And just to add that the preventative maintenance is extremely quick and easy to perform, if you don't want to re-route the Factory vent tubing. I simply pulled off the bottom hose at the engine and pushed it into an empty 2-litre water bottle (a small amount of oil came out of the engine as it had not been started for a while and some was clearly in the sump), then pull off the tank end and use a blow-up lilo adapter on a pushbike tyre pump to blow the clag out and into the empty bottle. Mine cleared after the first couple of pumps, but it did take a bit of pressure to do it. Nasty clag fired into the bottle with quite some spirit, but now it's nice and clear. I've not done this before and I doubt these were cleared out when the chassis was changed last summer at the Factory, so i presume this build-up has taken a while to accumulate. I will repeat this simple 10 minute exercise each year I suspect.
The bottom line on the engine drain the tank.
And if you are just blowing air up a hose that is connected to the tank you will be blowing crap up into the clean oil. I would disconnect the line at both ends and then clean it.
