750 sf advance?
- Thread starter coolRGS
- Start date
Ernesto
Hero member
- Location
- Hamburg, Germany
Have you already checked with a strobelight?
ernesto
ernesto
hello thanks for your response no I have not next on the list!
piranha-bro2
Hero member
- Location
- Melbourne
It's probably under-responding in the other gears as well - just that it will be more obvious something ain't right in 5th with the highest load. Plenty of places to start looking but as Ernesto says a strobe is probably a good first stop. Then compression test and a full service check if it's advancing OK to 40 deg at revs.
Ernesto
Hero member
- Location
- Hamburg, Germany
Depending on the chosen curve the Sachse-Ignition advances
between 30° and 40°.
Ernesto
Hero member
- Location
- Hamburg, Germany
The latter, Paul...
piranha-bro2
Hero member
- Location
- Melbourne
Aplogies - missed the Sachse ignition bit - yes, curves will differ.
Whatcha moanin' Paul?
If a person cannot cope with an electronic system, he'll be truely overwelmed by points, these have far more idiosyncrancies to deal with than electronic systems.
This points/electronics debate is completely pointless (pun intended) and has become very boring. Electronic systems are at least as reliable as points, and they do NOT wear. If the wiring loom and charging circuit of the bike is kept in good order, they far outperform any points system... for longer and without further maintenance.
Maybe you should just try out a decently set up 750 with an electronic system, Paul? My customers have always noticed a big improvement after such a mod.
Why Sachse offers a 30° full advance curve for the 750 is beyond me. It would need something like 16:1 CR, alcohol/nitrous fuel and triple sparks to get anywhere near there... simply stupid. Due to the inefficient stone-age design of the 750 inlet tracts and combustion chamber, full advance will be somewhere between 36 and 40° BTDC, depending on cams and CR. I have not yet come across one running properly on less than 36°. This is NOT an ignition issue, solely fuelling and combustion related. Cooking-variety 750s invariably run excellently on 40° full advance.
A bike running out of steam in top gear will most probably have other issues than only incorrect ignition timing.
piet
Yes Piet.
However, statistically speaking, one can only see that problems with point ignitions, apart from not finding new points, hardly ever crop up on this forum.
There could of course be several reasons for this.
Discuss. You have 2 hours.
Paul
The Sock
Hero member
- Location
- London, England
Maybe the sort of technophobe who wants to cling to points doesn't tend to have much truck with "that there t'interweb", computers and such.
Bein' as how these are newfangled things, which work well for "other people".
Just sayin'.
Bein' as how these are newfangled things, which work well for "other people".
Just sayin'.
piranha-bro2
Hero member
- Location
- Melbourne
It's just a bizarre concept that elec ignition is a recipe for trouble. How many of the BILLIONS of cars and motos put on the roads in the last 40 years still have points? Manufacturers the world over must be persisting with electronic ignition systems because they are so incredibly unreliable and they want their product to break down as publicly and as often as possible ...
You ought to open a breakdown company or a breakdown insurance.
Lucrative businesses.
Paul
According to that Hamish, we're all technophobes. We should be riding electric scooters.
It's just that the get you home clause on my bike insurance will only take the bike 20 kilometres to the nearest Laverda dealer, so I prefer things that I can fix myself.
When I'm touring, which is quite often, I always carry a complete spare points plate and a coil. I could of course carry an electronic ignition box of tricks.
Paul
Tippie
Hero member
- Location
- Dr?bak, Norway
Which would be no different at all. How much do they sting you for that fantastic insurance?
€100 for 8 bikes actually running.
With all the cash I save, I'll be buying ignition boxes.
Paul
The most common fault of modern vehicles is battery failure (german automobile club ADAC just published recovery results from last year). This is 99.5% due to negligence and will stop any vehicle, be it sourcing it's sparks through analog points or digitally. Actual ignition system/motor management failures do not show in their statistics, probably not enough to appear amoungst the top 100 failures. Dead batteries, flat tyres and un-usable spares (if at all present) on P2... exemplefies the mindset of modern day motorists!
Sure, points will work until eternity. It's just, what do you expect from them? All mechanical bits will wear, maybe not such a problem for you and me Paul, we won't need to deal with it for much longer, but for the younger ones expecting optimal power and reliability from our old clunkers, well, they're fucked.
We're dealing with components that are now around 50 years old, most of them have seen the odometer go around at least twice. Even when brand new, machining tolerances made exact timing quite difficult, by now it's almost impossible. Generations of back-yard bodgers haven't made things easier. I have not been able to set ignition timing properly with points for ages without needing to deviate from the specified gap on one set. Then there's the range through which the timing is advanced, with the worn mechanical centrifugal device this can be best described as erratic. This stuff was never meant to be in use for over 50 years, let alone perform at a level that is now required and expected.
