SF crankcase front right stud oil drain hole

piranha-bro2

piranha-bro2

Hero member
Location
Melbourne
In the process of fitting a new inner web to a late SF1 motor (mid 15,000s) that's ratted out the RH spline and noticed that the drain hole that runs from the front right stud to the gap between the starter freewheel seal and the RH main bearing (gravity oil feed to RH main and starter needle roller) ... is missing. I can only guess that siesta time got in the way just as Lorenzo was about to finish off his case (of vino??) and he forgot to drill it.

I've got two other SF cases here (one early SF1 the other early SF2) and they have them ... as does every other SF I've ever worked, so must assume it's an oversight at the factory. Out of interest has anyone ever seen one like this? I'm in the process of drilling it, but it ain't easy, as barrel and case studs get in the way everywhere and it's a very awkward and tight angle to get right by eye.

Doesn't seem to have had any ill effects on oil supply, but drilling it regardless - and no, the spline didn't rat out due to lack of oil ... that was the after effects of a major seizure that left the rod in the shape of a horseshoe!
Quentino
 
Never seen one undrilled! - I'll make sure I have a good look at all of mine - have got a few around that number!! - Regards - Phil. - P.S. - Could be time to do that "Big Pin" conversion  :D :D
 
It is not something to risk getting wrong. Could it be done on a milling machine to get properly lined up?
Isn't it for getting oil to the starter clutch needle roller? If the bike has high mileage and the starter clutch has been ok it could be a case of unnecessary overkill on the factory's part.
 
Not on the rollers and plungers Paul, but the inside needle roller gets engine oil, hence the oil seal. Would have been better with the lot in oil imho.
 
Tippie said:
Not on the rollers and plungers Paul, but the inside needle roller gets engine oil, hence the oil seal. Would have been better with the lot in oil imho.
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You are of course right.

:-X

Paul

 
Tippie said:
It is not something to risk getting wrong. Could it be done on a milling machine to get properly lined up?
Isn't it for getting oil to the starter clutch needle roller? If the bike has high mileage and the starter clutch has been ok it could be a case of unnecessary overkill on the factory's part.
Click to expand...
I had a crack at bolting it to the bed of the drill press, but it's impossible (at least without removing all the crankcase studs). I've done half from the top side and need a long shank 5mm drill to go in from the bottom - where the tunnels will meet beautifully in the middle, just like Norwegian road tunnels bored into mountains all over their lands  ;)
Judging by the way it all looks, I agree it's probably overkill -
but the factory may also have had the RH main in mind, as it's blanked off compared to the drive side and above the baffle - so effectively the only bearing not receiving some clear oil feed or splash.

Got other plans for the big pin convert, Phil  :o but this motor goes back to the owner without any more of my time than I have to donate to it  >:D  Then I start on my SFC crank - new balance factor, rods, mains ... hopefully a smoother 270 than it was when I last rode it.

Thanks to replyees.

Quentino
 
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