I wonder if anyone can confirm any differences in the various iterations of inner Clutch covers. I've sort of convinced myself it will be OK to use an earlier cover on a later bike, but would appreciate any knowledge anyone has. The reason for asking is I want to use this cut-away cover from a 90's 900SS on my 1000SS/SL Mongrel: Without taking the cover off the 1000SS I can't see any differences externally, and comparing parts diagrams there only appears to be the one obvious difference which is this blanking plug: Which is missing on the older cover: From researching it, the blanking plug was introduced in @2003. The older cover has a cast in oilway to divert an amount of oil up to the end of the Crankshaft: And I'm assuming the newer one does too. The inclusion of the blanking plug looks to me like it was added so the Oilway could be drilled out from the outside of the cover after casting rather than trust that it was cast in properly without being able to machine it. Perhaps they had a large fall out of castings without a good enough quality Oilway? Or, perhaps I'm taking too much of a risk and the machined Oilway is bigger etc. Does anyone know for sure before I go to the bother of draining the Oil and stripping it down? Thanks.
The size of the oil way at that point only matters if it is smaller. The amount of oil going through is determined by the the area that's most restricted which is more likely to be at the crankshaft. If it was me and the hole I marked in the picture is the same or bigger I'd fit it and not worry about it. I would agree that the plug was added for easier casting, machining and cleaning.
As above, the oilway size is likely to be different. I fitted a 1000DS oil pump to my M900 for increased oil flow and the outlet port on the DS pump is much larger than that of the M900, so much that it wouldn't mate with the hole in the side cover as pictured above (the 'O' ring would just fall into the pump) so the oil would just leak back into the engine rather than circulate the oilways. I had a 'tophat' bush made to fit into the oil pump, reducing the bore to match up with the older casing - looks like you would have the same issue.
Thanks Petsmith and Dukedesmo Yep it's all about the smallest restriction in the Oilway. I've had some time on my hands stuck indoors at home this morning so have managed to do some research online and I think I've concluded it's not worth the risk. Finding a newer style cover for sale on Ebay has provided an image of the inside to compare which shows a much larger diameter entrance to the Oilway exactly where Petsmith circled and as Dukedesmo's info. I also popped out to the garage pulled the plug from the one on the bike and it appears that a bigger size hole goes all the way up the cast in tube than the older one: Obviously I can't see the exit point of the Oilway at the Crankshaft end, but it would make sense that it's larger as well. The benefits of the 900 cover I have are that I brought it really cheap a few years ago, it's already machined, and the Gold Paint is in great condition. But it looks like I'll be selling it on now, buying a later one, and converting it. I can machine it myself, and do the painting, but if I buy a rough one will probably have to concede to getting it media blasted by somebody before I start. ,
IIRC, the reason for the larger flow oil pump on the DS motors is because it uses plain bearings for the camshafts rather than conventional bearings in Monster/SS heads and so a better oil flow was required. Don't know whether the crankshaft oiling is any different though? I used the DS pump because, even with a restricted outlet to fit the Monster case, it flows more oil which can never be a bad thing and I fitted direct oil lines from pump to camshaft oilways, blocking off the oil flow from cylinder to head which never seemed a particularly sophisticated setup IMO, using oil that (eventually) rises up through the head (whilst picking up heat) to oil the cams & rockers - now the oil through the cylinder jackets is just for cooling.
When I fitted an early 888 Corse mag' cover to a later motor, with it's pressure relief valve integral to the pump, I had to remove some material from around the inside of the oil level window to give clearance.
Looking into this has turned me into a complete inner clutch housing Anorak. Just for completeness I've noticed that there is another later version of this cover with yet another cast in boss which is on my 999 but also appears to be on the parts diagrams for the 998 and 1098. Images taken from various Ebay adds. As well as the boss and drilling for the Oilway that appears on the outside by the Sight Glass, there is another up by the Oil filler hole: Which does not appear to be blanked on the outside with a plug, but there is something going on inside with a Grub Screw: These images from parts lists could be easier to follow: Don't really want to take my 999 to bits to investigate further. .
Looking at images from when I was rebuilding my 999 I can see now that there is in fact an Oil line connected to that point which is not the case on the 1000SS DS motor:
Does the drilled oilway changeover also coincide with the crank seal flipping around? Brad the bike boy talks about the seals in one of his videos and how their orientation changed when oil pressures were increased I think.
