How does the exhaust valve function and what can cause it to leak?

May 10, 2023 ... Yes - had it (and not running due spark plug) a number of times on motorcycles. Sometimes the original will work fine once started with a ... Jun 23, 2009 ... Carbon fouling is caused by weak spark, wrong plug heat range, and rich conditions. Essentially, you're burning too cool. Need to heat things up a bit. Jan 31, 2020 ... Gentlemen, I have a sooty, carbon-fouled spark plug problem that I ... carbon building up on the exhaust valves causing them to leak. Jul 8, 2010 ... Carbon fouling - Dry, black sooty deposits leading to misfire and weak spark. Caused by an over-rich fuel/air mixture, faulty choke operation or blocked air ... Sep 1, 2020 ... ... caused the engine to run really rich, which ultimately caused the carbon-fouled spark plugs. Does this sound at all plausible? I don't know ... Dec 31, 2020 ... Spark plugs fouled with black residue, often greasy in quality. After cleaning off plugs, she starts/runs well, for a few more weeks, then ... Sep 26, 2022 ... Carbon Fouled Spark Plug – Find Causes & Solutions · A dirty air filter · Faulty fuel injector · Too rich air mixture · Failed oxygen sensor. Apr 12, 2013 ... ... cause the plug tip temperatures to decrease and carbon deposits to accumulate, possibly causing fouling and misfires). A solution to this ... May 31, 2018 ... If the spark plugs have a matte black or grey appearance, it could be carbon fouling — something typically caused by a fuel mixture that is too ... Nov 11, 2017 ... ... spark plug gets a lot of carbon build-up. Any ideas please because i'm running all sorts of tests and cannot find the cause. Thanks in ...