Just gave the Capo motor a service. No drama, everything went according to plan. I just thought I’d share a couple of pics of the inside of the airbox – with the modified breather – straight after the air-filter assembly was lifted. No cleaning, no Photoshop ….. just as it looks after 5,354 miles. The throttle butterflies, velocity stacks and idle air control valve (IACV) are all perfectly clean.
The extended drain tube from the airbox (down below the oil filter casing) held about a spoon full of oil when drained and what can be seen in the photo was only a light coating in the bottom of the airbox. One sheet of kitchen towel had that as clean as a whistle in a few seconds. Since doing this breather modification I’ve ALWAYS run the oil level to the HIGH mark on the tank. So without the tedious job of removing and cleaning out the complete airbox, it was a pleasure to simply replace the Athena air filter and button everything back together.
You may (or may not!) have read the post a couple of months ago – Fixing a few Capo niggles. That was where between Continental trips, the original air-box molded connection for the crank-case vent was drilled out and a new 90° bulkhead coupling and pipe fitted to drain any oil into the front of the airbox, well away from the throttle body and IACV (Idle Air Control Valve).
Now with the Caponord seriously (+1,000 miles) overdue a service, I got stuck in and removed the tank ready for plugs/air filter. I admit to being really pleased to see no oil what so ever in the upper part of the airbox and only a tell-tale smear in the front section. A syringe sucked what oil there was from the drain tube – approx. 5cc @ 3,000 miles WITH the oil tank filled to the HIGH mark.
Previously it didn’t seem to matter where the oil tank level was, oil kept getting thrown into the airbox and sucked down into the throttle body. Look closely at the design of the airbox and you see the ‘fenced’ in area (red) around the velocity stacks – and of course, the two slots in the stacks (arrows) for excess oil to drain through.
It’s pretty obvious then that Aprilia/Rotax EXPECTED regurgitated oil – and tried to ensure it was fed back to the engine and burnt. Unfortunately that isn’t always the case and when some bikes are left on the side-stand oil manages to get over the ‘fence’ and muck up places it shouldn’t!
Of course a little hot oil can spread a long way and look far worse than it really is ….. I guess it just niggled the hell out of me each time I lifted the airbox lid. In hindsight it’s one of those quick jobs I wish I’d done years ago.