The "tuned for racing" donor engine that I'm using parts of for my 650SS restoration has not been treated with the TLC that it deserves. I had hoped to use the oil pump but it would appear to have been modified. The fixing holes have been opened out to 3/8", and the crankcase modified to accept 3/8" cap screws to hold it in place. Also, a couple of the teeth on the six start crankshaft worm gear are chipped at the "nut" end. It seems I have a few options... Modify the matching numbers crankcase to suit... I don't think so!. Make up a couple of sleeves to reduce the oil pump holes back to 5/16"... possible. Replace the whole kit and caboodle... probably best.
So... I've heard stories of engines 'over oiling' with the six start gears fitted. Is this really a problem? Would I be best advised to replace the pump and fit drive gears with a three start set?
Any advice really appreciated.
Thanks, John
There is a banjo bolt in the…
There is a banjo bolt in the timing cover that feeds oil up to the rockers. Not sure about the camshaft end.
Yes... I had thought about sourcing another pump. There seem to be quite a few available. It's whether I go for a 3 or 6 start gear set.
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Your description suggests pressure fed rockers. In which case you will need a 6 start oil pump. A 3 start set-up will only deliver around 12 to 13 gallons of oil per hour at high revs. The 1.75" big end journals of the 650 engine plus a pressure rocker feed need at least 16 gph. A 6 start oil pump will easily deliver that and dump any spare oil inside the timing cover.
Note.......you can use an early Commando oil pump and drive gear set on your engine.
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Thank you Phillip Hannam... That was the information I was looking for.
John
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John....does your engine have a pressure oil feed to the rockers and possibly to the camshaft end (Race mod)? Your oil pump does not look too healthy on the outside. Have you checked the condition of the inside components? Oil pumps are available new or in good condition second-hand.