copemech Posted October 25, 2009 Report Share Posted October 25, 2009 Gday, That's the easy way to tell Jon, 3 wires for a Hall sensor. I was thinking this morning that another reason Hall sensors are not common in dirt bikes is because they need a stable supply voltage to run which is not easily obtained in your dirtbike. Unless it has a battery. Of course Honda have worked around that with the Montys, but I hazard a guess that they still use reluctors for triggering. And definately a hall sensor Cope! What was that system from?Cheers, Stork That is the standard single map for Sherco, virtually identicle to the one listed for Rev 3 except for direction of rotation. Seems the dual map versions of the stator vary little, as the switch input is just a ground path for the black box! Quote Link to comment Share on other sites More sharing options...
stork955 Posted October 25, 2009 Report Share Posted October 25, 2009 Interesting - A Sherco system! It seems I'm learning a bit too! The stator wouldn't vary for single or dual maps as that is all done in the CDI. Grounding something is probably changing the way the wave shaping comparitor bit does its job to get the different curve. That stuff is getting over my head... Cheers, Stork. Quote Link to comment Share on other sites More sharing options...
copemech Posted October 29, 2009 Report Share Posted October 29, 2009 Interesting - A Sherco system! It seems I'm learning a bit too! The stator wouldn't vary for single or dual maps as that is all done in the CDI. Grounding something is probably changing the way the wave shaping comparitor bit does its job to get the different curve. That stuff is getting over my head...Cheers, Stork. Well, I think you see what may be going on here with what appear to be dual single wire magnetic analogue pick ups. There may indeed be a A/D conversion in the black box, but nothing even resembling a digital hall effect(3 wire) here, and I cannot even fathom how they can claim that otherwise. Yet it is what it is, and applies to Beta and Sherco , although I cannot tell you the current Beta system because I have not looked! I can only suspect that the dual pick up systam must be rate based(rpm) between the two sensors to establish a proper curve within the range. My impression is that the older Ducati system as used on both Sherco and Beta was a single pickup design. All hypothetical as I have run no actual tests! Anyone got a spare ocillisiscope to get a few actual readings? Quote Link to comment Share on other sites More sharing options...
02-apr Posted October 29, 2009 Report Share Posted October 29, 2009 Knowing from the old points days that getting the timing absolutely correct (adjusted every two events on my 348) makes an appreciable difference I wanted to check my Beta by strobe as I wasn't happy with its running. This of course requires timing marks and knowledge of the mm BTDC figure to make those marks using a gauge in order to check the system (would you trust a Beta system to be well enough made as to be firing at the correct advance?). The best I could get out of the guys in the workshop at Beta UK was that the standard setting of screws in the middle of the slot "seemed to be about right" but that nobody knew the actual timing setting, even the works guys. Does anyone have access to information on what the correct figure should be? Quote Link to comment Share on other sites More sharing options...
matt_urban Posted October 29, 2009 Author Report Share Posted October 29, 2009 the guys at lampkins told me that head bolts and barrels bolts should just be done up the same and torqueing dont matter so i wouldent trust them with a timing figure i will try retard it a bit and leave it at that as long as its less snappy i will be happy Quote Link to comment Share on other sites More sharing options...
