Honda FL250 Odyssey Lighting Coil Mod For Charging Battery

The Odyssey that we worked on had the Goki Electric Starting kit added, probably many years previously. Electric starters need a battery, and the FL250 had nothing setup to charge the battery needed for powering the electric starter...so we had to figure out how to add that.

 

The Odyssey 250 is actually an AC system, including an AC ignition coil and AC lighting. Since the original did not have a battery, there was no need to convert any of that energy to DC. Unfortunately, this also led the engineers to save some wire and use the frame as the 2nd leg of the AC circuit. But....that single-wire AC made it quite tricky to make a charging system for the battery setup. 

Scouring internet forums and consulting various Honda wiring diagrams, we decided that the best solution for good charging of the battery is to use the lighting coil as the charging circuit, but the coil needs to be modified so it has 2 wires instead of only the existing single wire AC.  That way, the power from the lighting coil can be run through a voltage rectifier and converted into DC for the battery.

This shows where the original lighting coil winding was attached to the magneto plate. Remove this screw and cut off the copper wire from the terminal beneath.

This is the copper wire that is the end of the lighting coil winding, ready to be soldered to a wire and run out of the engine case. Remember to use heat shrink or another insulator to prevent the wire from touching anything else in the case.

Here you can see the wire soldered and wrapped with heatshrink so that it is no longer in continuity with any metal from the engine. This way it can be run, with the other existing lighting coil wire, into a 4-wire DC voltage rectifier (2 AC wires in, a power and ground DC out). We used one from a Honda CB350 and got a charging voltage of 13.7-13.8v, enough to recharge the battery after using the electric start.

Here you see the modified coil on the magneto plate, about to be bolted back into the engine. The lighting coil is the copper colored coil, the other large coil is for the igntion and the small coil is the pickup for the electronic ignition. 

One other thing to keep in mind: we kept the original AC taillight, so that the taillight is on when the Odyssey is running and turns off with the engine (since there is no keyswitch), To do this, simply make a 3-way connection in the wiring from the lighting coil and have one branch go to the light and the other to the rectifier. Hope this helps, good luck!

Honda FL250 Odyssey Variator Rebuild

 

Here are some photos of our recent rebuild of this 1982 Honda FL250 Odyssesy variator pulley, an early version of the style used on many modern scooters and even cars these days. Photos of this process seem pretty scarce out there so hopefully this helps!

The old variator assembly after removing the outer bell housing - notice the roller arms are flopping because the springs for these two rollers were broken - only 1 functional roller was left! Also, you do need an especially long puller to remove the variator from the driveshaft - the one we used was about 6" long

Each variator roller is held in by an M6 bolt with an M10 head, which is also held by a locking tab. We were able to use a large flathead screwdriver inserted through the center of the roller to bend it back and access the locking tab and bolt to remove them.

New rollers installed! We assembled each one completely with both springs, then levered each spring forward onto the roller arm. We used a spring puller to pull the end up, then a flathead behind the spring to hold it while using another flathead to slide it over onto the roller where it holds in place. Notice how the new rollers are holding firmly agains the central spindle now. When the engine is turning, centrifugal force has to overcome the springs on the rollers and thus spread the cones farther apart, so the drive belt falls lower - this is how it changes the gear ratio as you accelerate :)

Everything back together! And with the bell housing cleaned off you can actually see the manufacturers stamp on the retaining band. These were originally made in the USA by Salisbury for Honda.

We're Back! Unveiling Our New Shop in Millvale

 After a long and winding road, and a year working with Nice Bikes in Bloomfield, we're thrilled to announce that we're opening an expanded shop at a former cabinetry and glass block warehouse in Millvale.  For the next few months we will be open by appointment only as we continue to build out the shop and prepare for riding season, so please get in touch if you have a vintage ride that needs work and we can put you on the schedule.

Here is the address for our new shop:  531 Evergreen Avenue, Pittsburgh PA 15209

You can reach us by phone at 412.294.8666 or email slagheapcycles@gmail.com 

See what's going on in the shop through our Instagram @slagheapcycles