If the bike is misfiring or backfiring, take the bike to a Yamaha-literate mechanic and have them tune the air intake and exhaust to specifications. If it’s misfiring, the same could be true of the air intake. The first thing to look into on a bike that’s popping like crazy is the exhaust system, especially if you bought the bike used and it came equipped with an aftermarket system. Here are some possible reasons for the engine misfiring problem: Like all engines, if the engine-tuning of the Yamaha D125 is out-of-whack, the motor might ‘misfire’ or ‘backfire.’ Engine Misfire Symptoms: Stalling isn’t the only issue that Yamaha DT 125 owners have had to rectify, If you’re out of this range, you’ve got a bad coil. The ideal resistance range is 6,000 to 12,500 ohms.

Measure the resistance within the small primary wire connections with an ohmmeter.

The ideal range would be 0.5 to 3 ohms if you got something else, the coils bad.

Measure the resistance between the coil connections with an ohmmeter.

With a wrench, detach the small primary wires.

Detach the spark plugs from the ignition coil with your hands.Hit the kill switch to turn off the bike’s ignition.If you’ve checked the spark plugs and they’re not bad, the next step is to safely test the ignition coil to see if it’s the violator here. The ignition coil increases the low voltage your battery cranks into the high voltage required to spark the spark plug and ignite the combustion. The other common culprit for a stalling engine is a bad ignition coil. Fortunately, this cheap, simple job is just a part of routine maintenance on any motorcycle. If your spark plugs are loose or burned out, they need to be replaced. Just like anything, they wear out over time. Your spark plugs are the ignition spark that start’s the whole process. Like most motorcycle motors, the DT 125’s motor runs on combustion. In most cases, the stalling was a result of worn spark plugs or a bad ignition coil.

Some owners of the DT 125 found that their engines often acted erratically while they were riding.

When you start your bike, you expect it to keep running. The most prominent of these problems is engine-stalling or “cutting out.” If your engine is stalling, your day of trail ripping becomes a day of wrenching pretty quickly. We’ve encountered a few Yamaha DT 125 owners who have complained about engine issues, who’ve shared their troubleshooting. The engine is the heart and soul of a motorcycle, and nothing inhibits a bike’s performance quicker than engine issues. What’s The Resale Value On the Yamaha DT125?.General Pros and Cons of the Yamaha DT125.– Bike Won’t Rev Past a Specific Limit:.

Pieces yamaha 125 dtlc 1989