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I been working on a 1990 DT100 for a while now. Here is a quick summary:
I got this engine with the heads taken off for a head gasket change. The previous owner had broken several bolts and gave up on it. He told me it didnt run properly.
After getting the heads back on, it started right up, but did not run correctly. No way it would idle.The plugs were fouled, some were dry and some wet, and one of the cylinders were obviously colder than the other after running for a little while
The first thing i did was to take the carbs off, cleaned and put new gaskets/jets in. Also set the pilot screw to factory settings. I noticed two of the reeds were bent, so i changed them out.
Again, it started right up, but still performed poorly. Maybe some change but overall the same symptoms.
Checked compression, approx the same on all cyls, from 105-110 psi
I then got a complete new CDI box with electronics from another engine. Because it was from a never model, i had to change the flywheel/stator too. After this i checked all the resistance and voltage measurements, and it matches the service manual.
Again, it performs as before, maybe some variations, but a combination of black/wet/dry plugs.
After all these fixes, the only thing that has been with me the entire time is the oil injection system, so yesterday i filled a small tank with 1:50 mix, and removed the oil tank from the engine.
It still did not idle, but that could be carb tuning.. however, after running it for a minute or so, all the cylinders seems equally hot and the plugs looks way better (all my plugs are now a bit messy so hard to say 100%)
1. Could the oil injection system give these symptoms? I have never heard of a system failing so that it feeds too much oil?
2. I am using a random branch two stroke oil, and have done that since i got the engine. Is that an issue?
Any input is much appreciated!
I got this engine with the heads taken off for a head gasket change. The previous owner had broken several bolts and gave up on it. He told me it didnt run properly.
After getting the heads back on, it started right up, but did not run correctly. No way it would idle.The plugs were fouled, some were dry and some wet, and one of the cylinders were obviously colder than the other after running for a little while
The first thing i did was to take the carbs off, cleaned and put new gaskets/jets in. Also set the pilot screw to factory settings. I noticed two of the reeds were bent, so i changed them out.
Again, it started right up, but still performed poorly. Maybe some change but overall the same symptoms.
Checked compression, approx the same on all cyls, from 105-110 psi
I then got a complete new CDI box with electronics from another engine. Because it was from a never model, i had to change the flywheel/stator too. After this i checked all the resistance and voltage measurements, and it matches the service manual.
Again, it performs as before, maybe some variations, but a combination of black/wet/dry plugs.
After all these fixes, the only thing that has been with me the entire time is the oil injection system, so yesterday i filled a small tank with 1:50 mix, and removed the oil tank from the engine.
It still did not idle, but that could be carb tuning.. however, after running it for a minute or so, all the cylinders seems equally hot and the plugs looks way better (all my plugs are now a bit messy so hard to say 100%)
1. Could the oil injection system give these symptoms? I have never heard of a system failing so that it feeds too much oil?
2. I am using a random branch two stroke oil, and have done that since i got the engine. Is that an issue?
Any input is much appreciated!
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