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2015 Suzuki DF 250 TX with 150 hours. No codes, no issues, motor runs fine, with one possible exception. I thought I noticed a drop in rpm (200 or so) while running in a head sea at the end of last season. Now, I know there could be a number of reasons for this, but when I pulled the plugs to check them at the end of my season, I discovered that I didn't torque the plugs properly at the beginning of the season - they were just hand tight and came out very easily. I now only use a torque wrench and torque to specs. The plugs looked good, except for the bottom two cylinders - found rust on the base ring only of the plug on the bottom right side (see image), and very light on the bottom of the left side. Based on this, I scoped the cylinders and did compression test - neither revealed any issues. Cold compression showed 1)140 2)150 3)140 4)140 5)135 6)135. As the motor was cold, I believe this is acceptable. Questions: I assume loose plugs lead to loss in compression and corresponding occasional loss in rpm - comments? Based on the image of the plug, is that actually rust, or evidence of a hot plug? Could the rust simply have been result of condensation collecting at the base since the plug was not properly mated to the cylinder head? Any other issues I should be concerned with?
Appreciate it!
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Appreciate it!
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