copemech Posted October 30, 2009 Report Share Posted October 30, 2009 Knowing from the old points days that getting the timing absolutely correct (adjusted every two events on my 348) makes an appreciable difference I wanted to check my Beta by strobe as I wasn't happy with its running. This of course requires timing marks and knowledge of the mm BTDC figure to make those marks using a gauge in order to check the system (would you trust a Beta system to be well enough made as to be firing at the correct advance?).The best I could get out of the guys in the workshop at Beta UK was that the standard setting of screws in the middle of the slot "seemed to be about right" but that nobody knew the actual timing setting, even the works guys. Does anyone have access to information on what the correct figure should be? I understand your referance to the older bikes, yet on the modern bikes, the timing really does not vary once set. The factory settings are generally a tradeoff between performance and ridability, and from my experience it gets much more into personal pref from that point. With all my tinkering, I have not reall tried to put numbers to it but once, and found it mostly irrelitive. Referance marks on the stator plate are much more relative. Add one might find that he could advance the timing just a bit(2-3mm) or slow it (6-7mm) within a limited working range that suits you. My experience on the Sherco(very similar to the Bets in most respects) suggests a change of 2 or so mm on the plate (wich roughly equate into degrees of angle) are required to find a signifigant(noticable) change in the performance. So lets just say that you have normally about 10mm within the stator plate range to play with, or roughly 10 degrees of angle in 2mm increments. Neverming mm BTDC, as this can just get too confusing and way too sensitive as you come close to TC and you will dirve your self nuts using that method. If you want a slower bike that is more managable or a quicker bike that kicks back and stalls more easily, it is up to you to decide, as I do not know of a perfect number in degrees or mm that will satisfy you or your riding! Pick your own poison, but that should give you a much better idea! Quote Link to comment Share on other sites More sharing options...
02-apr Posted October 30, 2009 Report Share Posted October 30, 2009 (edited) Thanks Copemech but you miss my point. I know that modern systems do not move once set, in theory at least, but, and this is where my reference came in, it is possible to tell the difference between fairly small differences in setting in how cleanly the bike runs and I always found the recommended setting best (given a standard carb carefully set up). If there's one thing I hate it's a two stroke that does not run cleanly all through the rev range but particularly at the bottom. Before experimenting it really should be ascertained that the bike is set to the manufacturer's recommended figure and this could easily be done with a dial gauge in the old days. Without a figure in mm btdc or degrees this can not be checked by marking the casings for strobe use on modern systems. We are completely reliant on the production tolerances of the ignition system and its mountings. There are few Beta owners, or former Beta owners especially, on here who would praise the Beta ignition as the finest example of high quality manufacturing. In the 21st century we should not have to mess about going back and forth from a vaguely defined point in order to find an optimum setting. I'm all for anyone tweaking to suit their preference, to me it's part of what trials is about, but the manufacturers should be treating us as being a bit more intelligent and capable and providing basic information. Edited October 30, 2009 by 2/4 Quote Link to comment Share on other sites More sharing options...
stork955 Posted October 30, 2009 Report Share Posted October 30, 2009 Gday, I have seen an online tool on the net somewhere that calculates degrees to mm BTDC. You need to know the rod length IIRC and some other data but it would be workable. My Techno has a timing mark on the flywheel so it gives me a reference point to work from. The other way to do it is to use an advancing light and make your own TDC mark which is easy to do with a piston stopping tool. This is what I generally do especially when Im in a hurry on a paying job. 2/4 -As far as points go if you need to adjust them every 2 trials I have to ask are you lubricating the rubbing block? On the Hall sensor thing, the sensor itself isn't digital as I understand it. It does need a nominal current and allows an "external" current flow through itself when in the magnetic field. The sensors do have wave shaping built in to give a nice square wave result, which can then be used with either digital or anologue systems. It would work fine with your standard basic CDI however it still needs that constant 5 volts or whatever to run. The dual pickup system is as you say Cope, totally RPM based - it uses variations in sensor output voltages (Reluctors increase output with speed) to give a change in advance. The system (as I understand it) splits the output from the advanced trigger into 2 waves, one that is held constant, and the other that is allowed to change. The outputs of both are summed together to give a resulting change in retard amount. God only knows how this would happen with a Hall sensor... maybe someone can explain this for me! Cheers, Stork Quote Link to comment Share on other sites More sharing options...
