I have a '76 R 75/7 and having ignition timing issues at the moment. I was contemplating installing the Dyna 3 electronic ignition system (still uses the centrifugal advance unit). I believe that there is an issue with the CAU itself, as the timing is too far advanced and there is no further room to adjust/ retard the ignition. Facing the choice of purchasing a new CAU ( about $250 ), hoping this is the fix, and purchasing the Dyna 3 ( about $200). I found elsewhere on this forum, a system called Powerdynamo which renews the charging and ignition system in one kit. does anyone have advice for the timing issue and/or any experience with an aftermarket kit such as the Powerdynamo?
It sounds like all your trouble might just be the points. There are a lot of junk points out there. Why do you think there is trouble with the advance? No experience with the Powerdynomo. IMO, there are reasons why bikes don't have setups like that anymore. Mainly their issues.
You don't mention how many miles on this machine. Always may be related because you are ditching whole systems that are meant to last well beyond 100,000 miles. The advance unit can be taken apart and cleaned. It does get lubed in several places and the cam tip is lubed, where the advance unit rotates. This rotation is the mechanical advance. There are two small springs that BMW does sell (these two springs are the only part of the advance unit sold separately so don't loose any of the other tiny parts like the fiber washers). Depending on how much you ride it's not unusual to remove, clean and adjust the advance unit once a year. (the new springs deal is not every year but many of these machines do have the original springs still on them) If you are starting out or even if you have a little experience with mechanics these machines have a regular program for tuning them up. It starts with setting the valves and ends with balancing the carbs. In between these two parts is setting the ignition timing and this will often include installing new points. There is more info in your manual about doing this stuff. Try this before wholesale replacement. You don't say where you are. Is there a local dealer where you buy parts? Not all dealers are Airhead friendly but they should all have the correct points by now. The correct ignition points come in a box labeled "Norris" . You can mail order parts and the correct parts are always available at Ted Porter's Beemer Shop; http://www.beemershop.com/ There are other popular places to order parts. Ted is one of the best.
The power dynamo kits are aimed at the earlier bikes pre 1970 and have the likely disadvantage of only producing a claimed 190W, which is less than the 280W produced by your bike. The Boyer electronic ignition replaces both the points and the mechanical advance and retard unit. It is fairly cheap and available in the US. It is also easy to fit as long as you remember to set the timing by using a timing light at full advance. Make sure if you go down the electronic ignition route to buy a system from someone like Boyer or Dyna who have been in the business for a long time, a couple of years ago there was a system made by a small German company called Omega, that became all the rage with US based airhead riders, however the company stopped making the systems and people were left in the lurch if they had problems with the system. Other good suppliers are Sachse or Silent Hektik. (expensive)
Do you have a manual? If not, I recommend getting one. In the manual there is a section describing static timing. For static timing a clip and 12V light bulb need to be wired together. After getting the static timing set, a timing light and the tachometer can be used to make fine adjustments. Checking and replacing the points is a good suggestion. Norris still makes quality points. I recently cleaned, lubricated and replace the springs in my CAU. Now, the idle return is quicker and consistent. But, the starting and normal running (>3K rpm) is unchanged. Ride the bike at over 3000 RPM's so the timing is always fully advanced, thus the CAU operation is not critical, and the battery gets charged. If you can't get the bike started, the static timing is likely incorrect or the points are bad (but, it could be wires or coils if they are original). There is an advance unit grease, sold by BOSCH and a points grease. The two are distinct and separate. Other than sticking so the advance is too high at idle or will not fully advance ~ 3k RPM, there is nothing to go wrong with the CAU - and even a 'defective' unit won't stop the bike from running. Other than requiring accessing the points and the potential to burn yourself, the points ignition system on an airhead is very simple and reliable - even when it doesn't work as designed it still works. But, if you want to spend money on an electronic unit please don't let me dissuade you. Good luck!
I run the Dyna III on my '78 R 100/7 but also carry my original points and related parts to convert back to stock if I have to. The Dyna has been OK for ten years so far.
Many riders like the Dyna III. It can compensate for a ghost timing mark and it eliminates the points and condenser which are regularly replaced. So over time it should pay for itself. But many of us think a Booster is more to our liking. The Booster keeps the points and point plate in place and adds a module to handle the current going through the coils. The points then are still used but become a simple switch that isn't carrying all the current for the system This cause less wear on the points and they can last practically forever. Having the Booster also seems to provide for a stronger spark. The real advantage is that I don't have to carry the OEM parts to use should there be a problem with the electronics of the Booster. The OEM system is still in place and all that is needed is the moving of a couple of wires to eliminate the Booster and revert to the OEM system. I might add also that a Booster is much cheaper than a Dyna III. There are other brands and other options. There's even a kit that cost half what the Dyna Booster costs; The kit of course means you have to assemble it but if you are game it is made by a company called Velleman. If you have trouble finding it just ask and I'll dig it up. Charlie
That was my experience (I think others here have mentioned it too)...the lousy Chinese points have a rubbing block that's too high. I didn't have quick access to another set of points so I had to make the slots in the backing plate longer to get the timing set.
The Booster is usually mounted on a frame down tube at the front of the bike, next to the front engine cover. But the wires are long enough to mount it almost any where. Directions say to put it where the air will hit it but I have seen them mounted under the gas tank and riders report no problems with over heating. The directions are a bit confusing. The condenser is not in the circuit with the Booster hooked up but it can stay in place. Should it ever be needed someday it is still there.
