It was a long winter and the thought of riding your RL250 in sub-zero temperatures and 15 inches of snow was way down on the to-do list. You remember that you were going to drain the RL250 fuel tank and carburetor but things got crazy and you didn't get around to it. Did you turn the petcock to 'Off' or did you leave it on?...oh, well. There would surely be a warm weekend soon when you could roll the RL out of storage and drain the old gas but those holidays were really busy. Then, you think that five months have passed already so what's another few weeks. You decide to wait until it warms up a bit before messing with the bike.
Then, that weekend finally arrives. No snow. The family is at the movies. A light jacket will keep you warm enough if you stay out of the wind. It's time. You have to move the snow blower before you have enough room to roll the RL outside. A quick look around reveals nothing out of the ordinary. The petcock is 'OFF'. Good man. You turn the petcock to 'ON' and watch the fuel run through the filter and into the carburetor. The fuel stops flowing. That's good. Choke on, kick once. Kick once more and your RL250 comes to life after a long winter's sleep. Just like it always does.
I've heard many variations of this scenario over the years of owners and their RL250s but always with that common thread of two to three kicks and away it goes. The unsung hero of these stories, I believe, is Suzuki's Pointless Electronic Ignition (P.E.I.) system. A poor choice for a name but a terrific system.
Why is this important to our story above? Because easier starting is one of the benefits of Capacitor Discharge Ignition (CDI) systems. The spark can be advanced electronically for starting and the voltage generated for the spark is greater than from a points system.
As far as the TS250 platform, the first P.E.I. system appeared on serial number TS250-23216, which places it toward the end of the 1971 TS250R model year. The 1972 TS250J model began with serial number TS250-27153. Of note, then, is that Suzuki thought so much of their new ignition system that they introduced it mid-year.
It replaced the ubiquitous points system with its inherent wear and corrosion issues. In retrospect, and with modern CDI systems to compare, the points systems had little to recommend them. Oil and humidity were their enemies. The cam lobe contact block would wear closing the point gap and changing ignition dwell and timing. A condenser had to be connected across the contacts to diminish, but not eliminate, arching. On the plus side, the systems were simple and everyone understood and could work on them. That was fortunate since the points systems needed constant care.
The P.E.I. system is just the opposite. There is nothing to physically wear out. The Owner's Manuals for the 1974 RL250L and the 1975 RL250M said the following under the section titled 'Ignition Timing':
"Ignition timing is adjusted at the factory and should normally require not adjustment (sic). However, if the stator is removed or tampered with, adjustment may be necessary."
Suzuki's perspective was that they set it up correctly during the manufacturing process and, as long as the owner didn't tamper with it, the system required no routine maintenance. After 40 years and counting, these systems still don't need maintenance. Amazing.
So, how do you set the ignition timing on an RL250? Well, first off, congratulations on getting the flywheel off. That task itself has been known to make grown men cry. Since you probably didn't go to all this trouble just to tinker with the ignition system, you must have had the engine apart and now it's time to, well,...time the thing. Right up there with the P.E.I. system as a feat of engineering is the ease in which the system is set.
You've got the center cases together and the next task is to install the stator plate. The stator plate is a round aluminum disk with two coils installed; the bigger Exciter coil creates the voltage for the spark and the smaller Pulsar coil that provides the spark trigger. It is installed to the left center case with three 5mm Phillips head screws (use #3 Phillips screwdriver) with large flat washers. The holes for the three screws are slotted allowing the stator to rotate a few degrees. Position the stator against the center case with the coils at about 10:00. Thread the two lower screws and leave loose. Don't install the top screw yet.
Referring back to the 'Ignition Timing' sections of the Owner's Manuals, the following sentence sums it up:
"In this case the top mounting screw should be aligned with the mark stamped on the stator plate."
This is only slightly misleading, because you can't see the 'mark' with the screw and flat washer installed. So, what they mean is to align the top mounting screw 'hole' with the 'mark stamped on the stator plate'.
Refer to the two images of the stator plate installation. The image on the left is the plate with arrows pointing to the three stator plate screws. The image on the right shows the top screw removed and one arrow pointing to the 'mark'. The mark is a line cast into the stator plate that bisects the slot. The goal, according to Suzuki, is to rotate the stator plate until the mark bisects the screw hole. Once accomplished, the two lower screws may be tightened to hold the setting. Install the top screw and you're done.
That is, at least, what Suzuki wants you to know about setting the timing. Frankly, I don't know why they didn't mention that big pointy thing that looks like an arrow that is cast into the left center case just above the stator plate that just happens to bisect the top screw hole and, if the mark is aligned with that pointy arrow thing, the same timing setting is achieved with less guesswork. But, what do I know?
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Matrix Motor Sport