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Still chasing this issue on my 98 TW200. Today it started right up and rode well. Occasionally at a stop sign it would stall out but it would fire right back up. After about 15 minutes of riding it bogged out and wouldn't restart so I pushed it home. When the bike died the battery was dead, when I started riding it the battery had a charge in it. When I got home I gave it a shot of starting fluid and it fired right up until it burned it away then it shut back off. It seems like a fueling issue but my carb was professionally rebuilt already. Then today I swapped on a brand new carb and it's still having the same issue. Petcock was flowing, I pulled the line and it had a steady flow to it. I've been chasing this problem for a while and don't know where to go from here. It really seems like it's a fueling issue since the ether made it fire but I think it's weak spark and the ether can ignite it when the gasoline can't any ideas?
 

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Eliminate the tank not venting problem first !

Check the threads below
 

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This seems like it could be an electrical issue. Possibly the coil-pack? I have had similar experiences with a lawn tractor that had a crack in the coil pack. It started and ran fine for a bit-then once it heated up-the coil pack which had a small hairline crack in it expanded and the spark was lost-leading to the same symptoms you are having. Once it cooled down, it would start and run fine and then repeat the problem all over.
 

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Discussion Starter #6
This seems like it could be an electrical issue. Possibly the coil-pack? I have had similar experiences with a lawn tractor that had a crack in the coil pack. It started and ran fine for a bit-then once it heated up-the coil pack which had a small hairline crack in it expanded and the spark was lost-leading to the same symptoms you are having. Once it cooled down, it would start and run fine and then repeat the problem all over.
Tried a new coil, no dice. Only thing I didn't try was a new plug boot, the extra coil I had was missing the boot. I'm starting to think it's the CDI, i've read 2 threads with similar problems and that's what it turned out to be but I don't really want to waste several hundred dollars and find out it wasn't the CDI
 

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Still chasing this issue on my 98 TW200. Today it started right up and rode well. Occasionally at a stop sign it would stall out but it would fire right back up. After about 15 minutes of riding it bogged out and wouldn't restart so I pushed it home. When the bike died the battery was dead, when I started riding it the battery had a charge in it. When I got home I gave it a shot of starting fluid and it fired right up until it burned it away then it shut back off. It seems like a fueling issue but my carb was professionally rebuilt already. Then today I swapped on a brand new carb and it's still having the same issue. Petcock was flowing, I pulled the line and it had a steady flow to it. I've been chasing this problem for a while and don't know where to go from here. It really seems like it's a fueling issue since the ether made it fire but I think it's weak spark and the ether can ignite it when the gasoline can't any ideas?
I offer this information as an additional possible cause and in know way want you to disregard any of the information others have provided you already. Just another possibility.

The tricky thing here is your battery goes dead. May be a clue but I'm not sure. Maybe a weaker battery and with you trying to start it after stalling it drains the battery of it's remaining electrons.

One possibility is the Pulser Coil also known as a pickup coil located with the stator under the left engine side cover. On one of my TW's I had similar symptoms as you. After riding for 15-20 minutes the engine would stall out. Sometimes I could get it to start but as this engine stalling reoccurred, the less likely it was to restart. With the engine sitting overnight I could get it to start again but the engine would stall after 15-20 minutes again.

I watched a troubleshooting video about pickup coil's which indicated it was hard to test the Pulser coil when the engine was warmed up. The Pulser coil wires would test OK when cold but not hot/warm. Unfortunately, the only way to really be able to tell is to replace the Pulser coil. Parts swapping diagnostics isn't the best if you don't have donor bike parts on hand. I had an old TW and swapped the Pulser coil which cured my problem. A 1998 Pulser Coil is about $83.00 at https://www.rockymountainatvmc.com/oem-schematic/2.

Because the symptoms are so similar to a carburetor problem, I veered off into cleaning and even swapping out the carb with a known good one before I realized it wasn't a carb issue but and electronic issue.

Good luck and hope you get it figured out.
 

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I recently bought an xt225, and it also did this. It turned out to be loose rust in the tank that was clogging the petcock screen. Not saying that's what it is, but as others have mentioned, you just have to start eliminating possibilities to narrow down the cause.

I like admiral's suggestion, too.
 

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When my '87 had a bad CDI, it wouldn't run well when it was warm. When I first started the bike on a cold morning, it would run good for a few minutes and then would start to miss and run really crappy, until it finally died. Then I couldn't get it to run well again until the CDI cooled (either the next morning, or by putting it in the freezer). The symptoms you're experiencing don't sound exactly like this.
 

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If the battery goes dead while riding that's a clue. There's some sort of problem with the charging system. Stator or rectifier.

I doubt it's a fuel issue. Sounds electrical. Electrical components when they go bad often fail when they get hot, I've seen stators that work OK cool, but their output gradually fades to nil once the engine reaches operating temperature, Or, like 10-15 minutes.

Your CDI box needs energy to generate sparks. The trigger coil is just that, a "trigger" it does not generate the energy itself for the spark. That comes from the battery, from the rectifier, from the stator. It'll run off the battery for a while- not very long, the headlight and ignition will suck the little TW battery flat within 15-20 minutes), and with nothing recharging it, your bike in effect runs out of electrons and dies.

Charge the battery and fire the bike up. Put a voltmeter across the battery with the engine at fast idle. Should read 14-14.4v or so. I'm guessing yours will read <12.5, meaning the bike is draining the battery, not charging it.
 

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Discussion Starter #11
I'm almost positive it's not the petcock. When it died I pulled the fuel hose off and it had a solid stream. I've actually just replaced both the stator and rectifier and nothing changed. Maybe just had a bad battery but it started the bike up fine and then died. The pulser coil is a good thought, I've ordered one and will try that next. Bike is driving me crazy at this point I don't care how much I spend to get it fixed I need to know what the issue is
 

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If you've already replaced the stator and rectifier (and ensured the bike is actually charging the battery) I'd turn my attention to checking the ignition coil, which can be easily tested with an ohmmeter. Primary resistance is between the two small wires, which is generally like 3-5 ohms or so. Not zero, not drastically higher. Secondary resistance is from the + input small wire to the plug wire. That's usually more like 10k ohms. The shop manual has specs for both, that's just off the cuff.

If you've ruled everything else out then I'd be looking at the CDI. I have seen ones that fail as they warm up from use. Generally leave the most expensive/complex for last, since there's not really a good way to test CDIs. The manual just says "replace with known good" if you suspect it has an issue.
 

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Cooling the CDI down and then immediately using it is a fairly good and easy test. If the bike runs good for the first couple minutes after cool-down, and then starts running crappy after the CDI warms up, that's a pretty good indicator. It takes only a minute to unplug and reinstall the CDI for this test.
 

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If you've already replaced the stator and rectifier (and ensured the bike is actually charging the battery) I'd turn my attention to checking the ignition coil, which can be easily tested with an ohmmeter. Primary resistance is between the two small wires, which is generally like 3-5 ohms or so. Not zero, not drastically higher. Secondary resistance is from the + input small wire to the plug wire. That's usually more like 10k ohms. The shop manual has specs for both, that's just off the cuff.

If you've ruled everything else out then I'd be looking at the CDI. I have seen ones that fail as they warm up from use. Generally leave the most expensive/complex for last, since there's not really a good way to test CDIs. The manual just says "replace with known good" if you suspect it has an issue.
The battery and charging system has nothing to do with the spark. They are two separate systems. A weak battery will not crank fast enough to make a spark from the ignition system other than that has nothing to do with spark.
 
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