Thanks for all the help...where do i start... I looked at CAU as a potential issue b/c timing at idle was already at full advance and the points backing plate would not allow for the timing to be further retarded. The CAU lobes had some play when not rotating (i.e. loose springs) so I figured this was the most likely culprit; I did not consider faulty points to be a potential as well. There are 32,000 miles on this machine. When I discovered the timing issue and blamed the CAU, I called the local dealer, 441 Cycle, in Ft Lauderdale, FL and was told to expect $250 for new and a hefty wait time as there didn't seem to be stock in US or Germany. The points look almost new; this possibly lending argument to them being recently replaced with poor aftermarket quality. Many thanks for the beemershop link; I was in need of a online source. Does anyone know af any Airhead friendly shops in South East Florida?? I do have a Haynes manual. I was originally checking the timing via the static method using a multi-meter when it seemed that the charge was applied close to the full advance mark. Questioning my understanding of what was described as the correct timing characteristics, i decided to use an inductive timing light to get a better idea while the machine was running....then came full advance at idle, etc. I currently have the Dyna Ignition Booster wired in (definitely noticed a difference once installed) and a new 3ohm, dual post coil from dyna as well. I was leaning toward staying with the points for simplicity and reliability, though these factors are fast becoming my reason for favoring an electronic ignition. This machine is a daily rider for me when I'm in town (I travel for work, sometimes months at a time) so streamlining tuning sessions is a draw as well. I dont tour with this bike (yet at least) so the worry of ignition failure from aftermarket electronic ignition systems while 1000's of miles away from home doesn't seem too daunting. Bottom line, it seems... I will be looking into sourcing new springs for the CAU and new points, if I decide to stay more traditional. Hopefully the points, not the CAU, are to blame for timing headache. ...Or...I am going to research the Boyer system further and make a decision between it and the Dyna III. Thanks to all the comments and suggestions. Resources like this are truely PRICELESS!!
A good mail-order source for Airhead-specific parts is Hucky's Spare Parts in Vero Beach: http://bmwhucky.com/ Hans Lowe knows his parts and BMWs. The advance unit itself probably doesn't need replacement (the cost of that part has been outrageous since the 1970's) unless it's really rusted and abused. Cleaning, new springs and lubrication will do wonders (be warned, those teeny-tiny springs as $12 each). There is a special grease for the advance unit, but I get by with using ignition points lubricant (needed, don't substitute). One caution: keep a light touch in snugging that 10mm wrench-size nut that holds the advance unit on. The threaded end of the camshaft has been know to snap off. A Dyna Booster is a good item. Takes the electrical wear away from the points, though the gap has to be adjusted periodically since the rubbing block still wears. --Bill
Having the Booster is a plus. Keep it. You still have to properly gap the points to get the ignition to be properly timed. When using a feeler gauge to gap the points make sure it is clean, don't get grease or oil, even oil from your hands, on the feeler gauge where it is transferred to the points. Setting the gap is a pain because the advance unit has to be in place and it blocks access just when it opens the points. There is a nice tool that you place on the cam shaft to replace the advance unit and have much better access to the adjustment. Of course like all the other tools these days it costs too much money but I do believe this one is worth it. There are two ways to effect timing other than the the rotation of the point plate via the slots you mention. 1st is the dwell angle. This is the point gap you set with the feeler gauge. A slightly tighter gap will be a little bit less advance and a slightly wider gap will be more advance. The dwell or point gap affects timing. Timing does not affect dwell. If you are new to doing these mechanic things or even if you have been around for years it may have been many years since you used an ordinary feeler gauge. 2nd is the advance unit on the cam tip. It is held in place by the small nut that fits the 10mm wrench (careful with this thread on the tip of the cam. over tightening and breaking this tip off is very common) When you remove the advance unit for cleaning you should notice that it is located on the tip by a D shape. This provides proper orientation but they are almost always loose. So even with the advance unit on the tip of the cam and engauged with the D shape it can be rotated several degrees. Usually at least 2 or 3 degrees rotation is available and sometimes more. So before the 10mm nut is tightened hold the advance unit all the way retarded to gain some relief at the points plate slots. Finally it is not uncommon to take a small round file to the slots and lengthen them a little. If you must resort to this don't feel too bad but the other two methods should be tried first and they should work. You mention the timing is advanced full at idle but you don't mention that when the rpm is raised it goes beyond full advance. This sounds like your real problem at the moment is the cam tip the advance unit is on needs cleaning and lube. This can be lubed with a light oil or light grease. There is a special grease needed for the advance cam where the points rubbing block rubs. It is "Distributor Grease". Search this here at Advrider. The original Bosch Grease has not been available for several years. There are acceptable aftermarket brands you can use. This is a heavy grease, so it doesn't get flung off onto the points.
I love the way you guys up North speak. "module with built-in 'ramp' " I think some will like one and some will like the other. I've also heard electronic advance fans say that the electronic function is just better. When I had one several years ago I kept advancing the timing till one day it rattled going down the road. I'm hard of hearing and I couldn't hear the preignition till it got severe. That was one of those mounted on the crank types (back when they were the new hottest thing). I also had a Dyna III that I blew up. Was totally my fault too. Maybe the thing is I don't get along with them so I'm just better off keeping what works for me. The Boyer seems the most popular these days. Has certain advantages over the Dyna III I think
I have a dyna 3 on my 1976 r/75, works great, no more points,( today's points are not like the old ones) the dyna is a solid unit.