I think you will find the exciter coil is the one just right of bottom center. That coil is physically small for the DC-DC converter approach. I still feel the voltage you are seeing from that winding is low, but cannot say for certain without reverse-engineering the entire system. It would at least be possible to rewind that coil by hand.
You could further test the ignition coil by heating it and observing the resistance change in the secondary winding.
You could also use your peak detector on the primary side of the ignition coil (but reverse polarity so the positive lead is grounded. The CDI capacitor discharges a negative-going pulse into the ignition coil.) It may be difficult to analyze those results, however.
There's not much more testing you can do without an oscilloscope.
Yes. I'm working on a lengthy write-up titled Improving 40mm Marzocchi Forks, but briefly...
GasGas says to use an SAE 7.5 oil in their Marzocchi forks. Unfortunately, there is a lot of variability between manufacturers in what they consider to be a 7.5 weight oil. I strongly suggest that you select fork oil based on its kinematic viscosity (which is measured in centiStokes) instead of by its rated weight. Peter Verdone has a fabulous table of many readily available fork oils along with their kinematic viscosity. See: https://www.peterverdone.com/archive/lowspeed.htm
Forks run cool, so all I care about is the kinematic viscosity at 40 degrees C.
In the US, the recommended fluid isGolden Spectro Cartridge Fork Fluid 125/150 (which is 26.1 cSt @ 40C). Personally, I feel that is too heavy and am using Maxima 85/150 (which is 15.9 cSt @ 40C).
It's possible the system does not operate as I had guessed. Perhaps the CDI utilizes a DC-DC converter? That would explain the relatively low voltage observed. Can you post a picture of your stator?
Exciter coil (10,8-13,2 Ohm/25°C): actual value 12,6 Ohm/19°C
As coils were heated, resistance slowly increased from 12,6 Ohm to 14,2 Ohm.
Compliments on your testing and reporting skills!
That resistance indicates a fairly robust wire diameter that would be less likely to fail than a much finer wire. The results you saw when heating the coil also indicate it is not likely to be the problem. You would need special test equipment and "ring" the coil in order to test for a few shorted turns.
cascade1imp quoted a reading of 20 - 30 VAC (no peak reading adapter) on the exciter coil when kicking. (Was this with the CDI connected, or not?) If no one is willing to build your peak reading adapter (with a 4.7 uF capacitor) and test their bike, this may be the best information you will get.
One of the drawbacks of trying to quantify the AC voltage produced by a motorcycle stator coil is that the waveform is nothing like a sinusoid, and different meters will measure it differently.
Although be aware that different values of the resistor and capacitor (and the input impedance of the meter itself) can give rise to different readings as well.
That's all I can contribute for a while, as I'm off to do a trials now.
What is the ohms range given in the manual and what does your exciter coil read?
Excellent question! And, at what temperature is it being measured?
Although resistance readings can help find a defective coil, they can't guarantee proper operation.
I expect your exciter coil will be comprised of many turns of fairly fine wire. Even a few shorted turns will cause it not to work properly, yet the resistance reading will be essentially unchanged.
The fact that your pickup coil was inoperable also may be a clue to damage by water.
Another test is to measure the resistance of the suspect coil while heating it with something like a hair dryer. Copper wire has a positive temperature coefficient of ~0.4% per degree C. You should see the coil's resistance increase gradually as you heat it. If, however, the resistance drops suddenly, this indicates a problem.
The two power coils in the alternator are "floating" so there's nothing to ground (therefore corrosion of the alternator cover bolts can't cause your problem).
The G/W wire from the ignition pulse generator connecting internal to the CDI ground wire is not necessarily a problem (and would be unlikely to cause the intermittent symptoms you describe).
I have no experience with this particular model, and I'm not sure about your nomenclature.
But... for the winding that goes to the CDI (not to the voltage regulator) I would expect to see closer to 100V while kicking. How are you measuring the "peak" voltage?
The output of that winding is dependent on RPM. I would suggest "motoring" the engine with an electric drill via the flywheel nut (you may have to get creative with a socket/adapter etc.) I generally do this with the head off, but just removing the spark plug may give you a clue.
P.S. you've done a good job troubleshooting so far!
Also because of the 2mm bigger bore they make the bottom end power very smooth and clean.
I would take issue with the reasoning behind that statement. Generally, a smaller bore will produce a higher air velocity thorough the carb which will help low-rpm response.
If there is a low-rpm improvement with the Keihin / OKO it's because they are flat-slide-carbs (versus the Dellorto which uses a round slide). The smaller volume under the flat slide makes it respond quicker because fuel is pulled through the need jet quicker.
A larger bore has the potential to flow more air for high-rpm use. On just bore size alone, a 28mm carb provides 16% more area than a 26mm carb. However, additionally, a flat-slide carb will flow more air than the same size round-slide carb.
Except for turning, I don't use the clutch much. Do you have any suggestions on developing that skill?
One finger, and one finger only, always on the clutch lever. Ride a gear higher than you normally would. This will force you to quickly develop the skill.
At some point in the bike's life did you top-up the fluid and then later replace the pads? Trials reservoirs are small -- maybe there was not enough room for thermal expansion of the fluid.
In any event, I would check for pad wear and evidence of them binding in the caliper; exercise the piston travel with the pads removed and clean everything; perform a fluid change.
The short answer is, no. I'm not a chemist and most of my reading on the topic has been on the combustion side.
However, there is a criticism of ethanol I've been meaning to add and will take this opportunity to do so. It comes fromthe SAE book Alcohol as Motor Fuels (PT-19).
Alcohol is a good solvent for gums and many other materials which deposit from gasoline. A dirty gasoline fuel system is a source of trouble when filled with an alcohol-gasoline blend, since dirt is commonly loosened and plugs the system at critical points.
Have you played with the ignition timing? Generally, advancing ignition timing will help bottom-end power/response at the expense of high-RPM power and possible detonation. I also find that a combustion chamber with minimal squish clearance and a sharper blend radius (both of which increase turbulence and therefore rate of combustion) will create a more explosive "hit."
I must be missing the point but what is the issue.
For me, it's mostly about consistency of use. None of my other bikes auto-retract (or at least they did not do so for long). Every other bike I've owned provided an easy means to defeat their auto-retract mechanism.
P.S. I removed the inner spring thinking that might do the trick, but no luck. Not sure what that inner spring is supposed to accomplish -- maybe just Honda's "belt and suspenders" approach?
Marzocchi Shock Seals
in Gas Gas
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I fixed some typos. Did that make it any clearer?