Pressure Check a 2-Stroke Engine

Reader Contribution by The Motorcycle Classics Staff
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Owners familiar with 4-stroke motorcycle engines often find themselves at a loss diagnosing poorly running 2-stroke engines. A 2-stroke engine is simpler (no camshaft, valves or valve gear), so by extension that should make it easier to work out issues with poor performance. The frustration comes when you can’t get your oil burner to run right even after confirming adequate compression, proper carburetion and correct ignition timing.

Recently, we hit a wall trying to get a 1973 Yamaha RD350 2-stroke running properly, so we turned to Brad Obidowski of HVCcycle in Lincoln, Nebraska, for help. A 2-stroke fan and RD350/400 fanatic in particular, Brad has acquired a great deal of knowledge about Japanese 2-strokes. After we described our RD’s running problems to him, Brad offered to spend a few hours showing us the steps he goes through diagnosing 2-stroke performance issues.

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