Hi, have just rebuilt the top end on my 1999(i think) wr400f as was blowing oil out of the breater pipe. Put in new rings, valve seals, gaskets ect. The engine smokes quite a bit, not always though, and using quite alot of oil. was out all day and used approx a litre. runs fine but just smokes. Did an oil/filter change today , put in 1.6l into warm engine then ran for 1min to check level, nothing showing on dipstick, bike smoked horrendously but did clear a bit. took bike on 5 miles run, smoked a bit, engine oil level was half way up dipstick. Not sure how the oil system works, know there is reservoir i n frame, am i right in thinking oil pump may not be pumping oil back up into frame as pump not working properly, or is there a valve gone wrong or blockage? maybe oil is sitting in what i believe to be a dry sump makeing it smoke bad as it does? Did pump some up after a 5 mile run after i say with less smoke, maybe pump is weak? just guessing here what may be wrong, any help appreciated thanks!