yamaha tri moto 200 dies when warm

[1984R250]

this is an issue i have had with my old tri moto 200. it would start up and run good, but when it got warm, it would die. i replaced the coil, but that didnt fix it, and i can not find a replacement cdi for this unit. its the single 4 pin connector going to the stator with the other single wires coming from the cdi box. is it possible to use one of the cdi's with the two 4 pin connectors on it with redoing the connections? i can pick those up all day cheap, but i dont know how to wire it up, if that will even work. i have not touched my tri moto in a couple years now since it started having this problem, but i want to get it ironed out and running right. i did try to start it this summer, but the pull rope broke and thats where i left off with it. there is no visible leaks around the cylinder for there to be a head gasket leak, the carb has been replaced, although its a chinese clone so not the best, but it did run with it before. i mainly want to rule out the cdi by replacing it, but i'll need to adapt a different cdi to it it seems. if anyone can help in that regard, it would be MUCH appreciated!

[ATC King]

You can't mix and match CDIs. The ignition timing has to be correct for the engine and the CDI controls that. Incorrect ignition timing can damage an engine.

As for the rest of it, because it's been sitting for so long, all needs a thorough going over. That includes looking in the intake through the frame and making sure there's no critter nests. Whil inspecting, you'll look at the electrical connectors. Are they clean and tight or does it look like one has been hot before, brown and burned looking. A loose connector can get hot and open the circuit.

[1984R250]

You can't mix and match CDIs. The ignition timing has to be correct for the engine and the CDI controls that. Incorrect ignition timing can damage an engine.

As for the rest of it, because it's been sitting for so long, all needs a thorough going over. That includes looking in the intake through the frame and making sure there's no critter nests. Whil inspecting, you'll look at the electrical connectors. Are they clean and tight or does it look like one has been hot before, brown and burned looking. A loose connector can get hot and open the circuit.

i was looking at the two connector cdi from the moto4 200, which is the exact same engine....

[gimmeamidget]

I had a Yamaha big wheel 200 that would do the same. Mine ended up being the stator and I believe it’s a common problem with Yamahas. I would swap stators or get rid of it and buy Hondas instead.

[ATC King]

i was looking at the two connector cdi from the moto4 200, which is the exact same engine....

What year and model YTM200 do you have? There was some with shaft drive and electric start, others were chain drive and recoil start.

I looked at the CDI for a Moto4 and by their size, they're probably DC powered, needs a battery. That won't work on the AC only YTM200. I tried verifying it by looking for a Moto4 wiring diagram, but didn't find what I was looking for.

A DC CDI is larger because of the extra electronics in it. When you've looked at and compared an AC CDI and DC CDI, it's a pretty good guess which one is which.

To your issue, the YTM has no mechanical advance, it's all electronic. That's why it's so important to use a correct CDI. The Honda 185/200 engines have a mechanical advance on the camshaft, so the CDI circuity is minimal; basic. All advance on the Honda engines is controlled mechanically, much like a distributor on an older car, which are also driven by the camshaft.

Also, 'exact same engine' isn't correct unless it's the exact same vehicle. Yamaha's 200cc engine made it into several vehicles and they won't all have the same advance curve. Weight, gearing, intended use, compression ratio, base timing (electric start vs kick/recoil) camshaft specs all can change and that will change the needed timing. That's similar to the Honda 200cc engine that was in ATCs, dirt bikes, dual sports, ATVs, and maybe even a road bike (US market or elsewhere). An ATC200S doesn't have the 'exact same engine' as an XR200R or ATC200X. The top end parts swap, but there's differences in compression ratio and the camshaft. That's where the mechanical advance gives them an advantage.Even though the engines are similar, they're different enough to require their own advance curves, but that can be done with the same CDI but different advance springs and/or weights.

Into the meat of it, fuel quality, ambient and engine temp, humidity, barometric pressure, elevation, engine load, all play a role in ignition timing. The OEM YTM200 CDI has an ignition curve that walks the safe line for all of those parameters.

I'm talking about generic advance curves, sub-optimal, not tuned for that engine used in specific conditions. Power is left on the table to be safe for a larger distribution area.

What I'm getting at is you'll need a CDI for that machine. If you want to swap things up, you'll need to research it. That means looking up, if available, advance curves for each engine the CDI was meant for. That's not the end of it though, because there's other factors. Really, if want to go that route, you'll need things like a degree wheel, a way to attach it to the crank, and a timing light to verify.

There may have been someone who done a CDI swap but didn't gather the proper information to verify it. Lazy, cheap, and not a reliable source of information, but that's what's typical with what you can find on the internet. Good enough types, the ones who oo on those who strive to get the details. Details? It didn't blow up, so that's all the proof you need types.

When it comes to replacing old CDIs on machines that were abandoned by the manufacturer, modern programmable ones aren't much, if any more expensive than OEM (which isn't available). I know the last available CDIs for a Yamaha BW200 were expensive, I think over $200. That's squarely in the aftermarket programmable CDI range now.


Edit: 11/19/2024

That's a longer post, but don't forget to check everything else over, including the fuel cap vent. It's easy to get tunnel vision while diagnosing problems.