1978rm125 wrote:
... need to TIME it!...
Here's some generic advice.
First clean points and set the "gap" between them BEFORE addressing the ignition timing.
The "bulb" or "ohm meter" method of timing (called "static" timing) gives a decent ball-park adjustment, but a strobe-type timing light ("dynamic" timing) allows actually seeing the timing marks line up while the engine is running, and actually watching the advancer unit in action as it forwards and retards the timing while blipping the throttle.
If same or similar to 900's, here's some detail ---
The points set itself is held to a small back plate by two screws. The screw at the heel end of the points serves as a pivot. The screw at the contacts end of the points is through a slotted hole which allows the points
gap to be set. The gap setting is the prescribed maximum distance between the points when the fiber heel is atop the highest rise on the cam surface. An accurate gap requires clean smooth unpitted contact surfaces. Usually there's a small felt tab touching the cam surface. A drop of oil on the felt lubes the fiber heel moving against the cam surface so as to help keep the fiber heel from wearing out so fast. Gradual wearing away of the fiber heel reduces the gap, so the gap must be periodically re-adjusted. The gap alone has some influence on the subsequent actual advancement or retarding of the ignition timing.
The small back plate (to which the points are attached) attaches by two screws through slotted holes to the large round mounting plate. The two slots in the smaller backing plate allow the points to be precisely set in a position whereby they open exactly at the prescribed moment before the piston reaches the top of its stroke (top dead center), which is where the
F mark on the advancer unit should align with the permanent mark on the engine case.
Ignore the
T mark as the T mark is
not used in ignition timing. Recall here that opening of the points is what triggers the coil to fire the sparkplug. This alignment of the F mark with the engine case mark is viewed at low idle speed rpm with a strobe light (dynamic timing). In static timing (engine off), the points should open just as the F mark reaches alignment with the engine case mark. This is determined by hand turning the crank and using an ohmmeter or light bulb connection to show when the points first begin to open. These two slots usually allow enough back and forth movement to accurately set the ignition timing by aligning the marks. Remember, the gap has already been set and will remain the same while the ignition timing (advance/retard) is being adjusted by moving the points back and forth in the two slotted holes.
The
large round mounting plate attaches by three screws through slotted holes to the engine case. If the previously mentioned two slots on the smaller backing plate fail to allow enough movement either way to align the F mark and engine case mark, then the large round mounting plate may itself be moved within its three slotted holes to a better position whereby the smaller backing plate may then be moved in its slotted holes to achieve the desired ignition timing position (alignment of F mark and engine case mark).
By the numbers ---
1st -- Adjust gap -- Turn crankshaft clockwise using wrench to widest points opening and adjust gap to specs (KZ900 is 0.3-0.4mm or .012-.016 inch). Slightly loosen the two base screws which allows movement to open or close gap, then retighten after setting gap at its widest position when the heel is resting on the highest part of the cam. At this stage nothing but the gap has been adjusted. But this is important because proper gap does affect accuracy of the subsequent timing procedure. And all other screws have so far remained tight.
2nd -- Set Timing -- The points set has two mounting screws in two slotted holes with pry slots which can be used with strobe light (after slightly loosening the two mounting screws) to align the F mark with the permanent engine case timing mark. But if the adjusting plate doesn't travel far enough to allow correct adjustment, then loosen the three large round mounting plate screws and move the mounting plate as necessary -- and is this doesn't suffice, something is likely wrong in the assembly, as it did not arrive in such condition from the factory.
3rd -- Tighten and recheck --Tighten all screws and recheck timing with strobe light.
Also, check to assure proper operation of the advancer unit. If removed for cleaning and lubing, be sure the cam unit is replaced correctly and not 180 degrees off.
Also good to have a fan blowing onto the running engine cylinder while setting the timing.
Good Luck!
