problem was slightly lose points wire, saying that I got home on one cylinder - might not have with electronic.
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I have an LED head torch and pair of reading glasses these in my old fart toolkit these days.

Does running on one cylinder cause any lasting issues? After I holed the piston I rode on one pot for a few miles to the first service station. Chained the bike to a lamp post and hitched ride home in a truck (driver turned out to live near an uncle so he dropped me at my door at 4am). Those were the days.
 
I fitted a Wassell Vape ignition with an adapter plate from Phil Todd on my SF3. The bike starts and runs so much better, I would never consider going back to points. Fit and forget.
 

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smlav said:
I have an LED head torch and pair of reading glasses these in my old fart toolkit these days.

Does running on one cylinder cause any lasting issues? After I holed the piston I rode on one pot for a few miles to the first service station. Chained the bike to a lamp post and hitched ride home in a truck (driver turned out to live near an uncle so he dropped me at my door at 4am). Those were the days.
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It would be a get you home measure, your only going to limp back, it’s not going to to cause any problems if your motor is ok to start with.
In your case, running lean on one cylinder could well hole the other one! I rode back home from up on the moor, about ten miles and was glad it got me back.
 
My take is Intake manifold air leak - between the carb an intake port of that cylinder - Stick with the point system for the Breganzie 750SF's easily revs to 8000rpm and all you need sand paper and a feeler gauge ;o)

Guess now that you have it all apart - Choice is to keep STD Bore and buy a STD Pistons (You will never find a match for your original pair) or go + 020" or .030"+ for 2 new pistons and rings. Resurface and Lap the Valves, New valve springs - may need guides , NEW rings 30+ and gap to specs , New gaskets - Ensure NO Air leak between the Carbs and Cylinder head a ensure the Balance tube will NOT Collapse (Suggest Hi- Pressure Hydraulic Hose - Been there rebuild her on your Wife's Kitchen table ;o)

If I require new Valve guides I would buy smaller Dia Stems and buy slightly oversized Dia Heads like Manley Ultra lights, resurface the valve seats and do a little bowl porting. (New valve Springs are a Must)

Learned years ago to never trust them stupid rubber "O" Rings inserts fitted into the Heat Shield of them Bakelite spacers - You can repair them spacers using Metal epoxy then use an 3M Amphoric Case Sealer like you use to seal Engine casings. Apply and let dry the Bead can be re-used. I also put it on the Distributor case and drill a 1/8" hole in the bottom to let moisture drain out to keep the points dry after a rain or washing the moped.

When you hole (melt) a piston in a Breganzie or any moped for that matter you have to tare the whole engine and transmission apart, clean and inspect everything. Especially the crank, rod and case bearings - All the Seals will will have to replaced.

You have to question - Just how good of a Mechanic do you think you are ;o)

One thing if you got an air leak between a carb and the intake port a 2 stroke just will not run but a 4 stroke will lean out and burn a piston.
 
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natm said:
I fitted a Wassell Vape ignition with an adapter plate from Phil Todd on my SF3. The bike starts and runs so much better, I would never consider going back to points. Fit and forget.
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If your 750 starts badly with points, it's because you've got something wrong.
It'll start touch of the button as long as there's enough juice in the battery to turn over the starter motor, even slowly. Low battery voltage will put an end to your riding with electronic ignition.
Paul
 
Paul Marx said:
If your 750 starts badly with points, it's because you've got something wrong.
It'll start touch of the button as long as there's enough juice in the battery to turn over the starter motor, even slowly. Low battery voltage will put an end to your riding with electronic ignition.
Paul
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I agree, my 750's with points start with just touching the starter button for a moment and then it idles perfectly even cold. If a bike runs better with electronic ignition, then the points system had something wrong with it. Usually the advance mechanism is worn out from lack of maintenance.
 
Points vs electronic ignition. It's an argument that won't go away, even though there's a clear winner.

Paul and 1200ts prefer to stick with points on their bikes. They have valid reasons and that's fair enough. I'm not going to try to argue with them.

However, it's safe to say that a modern electronic ignition system will perform better than points ignition on any engine. There's a reason points are no longer fitted to new engines. Compared to points, electronic ignitions are near enough to 100% reliable, give a stronger spark, provide better control of ignition advance, and need no regular maintenance. That's not opinion, it's fact.

Points require regular maintenance to keep them operating at their best. They can (and do) fail in a number of ways, but that's mitigated by their simplicity and their ability to be fixed on the side of the road (if you carry a spare set of points/condenser in your tool kit). The greatest advantage that points have going for them is that the bike came fitted with them, and presuming they still work OK, there's little motivation to replace them. You'd need spend a not inconsiderable amount of money to fit an electronic system. It's a personal decision as to whether you think it's worth it. There are people on this forum in both camps.

If you decide to go electronic. You have a number of options. There's a wealth of info on the relative benefits of the various types of ignition system on this forum. You only have to ask.
 
