peterb

Hello Alex, with the later design crankcase that you have (2015) the oil ways are not drilled. The LHS crankshaft has two oil seals to prevent drawing in air. There should be no oil in this area. If the LHS seals had failed then you would be drawing in excess air into the crankcase. What colour is the smoke? Blue is gearbox or excess oil in the fuel oil, white would be coolant. Early 2015 Ossa's were supplied with an incorrectly specified RHS oil seal that did not last long, this would allow gearbox oil to enter the crankcase. A bit more info on the symptoms would help ID the problem. Bye, Peter.

Thanks for your response peter. It smells a bit like crank oil but it is hard for me to tell as it may be an accumulation in the pipe from the previous owner? It appears to be intermittent...it will run ok and then smoke a lot. I was told to check the throttle position but I don't have the cable, just the software.

The Ossa's were all supplied to us here in NZ running too rich, so we always had to lean off the mixture. You can use a hotter plug, a number 4 heat range always worked well for trials riding. Intermittent is a bit odd, but may well be the mixture too rich. You need to find someone with a cable and software set for your later model ECU, where abouts are you?