Still 750 sf2 running problems

Good point, but have checked it, polarity is good on all connections
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Are the white dots on the magnets facing outwards? - ign will retard as revs rise if not. I run all my 750's on Boyer stuff - strangely enough - all are using boxes returned to me as not working! if you can remove a magnet without damaging it - try running with only 1 magnet. - Regards - Phil
 
Boyer also do a "universal" box which changes the load on the points down to zilch, on an SF you would need two.

To try and eliminate the fault I would substitute standard points, condensers and coils set up, so simple, and if it proves to be a great runner you can carry on as is, and pick up a new electronic system later if that is your desire.
CLEM
 
Thanks for advise, as ever some is more useful than others but they all give me ideas to go on with what to investigate.
I can't fit points etc, as I don't have any of the parts, just looked up the cost on Laverda-paradise to change back and it would as expensive as a DMC ignition.
No idea what jets are inside as I haven't stripped the carbs, but the SF2 had 140 main jets anyway, it has fairly open after market exhausts and no air filter, but the
Inlet rubbers are good, could be I need to strip the carbs, but dont reackon the carbs or crank seals will make the ignition go to full advance on tick over.
The magnets are the correct way round but I will try removing one as Phil suggested, and I will check the ignition timing again.
Although using actual Laverda SF instructions in English would be preferable.
The sprag clutch is located correctly on to the woodruff key.
Prior to the present problems the bike was running relatively ok, although I did suspect the very occasional pinging.
It's a bit like when Eric Morecalme played the Piano for Andre Previn, all the notes were correct, just not necessarily in the right order.
But I will preserve a little longer as I might have missed something, if I do decide the change the ignition it will probably be for a Sashse as I want something that is easy to fit with simple instruction and little lights built in, that tell me where the spark is, (most probably do nowadays) but I don't want anything that I can re-map the ignition using a computer, (personally from my point of view, being a total Luddite having the ignition curve set correct in the first place should be as given, otherwise why are they so expensive). Just something that will make it go bang at the right moment, as I'm not planning to enter the TT on it, if I wanted a more complicated faster bike I would have brought one,
It's a 47 year old bike ffs.
 
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Hiya Buddy
We spoke at the last meeting a couple of weeks ago and I dragged Rob B over to try and help you. Now this may or may not help but I look after an old Triumph for a mate with absolutely no mechanical knowledge whatsoever. When he bought it, the thing was running badly after an enthusiastic amateur restoration. Usual story of looking a million dollars and "just needs a little fettling" situation. Long story short it had totally worn out carbs, two rectifiers wired up and an old Boyer ignition which had seen better days. He wasn't worried about cost so new carbs, new harness, new reg/rec and a new Pazon ignition kit had it running like a good 'un. Fast forward two years and the bike had broken down after popping and banging and cutting out. Initial checks found nothing amiss and I could only conclude that the ignition module had gone down. "Just replace it" was the reply when I told the guy what I thought was wrong. A couple of days later whilst fitting the new ignition I found a broken wire (well hidden) which was the power feed to the module. Fixed the wire and the bike fired up immediately and all was good. Further investigation led me to believe that the lack of power to the box leaves it in a fully advanced state. Normally, when you switch the ignition on it electronically retards for starting and then advances as the revs increase. The faults I found were despite a fat healthy spark on both cylinders and the timing spot on it would backfire and try to break your leg when kicking it over. So I suggest you check the wiring from the Boyer ignition box to the bike and any fuses involved. If that checks out OK, junk the box and fit a new one cos, it's bust.

Take Care Bob

P.S. Brand new Pazon ignition for sale, still in box.
 
Hi Bob,
Yeah I recall our discussion, bloody motorcycle.
I will have to check all the wires again, could well have missed something, can't work out what I'm possibly doing wrong,and I'm not totally without experience fitting electronic ignition, as I fitted a Rita system to my Ducati bevel and that was probably more complicated than this Boyer set up.
I was hoping someone would advice me the remove the system from the bike post-haste and kill it with a hammer, as it would never run properly again and I was running myself into an early grave trying, but everyone has been much too helpful, giving guidence that might solve the issue without me needing to spend a fortune.
I've got all weekend to mess with the thing now, (boss indoors allowing) before I make a decision Sunday evening.
Would the Pazon fit?
 