Well since my starting this thread I’ve read more about the subject, and I’ve also bought an SF1 which has an electronic kit fitted. I do like the low maintenance aspect of the electronic. It seems the prime benefit of the points is the ability to make repairs easily; but. I prefer the zero maintenance. I’ll no doubt be fitting electronic to the GTL, which means I will then be able to sell on the three sets of points systems I have, all with condensers, points, backing plate the lot.
 
An electronic ignition will positively change your engine smlav.
I am personaly using the Sachse unit since yearsss.
Never had any issue.
Marco Patzer, the new owner of Elektronik Sachse MHP GmbH & Co, even improved the original design made by Wolker Sashse nearly two decade ago.
Easy to install .. a good choice IMHO.
(I don't have any experience with the Witt unit though)

Good luck.
 
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Thanks Steph, I had comms with Wolfgang who gave me the low down on the various options. Sounds like Witt is good of you want to select from multiple advance curves, but Sachse sounds like easiest for plug and forget. As my GTL is for gentle riding and touring, I’m intending to stick a Sachse on. My SF1 has a Lucas Rita, you don’t see many of them around.
 
As Paul rightly points out, Sachse electronic ignition unit is indeed sensitive to battery voltage.
The minimum voltage required is 5.9V though.

Quotation from the install manual:
".. it should be noted that the ignition performs well under low voltage conditions.
And often if the engine cuts out, it’s in fact the coil not producing a spark any longer rather than the ignition stopping to work."
 
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I've got a Redax/ignitech ignition on the shelf waiting to be installed on my 74 SFC when I get time to recommission it.
I find with the SFC its critical the have the ignition spot on so away with the points.
As for Sachse, have the Redax Sachse fitted to the Motodd. The box failed after about 10000 kays. Luckely only about 4 kays from home.
the centre cylinder dropped out first. Turned around and headed for home on 2 cylinders then the other channel failed about 1 kay from home.
Had to resort to the trusty old 89 GS BM to get me to where I was heading.
Red was kind enough to send me another box and I brought another from Sachse as a spare. It lives on the bike.
 
......or in the day you had transistor assisted ignition, a TA. Reduced the actual primary current and back emf spark duty on the points. Simple circuit of the oem points driving the base or gate of a decent transistor ( many higher performance devices these days ). Reduced the load on the points to "wetting current" duty, few hundred milliamps at worst. That mitigated the actual wearing down of the points, the most significant aspect over lubrication issues.

You get the best of both, simple points and transistor ( just the one ) to have the points last you until old age, which is today by the way for yas all reading this. Of course for less than $10 you use the ST dedicated dwell type IC, have one on my Mazda 929 HD, works a treat and then some, took me 15 minutes and a scrap or FR4 PCB, mentioned this previous for the handy with a soldering iron. BTW with the TA, if the transistor does fail, a simple bypass connection restores the points to the coil primary, quicker than addressing the failed points issue that is the mantra of points for the twins, which am a recommender ( please note, will never be an "Influencer" of the modern ilk...leave that for the people whom aspire to be four legged sheep and cattle ).

As for the "ignition" holed my piston, not possible. Uncontrolled detonation will in an extreme, that is a possibility, though you would have to be disconnected from what a motor is doing during prolonged uncontrolled detonation. Visual is completely different for both types of motor issue. Gross lean out a danger.

As for plug grade, once more am not possessed as to that can damage the piston crown. An unhappy starting or running motor would be the most significant factor or outcome above all else. 7,8,9 have merit. Bosch plugs of the day are bizarre in the heat grade equivalent, i removed them immediately from any customers bikes that came my way.

Posted previous on the actual ST VBG08 IC. Have fun.... yes fun... once upon a time... HTH j.

 
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I remember hearing about the transistor mod that just used the points as a switch with virtually no current through them, someone knew someone who......
I am afraid I doubt that there are many of us here that would have a clue how to use that thing from aliexp in the link.
Holed pistons is (or was) a bit of a known on SF motors, and I agree that the ignition points would not be the direct cause per se, but wrong ignition timing combined with lean running at high speed did not leave much margin. Later SF came to Australia with 140 main jets which were right on the borderline for flat out running, my one year old bike holed a piston heavily loaded with a pillion and luggage on a long uphill at full throttle, there had been heavy rain earlier and both float bowls had a bit of water in them, but the ig timing was correct. I had also been told to fit hotter 240 plugs for some reason. With 145 mains and 260 plugs it did a lot of flat out stuff when I moved to Darwin without problem. SF2 and 3 also came with 40 pilot jets and they were a bastard to get to idle well and need the mixture screws a long way out to try to get them to not pop and die, 45 solved that.
 
Exmoor beast said:
I would stick with points ( points didn’t cause your piston to hole) because you already have them, just plonk a new set on ( VW points with pin removed ) set them up with a strobe and your away. I have original 1969 points, new coils ( VW) and new condensers - starts instantly, runs fine- ideal. Holed piston could well be weak mixture ..
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Which VW model for the points ????????? Thanks
 
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