Do you really, really want to prove a point, Paul? Take your 750 on the Autobahn and go flat out. See if you make it to the next exit... most points-equipped bikes will have burnt either a valve or holed a piston by then. Only meticuously well set up points (and carbs) will allow this (and it applies not only to Laverdas!!), but that's not saying you can repeat it a month later without having to fiddle with them yet again. Modern digital electronic systems will remain as set for years and will run reliably as long as the remainder of the ignition-related electric system of the bike is kept in half-decent condition. Most problems with electronic systems turn out to be user-related, ie, home-made issues, be it through lack of understanding or sheer ignorance. Much the same for points actually, only with the additional mechanical wear and tear issues that the average Joe fails to recognize.
So, you carry a complete spare ignition system? All I take along, at most, is a spare "magic eye" aka the optical trigger for the DMC. Swapped out in minutes and thanks to a previously applied marking, no need for complete new adjustment as long as I don't go 10/10s afterwards. This has been part of my minimalistic tool bag (which would fit in my trouser pocket) for decades, the only time I have been stranded was when I left it at home... but, thankfully, Keith Nairn was able to come to rescue me with a magic eye he robbed from his own RGS. The same components are used for the 750, MkII and 120° triples, making sourcing and keeping spares cheap'n'easy.
piet
Sure, points will work until eternity. It's just, what do you expect from them? All mechanical bits will wear, maybe not such a problem for you and me Paul, we won't need to deal with it for much longer, but for the younger ones expecting optimal power and reliability from our old clunkers, well, they're fucked.
We're dealing with components that are now around 50 years old, most of them have seen the odometer go around at least twice. Even when brand new, machining tolerances made exact timing quite difficult, by now it's almost impossible. Generations of back-yard bodgers haven't made things easier. I have not been able to set ignition timing properly with points for ages without needing to deviate from the specified gap on one set. Then there's the range through which the timing is advanced, with the worn mechanical centrifugal device this can be best described as erratic. This stuff was never meant to be in use for over 50 years, let alone perform at a level that is now required and expected.
Do you really, really want to prove a point, Paul? Take your 750 on the Autobahn and go flat out. See if you make it to the next exit... most points-equipped bikes will have burnt either a valve or holed a piston by then. Only meticuously well set up points (and carbs) will allow this (and it applies not only to Laverdas!!), but that's not saying you can repeat it a month later without having to fiddle with them yet again. Modern digital electronic systems will remain as set for years and will run reliably as long as the remainder of the ignition-related electric system of the bike is kept in half-decent condition. Most problems with electronic systems turn out to be user-related, ie, home-made issues, be it through lack of understanding or sheer ignorance. Much the same for points actually, only with the additional mechanical wear and tear issues that the average Joe fails to recognize.
So, you carry a complete spare ignition system? All I take along, at most, is a spare "magic eye" aka the optical trigger for the DMC. Swapped out in minutes and thanks to a previously applied marking, no need for complete new adjustment as long as I don't go 10/10s afterwards. This has been part of my minimalistic tool bag (which would fit in my trouser pocket) for decades, the only time I have been stranded was when I left it at home... but, thankfully, Keith Nairn was able to come to rescue me with a magic eye he robbed from his own RGS. The same components are used for the 750, MkII and 120° triples, making sourcing and keeping spares cheap'n'easy.
piet
The same can be said of modern motorcyclists. As the French saying goes, it's feeding caviar to pigs.
As for battery failures, you know very well that the ideal ignition system is the magneto. No battery.
They're fucked anyway, because they're going to break our old Laverdas because they have no idea of what an old internal combustion engine without an oil filter demands.
The very rare times I take the Autobahn, I am flat out, at 130 km/h which is for the moment the legal limit. My old carcass can't put up with the wind pressure for long anyhow. Most of our Laverda motorcycles, twins, triples, 500s, were blown up nearly new by youngsters who would ride them like Kleenex motorcycles: blow your nose in them and throw them away. Their Laverda would blow up whereas the pile of junk from Messrs Kawasaki, Suzuki or Honda would keep on going, leading Joe public to think that they were good motorcycles. Laverda got a bad reputation with the public as soon as it stopped racing 750s, and winning.
Same here Piet, without the magic eye. The only time I've been stranded on a Laverda since my first in 81, was a dead coil.
Magnetos rule.
Paul