Just got an '02 426F. After riding 2-3 hours, it comes up short on the dipstick (uses approx. 1/4 quart of oil). Plug looks good so I don't think it 's burning it. It's messy around the puke tube. Will they puke out this much oil during riding?
These engines need ring and piston replacement sooner than you may think. The pistons have a very short skirt and wear very quickly. When they wear, they start to rock in the cylinder and wear the sharp edges of the rings down. If I were you, I would check the top end for wear. The recommended oil viscosity for your engine is 10W-30. 20W-50 is a bit heavy unless you are riding in very hot conditions.
Also, check the valve guides for wear and replace the valve guide seals.
If you wait too long to disassemble your engine, it will disassemble itself. :yikes:
A leakdown tester would be handy to have. Might be worth it to have your shop perform a leakdown test. The leakdown test will help determined if you have valves that are not sealing or if you have worn rings. Worn rings will allow compression to blow by the rings and into the crank case and it will be come pressurized. The end result is a pressurized crank case will purge oil out of the breather hose.