Dead 1975 TY175B

[Starky]

OK fellas I need some help BEFORE I start pulling things apart.

My Problem - The TY died on the weekend while I was sitting idlying waiting at the start of a section. No bang, splutter or anything. It was running fine until then. Some of the previously ridden sections did have water to the top of the engine cases.

The TY has electronic ignition. I changed to a brand new plug. Still no spark. Heaps of fuel comimg through. Push start down hill, still no start. I have opened the ignition case and probably about 20ml of water ran out. It could have come in through the breather pipe (I will put a longer/higher one on now) or it may have come in through the gasket even though it was tight and fairly well sealed. The case itself has a minor crack which I beleive is water tight but maybe not?

I thought electronic ignitions could cope with a little water?

What am I looking for?

[FM350]

OE electronic ignitions can put up with water (but good idea to avoid if possible), but some after market systems dont seem to have insulation on the source and trigger coils thats designed to cope with water, and failure is not unknown. Try drying the stator plate out, using indirect heat, and then try it again. If that doesnt work then contact the manufacturer of the ignition, and see if they can provide some resistance values you can check out.

[Starky]

OK long story, short. The TY 175 now has a new electronic ignition installed (I had a spare one here for another project) and working like brand new and maybe pulls a bit better then before. I have sent the troublsome ignition away for further tests and repair.

Todays question is, 'Inside the ingnition case there is only a coil and flywheel all the other electronic bits are up under the tank, there are no moving parts under the flywheel therefore does the case breather pipe or hole even need to be used?' Can I close them over?

[FM350]

If you have a poorly made electronic ignition that has failed after a small amount of water gets in, you need to get the cracked cover repaired, properly seal the cover to crankcases, and remove it after very wet trials and blow out any water with an airline. You can block the vent pipe if you choose, but this will mean any condensation inside the case stays there, and may affect your replacement ignition. Personally I would refit the points, as if they are serviced and maintained properly running will be as good or better than aftermarket AC/CDI systems, and they can be easily and cheaply repaired if anything goes wrong.

[Starky]

Yes, I have replaced the side case, but I don't think it was that as you can't blow air through the crack and it will not leak water when filled from the inside. I had a short breather pipe dangling down the rear of the motor and the trial section had water over the top of the cases. I think the water came in the breather pipe as it was all under water. I now have a breather pipe that goes right up to under the fuel tank cap in the tank tunnel. I thought of the condensation issue that is why I did replace the breather pipe.

I also agree that any future ingition fault will see the old system go back in but with all new bits. I would not have used the electronic system this time but I already had it.

Thanks, confirms my thinking.

[Tee-Why]

Starky, by way of chance, was the bike kicked over at any stage prior without the plug lead attached to the plug? ie the plug able to ground spark? Simple enough done if turning over in shed when working on it also. Maybe after the plug fouled initially.
I ask this because this is a known cause of failure with earlier Beta electronic ignition failures. This has been determined by others, that design does not like open circuit, and the high CDI discharge doesnt seem to have a diode for blocking or discharge path to short to prevent failure.

Also if its the very same type of Electronic Ignition from John Cane in the UK that I have also, I did notice the CDI is infact a Yamaha unit, I would not be surprised if the unit is off a current model AG100. If the coils (primary and trigger) are ok, the AG100 CDI is available off the shelf in OZ as a replacement. The ignition curve for the AG100 is the same as described on John Cane's ignition for the TY175, I have found this myself somewhere at sometime, as I was going to make my own.

EDIT - you say you have another electronic ignition? Did you check the resistance between coils and compare between the sets and to the backing plate?

[FM350]

Beta ignitions were still failing in 2010..............Dougie had one go on him in the SSDT! Seems weird that this problem still doesnt appear to have been sorted?

[Starky]

Hi Subanator,
I did a copy and paste of your post to answer your questions in red.

Starky, by way of chance, was the bike kicked over at any stage prior without the plug lead attached to the plug? ie the plug able to ground spark? Simple enough done if turning over in shed when working on it also. Maybe after the plug fouled initially. Not to my knowledge and at that stage I had done all the work on the bike.

I ask this because this is a known cause of failure with earlier Beta electronic ignition failures. This has been determined by others, that design does not like open circuit, and the high CDI discharge doesn't seem to have a diode for blocking or discharge path to short to prevent failure. I will keep this in mind in future. I should also add that both the mechanic and I were getting intermittent spark? I could get it to run for about five minutes and then it would die but this was about two days after the trial. I gave up on it as I don't have the tools or knowledge and handed it over to the mechanic who did his apprenticeship on these TYs.

Also if its the very same type of Electronic Ignition from John Cane in the UK that I have also, I did notice the CDI is infact a Yamaha unit, I would not be surprised if the unit is off a current model AG100. If the coils (primary and trigger) are ok, the AG100 CDI is available off the shelf in OZ as a replacement. The ignition curve for the AG100 is the same as described on John Cane's ignition for the TY175, I have found this myself somewhere at sometime, as I was going to make my own. Both CDI ignition systems are from John Cane. EDIT - you say you have another electronic ignition? Did you check the resistance between coils and compare between the sets and to the backing plate? The mechanic did check the resistance and they were the same between both units to within 10 units of each other. He was very critical of the way the windings were done with cable ties and then covered with resin. I have very little mechanical knowledge and less on electronics so this is the best I can explain it.

[Tee-Why]

Ok, then maybe the problem is possible to do with connectors or a bad earth at the CDI unit under the tank. The method illustrated by John Cane web site photos, has the CDI in the frame gusset. If the bolt used to mount CDI and also for the bond for the earth ground to frame, make sure the connection is to bare metal of the frame, no corrosion etc. I know this can be off putting for a newly painted or powdercoated frame!
Also recrimp all connectors with decent crimp pliers and pull apart the push in type connectors, again check no corrosion.

A failure in the coils will be hard to prove, may need an insulation tester (higher voltage used to see if a breakdown in insulation has occurred, heed warning to low voltage coils here). A multimeter wont pick this up, maybe a good one will. But a little current in the insulation tester will breakover the failure point, proving a problem. Hope this helps, maybe too much info!

[FM350]

The most likely reason any one of the often poorly made aftermarket electronic ignition systems are likely to fail is due to the coils being hand wound, often by people working from garden sheds. Hand winding means it is difficult/impossible to make certain the windings are uniform, and this leads to overheating of the windings in certain areas, that results in breakdown of the insulation, and either complete failure or intermittent failure of the coil in question. Failures on Beta are probably linked directly to same thing, and all this comes about due to the want to save a few pennys on production costs. For a reliable system to fit the TY look at adapting OE Yamaha parts to fit, which will work better and will also be far more reliable than the shoddy aftermarket types.