Tuning
Engine tuning is expensive and can make the bike unreliable. Mez Porting are the acknowledged experts for gas flowing. Valve guide wear can be high when larger valves are fitted due to standard guides being short. Longer guides have been made and installed. Standard valve seats will accept a small increase in over-size valves external oil supplies to camshaft bearing blocks fitted to cure persistent leakage from internal supply O ring. Extensive modifications to engine can be done. Large valves (inlet from 750
Monjuic) and gas flowing produce good results without impairing reliability. CC capacities above 498cc available are 583, 598, 612, 640, 650*, 680, 750*, 850*, 920* (* = longer stoke crank used). 650 engine from 650 SL and Alazzura regarded as desirable. Crankshaft on one F2 racing bike has been modified by cutting flywheel and alternator rotor part off, and rebalancing. Removal of flywheel enables engine to build up revs quickly. Alternative ignition system required. Engine tickover of 6000 rpm on the F2 bike. Oil cooler can be plumbed in by routing line from oil pressure switch tapping in crankcase (10mm x 1.0mm) through cooler and into camshaft bearing blocks. Restricted line can be extended from cam feeds to supply oil directly to gear selector drum via tapping on rear of crankcases. Internal oil feeds to heads blanked off by dowel in feed drilling of barrel or head. This method cools oil to heads only. Complete engine cooling is done by having clutch cover modified to accept tappings coinciding with oil pump outlet drilling and crankshaft inlet housing in cover. Internal oil passage in cover is ground out and blanked off by welding. A restricted by pass line can be installed between the supply and return lines to give instant oil supply to crank on start up. Later 750 type crankcases have double tappings to accept cooler as standard, MOCATI engine oil temperature conversion fitted to one bike using sender unit tapped into oil strainer plug.