There is a check valve in the clutch cover whose purpose is to not allow the oil to drain back into the crankcase when the engine is not running.AndyL wrote: Thu Jan 22, 2026 12:20 pm Sorry to ask such a dumb question...just need a bit of clarification for my new to me 3AJ. I've just put a new clutch in the bike and the engine and oil tank are both completely drained. So I need to refill and start it.
I've put a litre of fresh oil in the tank...expecting it to drain into the engine - but the level hasn't dropped!
How am I meant to fill and prime the engine ready to start it.....Thanks in advance.
Andy
1)Fill the tank with oil, then disconnect the oil pipe that connects to the crankcase (gear lever side) and let oil flow until you see no air bubbles. 2)Connect and retighten.
3)Fill the oil tank with oil again if necessary, crack the air bleeder screw on the oil filter loose and start engine. Once no air bubbles are visible, tighten it.
4)Let the engine warm up for a few minutes. Now keep the bike in upright position and in idle for at least 10 seconds, then shut it down.
5) While keeping bike upright, check oil level without screwing in the dipstick.