I'm checking the valve clearances on my 2006 749 @12,000 miles, i have done a bit of online research and there is mention of running the clearances tighter than the Ducati service manual spec of 0.13 - 0.18 openers and 0.18 - 0.23 closers. Just wondered if anyone had any experience of running tighter clearances, i would prefer to get the best running condition of the engine and dont mind checking the valves more frequently. Any opinion would be appreciated and what clearances are recommended?
I have had my 749 from new since 2003 and had Baines Racing service the top end. I believe they shim to tighter tolerances and it means that the engine runs smoother and you have a little more lee way as far as service interval is concerned. Too tight is as bad as too loose, though you can always tell when the shimming is out as the engine feels "wooly" and sometimes spits back through the airbox. Speak to Geoff Baines , Nelly (on here) and any of the well respected engine guys and they'll be able to advise. Neil Spalding (Sigma Performance) recommends shimming to factory manufacturers spec rather than service spec see here: What is a Full Monty - Sigma Performance Ducati "Ducati's age differently to other bikes too, with the Desmodromic valve system there are no heavy valve springs banging the valves shut against their seats, instead the various rockers and levers get the valve very close to its seat and then the rising gas pressure as the piston comes up under the valve finishes the job of closing the valve. This means that the bike works a whole bunch better with clean gas tight valve seats and it also works nicer if the clearances are accurate…the snags normally are that without a big spring closing the valve its is a lot easier for the seat to become dirty and leak.. Also to try and reduce the costs of Ducati ownership the factory have expanded the range of acceptable valve clearances, now its not that these wider 'acceptable' clearances cause damage, its just that the bike runs a lot better, smoother and more powerfully if the clearances are reset precisely to the original numbers at each service."
