stumpnthqldd23

Thanks Tetel.

Thanks for everyones input. See attached images of points/advancer/Stator/flywheel. Does anyone know if the TL ignition should have some sort of a suppressor or resistor in the plug cap/lead? Could someone compare the the magnet placement vs timing marks on the flywheel? The ignition stator is on the bottom in both the picture and on the bike. the old man honda link with the part number information is very helpful, thank you so much!

Both these photos are from the taken from in front of the bike.

This was the best resource for me to compare parts http://www.cmsnl.com/honda-tl125s-trials-usa_model1106/partslist/?model_q=tl125s

The left side where the drum brake is runs up against the fork leg while the right side has a spacer fitted. I will add photos in a minute.

Earthing the secondary coil shows no improvement.I did have to drill 2 small holes through the metal of the coil in order to bolt it on the original mounting. (it was just a universal coil)

Thanks for everyones time and input. I do certainly have a mixture of engine bits. When we got the bike going from a fresh rebuild and complete restoration including stripping and painting everything and installing all lights and wiring new and from scratch, we never got the magneto ignition to work correctly and put it down to a faulty original secondary coil. We quickly converted it to battery ignition run straight from the battery and using the original points to switch the earth to the coil. This puts too much load on the battery system (had to charge it every week) and I wanted to convert it back to magneto for reliability reasons. I have been riding the bike to work and back for over 6 months with this setup. The timing of the points was left and I fitted the new Secondary coil and new condenser (from Sammy Miller), new spark plug cap (non Resistor) and modified the wiring for the ignition all back to original. (ac primary coil output goes straight to the secondary coil/condenser/points) Bike started fine but when I rode it, it would loose spark all together or back fire through the carby/cough etc as soon as you asked it to work hard. (Give it a small hill to climb, or open the throttle) If I nursed it, I could get it to rev right up as normal. The coil base is not earthed except through the frame and this will be a spot to check as with the battery ignition it would not need an earth at the frame. (Kids are asleep right now so it'll have to wait a few hours) The engine is TL125E The head is a 383 CB125 J/N. I'm pretty sure the cam itself is from the TL as I don't remember having more than one of these spare. The points base and auto advance parts have 355K stamped on them. I have followed the TL manual for setting the points timing. In Australia the CT is very common farm bike, my Dad has repaired hundreds of them and has a mass of parts, the 185 version of these engines is also used in junior speedway solos, and my Dad and friends have also worked on hundreds of these. This is why I have ended up with a mix and match of parts as most parts are interchangeable, or at least fit but possibly this is why we are having ignition issues. We just used the best of the bits. It did have new piston/little end bearing/valves/springs/seats/valve inlet grind/cam chain. Basically the whole top end is brand new. The other auto advance I have is 356STD and now that you have drawn attention to it, it is mechanically different. Counter weights look smaller. After online research of how magneto ignition systems work, the timing of the magnets with the primary coil is very important. The flywheel I have looks like it has 4 magnets, it has 2 dowels fitted also. If the auto advance system was wrong, would the battery ignition still work ok? If the bike will rev up does that too therefore eliminate the auto advance? The opening duration of the points could be causing issues though, but then why does it backfire like the ignition has a mind of its own? I will attached a couple of photos that may help and will try a direct earth on the secondary coil asap. Sorry if we are getting lost in some of the technical terms here.

Hi Max, I do have the TL engine, with a CB125 Head fitted with all new valves, springs, cam chain, piston and top end all done. The gearing is definately not CB or CT. First 3 gears are all close together and used up before 25 KM/H. I dug through the rest of my left over bits and talked with my Dad and we do think that the stator cover is off a more modern CT125 (maybe mid ninties) with a TL stator fitter for the ignition only. I have taken off the cover and checked out where exactly all the parts are. I am using winding in the top section to drive the battery charging setup, and I have fitted another ignition stator from what I believe to be a TL to the lower side and I have the issues. I'm currently searching for more information on timing setup for the ignition in case it is different from what it should be for the battery ignition. Other thoughts are whether the primary coils could be not lined up correctly with the magnets in the flywheel? I completely done away with the idea of running 6V lights off the original primary coil as done originally in the TL for fear of road worthy issues here in Australia. It has all 12V lights, horn, indicators, number plate lights, brake lights all wired like you would find in any more modern bike.

Hi Bigmike, Thanks for the reply. The new ignition coil comes with a new condenser, but I did swap in the condenser from the battery ignition setup with no change in the symptoms.

Hi Everyone, I have a TL125S lovingly restored. It has been running on battery ignition with the original points as I converted it to battery with all lights to commute to work. We had issues with the magneto style original ignition at the time of build and just went with the battery ignition option temporarily. I recently got a new ignition coil and plastic side panels to complete the restoration and after fitting the coil/condensor I found I still have ignition dramas. The bike is very easy to start, has enough spark to hurt my foot when the timing was set a little aggressive, but as soon as you load it up it miss fires, completely looses spark and back fires through the carby. The stator side cover was on the bike when I road it 15 odd years ago before the thing got boxed up till last year. This side cover is not a Tl125.It looks identical from the outside but the actual primary coils are different. It has 4 wires coming out of it. Black - White - Maybe Blue - Maybe green. from research I believe the magneto style ignition was a little unique for its age and not many had it. The stator cover seems the same as quite a few models, specifically the cb125 but I have read that the flywheel on the Tl is different. Even after hours of research and looking through many wiring diagrams I cannot find anything with 4 wires out of the stators, only ever 3! I may have to resort to have the ignition stator re-wound or repaired as I see nothing else that could cause this issue, but I'm unsure of whether the stator coil goes on the top side or bottom side of the cover? Other trouble shooting I've read online here says there should be almost no resistance with the points closed (I have about 0.4-0.8 Ohms) and very high resistance with the points open (this i do not have, about 1 - 1.2 Ohm) But looking at the wiring diagram there is no way that the resistance could be high as you have both coils in parallel with the points open? (I am an Electronic Technician by trade) The blue wire is currently being used for charging the battery system with a plain single rectifier. It produces around 3-4.5 amps dependant on revs and this balances out nicely for the headlight draw and LED lights for tail/break/indicators. Any help on identifying the current stator set would be a great start, and if anyone could specifically tell me whether the ignition stator belongs on the top/bottom of the cover, that would also help out. As others have mentioned, the amount of interest the old honda bike generates any where I take it is unbelievable. I never though anyone would be remotely interested in it! I'm having major withdrawal for not being able to commute to work! Kind Regards, Graham. Brisbane - Australia