copemech Posted October 31, 2009 Report Share Posted October 31, 2009 Thanks Copemech but you miss my point. I know that modern systems do not move once set, in theory at least, but, and this is where my reference came in, it is possible to tell the difference between fairly small differences in setting in how cleanly the bike runs and I always found the recommended setting best (given a standard carb carefully set up). If there's one thing I hate it's a two stroke that does not run cleanly all through the rev range but particularly at the bottom. Before experimenting it really should be ascertained that the bike is set to the manufacturer's recommended figure and this could easily be done with a dial gauge in the old days. Without a figure in mm btdc or degrees this can not be checked by marking the casings for strobe use on modern systems. We are completely reliant on the production tolerances of the ignition system and its mountings. There are few Beta owners, or former Beta owners especially, on here who would praise the Beta ignition as the finest example of high quality manufacturing. In the 21st century we should not have to mess about going back and forth from a vaguely defined point in order to find an optimum setting. I'm all for anyone tweaking to suit their preference, to me it's part of what trials is about, but the manufacturers should be treating us as being a bit more intelligent and capable and providing basic information. I wish that were the case, but yet once again I do understand totally what you are stating here and have no total solution. I kinda figure things to vary a bit as things go, cause (on my sherco) I figure the alignment mark on the stator plate was put there by Leonelli, and the case was referenced by sherco, who knows? Mfg varience? And although Sherco do or did list a spec in MM btdc, I am now shy to use that as a reference. Quote Link to comment Share on other sites More sharing options...
jse Posted October 31, 2009 Report Share Posted October 31, 2009 My Techno has a timing mark on the flywheel so it gives me a reference point to work from. The other way to do it is to use an advancing light and make your own TDC mark which is easy to do with a piston stopping tool. This is what I generally do especially when Im in a hurry on a paying job. Me too. If I'm messing with ignition setttings (or cam settings), I use the "positive stop" method to find TDC for that specific engine to give me an absolute starting point. As I remember, it was developed many years ago by a guy named Ed Iskenderian, who was a master cam grinder for the flathead Ford V8 engines we were running in our race cars at the time. We needed to find TDC accurately to be able to degree in the cam during installation. How it's done is to attach a degree wheel to the engine (I use a small wheel with several strong magnets attached so it easily attaches to the flywheel and mine is old enough to have "AJS" inscribed on it.... and make a pointer. Use a piston stop tool (looks a little like a sparkplug with a long, large projected tip, the one I made has a tip adjustable for depth) that contacts the piston crown a few degrees before TDC. Rotate the crank carefully until it stops when the piston touches the stop, mark the wheel, rotate the wheel back the other way till it stops, mark the wheel. Absolute TDC will be exactly in the middle of those marks. Say the distance is 41 degrees between the two marks, TDC will be 20.5 degrees from either one. Jon Quote Link to comment Share on other sites More sharing options...
02-apr Posted October 31, 2009 Report Share Posted October 31, 2009 Me too. If I'm messing with ignition setttings (or cam settings), I use the "positive stop" method to find TDC for that specific engine to give me an absolute starting point. As I remember, it was developed many years ago by a guy named Ed Iskenderian, who was a master cam grinder for the flathead Ford V8 engines we were running in our race cars at the time. We needed to find TDC accurately to be able to degree in the cam during installationJon Agreed that finding TDC is dead easy but without an advance figure it is impossible to check other timing marks and experience tells me that they are not necessarily correct. If the "works" mechanics haven't a clue on this then what hope does the average owner have. Establishing the advance currently set would just be a case of trial and error with strobe markings but of limited use without a reference figure. Let's face it, somebody designed the system for the bike so why can't we be told what the design figure is - if I could set things absolutely accurately thirty years ago why should I not be allowed to do so now? Quote Link to comment Share on other sites More sharing options...
stork955 Posted October 31, 2009 Report Share Posted October 31, 2009 Gday, they probably dont think we want to play with our timing! - Its always been a bit neglected on bikes anyway. Most people go straight for the carb and possibly dont know how much is actually gained from timing adjustments... My TDC tool is made from an old plug (I have 3 in fact in different sizes)with the centre knocked out, and tapped for a bolt with a rounded end. Easy to make for anyone really. It gives a nice reference point so you can advance it up till it pings and back it off a couple of degrees. Cheers, Stork Quote Link to comment Share on other sites More sharing options...
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