OK i bare my neck and throw myself to the wolves. I'm trying to check the timing on my '81 R100RT. Which cylinder is #1 the right or left? I have a new MotoElectric bean can and ignition module installed, but the advanced timing mark (Z) won't come to the mark on the block. I want to make sure the timing light sensor is on the correct side and not throwing my timing reading off. I checked it with the sensor on the right cylinder. Rick Jones thinks the ignition module is at fault and is sending a replacement.
Thank you for the quick reply. I run the RPMs up to 4000+ and the advance mark isn't ever close. Waiting for my new module.
Thanks again. rick
Scott is correct.
Typically, EI initial installation settings are just that: Initial Settings. The ignition timing is NOT set; it is only close enough to get the engine to run. (Do not ride the bike with this setting.) Once the engine is running you can employ a strobe timing lamp and finish the job. This includes connecting the trigger lead to either spark plug lead, and then cranking the bike. Having a box fan in front of the engine helps !
Once the engine is running, you loosen the ignition sensor plate mounting screws and rotate the sensor plate clockwise or counter-clockwise to make the "F" mark center in the timing window at the prescribed RPM. It is very important that the installer (that's you) use the manufacturer's prescribed RPM (or higher) to be sure that the timing has been set at "Full Advance". Tighten the mounting screws and then re-check the setting with the strobe lamp.
Due to the distance between the trigger plate and the strobe lamp hole, this job is sometimes accomplished easier with 2 people; one to look in the hole and one to get burned on the exhaust pipe ! Especially for the novice tuner with a low blister count. Having a box fan in front of the engine helps !
And did I say that having a box fan in front of the engine helps ?
😉
PS. Your EI instructions should come with a resistance spec on the ignition coils; either as individual coils, or for the pair. This is very important for proper performance of the EI. Once a coil is disconnected, the resistance can be accurately measured with a common digital Ohm meter. This is really important if you suspect after-market or even updated Bosch coils have been mounted. This takes about 3 minutes to do. Better safe than sorry.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Did do the initial timing with two people, one on the timing light, a non adjustable style light, and one on the can. The idle timing was slightly advanced but made the adjustment at the can and now right on the mark. The full advance mark was not lining up. Oh yeah i did have a fan blowing on the front of the engine. Easily forgotten. When i get my new EI unit i'll check the ohm readings on the plug wires. Although they were replaced (NGK style) last year. Coils are still originals.
The coils are Bosch They are a metal canister style with brown heads on them. I did check the brown heads when i replaced the spark plug wires. I've read Oak's articles and other threads about the cracking in these areas and causing headaches.
Were you planning on "posing" with your BMW, or actually riding somewhere ??? 😛
The "Slow" ignition setting is ONLY good if you are using the stock points and stock ignition cam. No EI manufacturer guarantees that their unit advances the exact same number of degrees as the stock ignition cam. Why ? Because the fuel has drastically changed since your bike was new. And so in order to keep pace, the ignition advance curves as well as the total amount of advance has drastically changed too.
Since you probably DON'T have the advance/retard specs of your new EI, the only option left to you is to set the ignition timing at FULL ADVANCE using the "Fast" mark. This because, that's where the timing will occur while you're actually riding the bike. And since that's also where the most heat is created, so it's important to optimize the timing at that speed to prevent engine damage.
Full retard on the other hand is only used for cranking, idling and posing. Not only is idle timing used a mere fraction of the "run time", but the criticality on this timing position is probably 10X less than full advance. So forget timing on the "Slow" mark, that means absolutely nothing now.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Coils are still originals.
I have 2 sets on "original" Bosch coils on my bench right now. Both sets are from Airhead BMWs. One set measures 2.7 Ohms per coil, the other set measures closer to 8 Ohms per coil.
My EI manufacturer suggests best performance at a TOTAL resistance of 6 Ohms for both coils. I'll be using the 2.7 Ohm set.
So again I ask you, what is your resistance requirement for coils and what do your coils measure ? This is not an academic exercise. Nor am I writing this to merely get my post count higher. This is real stuff you got to do if your bike is going to run its best.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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