No, mate. The Pazon will only fit Triumph and BSA unit twins. Having read your other post I'm almost convinced your Boyer is faulty because you're doing everything right with the possible exception of always rotating the crankshaft clockwise to the desired TDC position as Hamish suggests. Setting the timing statically is only a starting point until you strobe it at full advance which is around 4000rpm. That's a pain because you need two people, one to hold the throttle and one to strobe and adjust the back plate all whilst the bike is vibrating around the garage. It's easy on an old Britshit twin, find a straight bit of road and ride up and down under hard acceleration and keep stopping to advance it up. When it starts pinking, back it off until it doesn't and that's it. Suggested (printed) timing figures for any bike are only a guide when different fuel and wear and tear are taken into account. My jotarised 3CL had to be retarded to 28btdc to get rid of pinking, now it's fine. Tomorrow, who knows?
Look, you've got an expensive paperweight at the moment giving you nothing but grief and life is too short. Trust me, junk the Boyer, ring Keith Nairn and buy the Ignitech system. The fitting instructions are very good and the adjustment by using a laptop is a piece of piss (after Rob B explains it). Hell, even I can do it and I'm a total Luddite when it comes to computers. Upload photos like you have? Forget it.
 
I had a very similar problem with my 750 SF2 fitted with a Mk3 Boyer. The bike was very hard to start, usually needed a squirt of easy start and wouldn’t tick over.
now it starts immediately, ticks over at 900rpm and revs smoothly and quickly. My experience points to the Boyer not operating with low battery voltage. This is a known problem and one of the main reasons that Boyer introduced the Mk4 unit. Pazon have also reported the same experience and quote their unit as fixing the problems with the Mk3 at low voltage.
I had a Motobatt fitted that sat on ‘green’ on the Optimate and read a steady 12.6V at rest. I think the cranking demand was pulling the voltage down to a point where the Boyer has problems.
So, my solution worked perfectly but a bit expensive….
Replace the Motobatt with a lithium Shido battery
Replace the Boyer with a full Sasche system
Two single Dyna 3 ohm coils.
New HT leads and NGK plug caps
New spark plugs NGK B8ES
Hope this makes sense and helps.
 
All my 750s except the Electronica run points and I have never had an ignition related problem, whatever the level of the battery.
The only ignition problem I've had in 30 years riding the things is a dead coil. That's in about 150 000 km of 750 use.

Paul
 
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you have Paul you just don't know it, because the engines are quite forgiving and flexible, you are not aware of the ATD bouncing around all over the place giving large and small amounts of advance when its not needed or even when it is, and again, if the points gap is not identical , and you have not strobed both cylinders individually, it will still run just fine, but you don't know that the timing is different on both sides, those problems are there, but they just don't cause any grief, and why not, just carry on, you are not racing and every last unit of horsepower is not vital, my own SF experience in the early 70's reminds me that the points last about five years or 40,000 k's or miles (owner can choose), I always carried a spare and pre-set up ingnition backplate, but never needed it, the original system is so good on the SF it puzzles me why people do change it, but hey ho, I have even got a smart phone now, in the old days you had to stop and use a public phone box, every single time you got through unlike the smart phone which does not work when I am at home.

"Modern" people will want electronic ignition, and that's up to them, and Yes I have one on the Egli, its a Boyer but long before Phil was engaged with them, mine is a twin pickup unit from a Norton Commando, it doesn't advance fare enough and so that will go back to points.

Am I right in thinking that the young guns that set up Pazon are in fact ex long term Boyer employees? (albeit in the other side of the globe) hence the similarities and interchangability.

CLEM
 
You are of course completely right Clem and I'm totally aware of the advantages of electronic and the shortcomings of points and mechanical advance.
Only:
- nearly all of the problems with 750 ignitions on this forum concern electronic ignitions.
- as you mention, I'm not short circuit racing, I ride quite a lot so I need a reliable system that can be fixed by the side of the road. When going long distance, I carry a complete spare points plate complete with condensers, and a spare coil since as mentioned, a coil is the only thing that has left me by the side of the road in 30 years.
- I don't thrash my bikes, I've got over that. There's video games for those interested. I plod, often and far.

Paul
 
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