I thought I would put in my $.02 dirtsurfer since it is different from most everybody's.
I think it is funny how so many on the net are all for after market big bore kits in order to get another 70 or 90cc's over a "1000's" 980cc's and the resulting cylinder walls and gasket sealing surfaces that are too thin but then advise against BMW's own "big bore" kit which is what a 1000cc BMW really is if you think about it. The main differences is that the BMW setup gets you 200cc's instead of 70 or 90 and it leaves the cylinder walls and gasket sealing surfaces with just enough to work correctly. There are lots of good reasons why BMW stopped hogging her out at 1000cc's!
800's are a bit smoother but I don't notice it that much. I guess it is because, judging by inmates mileage reports, I ride at higher speeds and RPM's. I don't get NEAR the reported mileage on the net and neither do a bunch of my friends and customers from what I have heard growing up and working in a BMW dealership and then working at three more of them so far plus having my own shop. Vibration wise, 1000cc's never bothered me.
Power wise? I think there is a substantial difference in the additional 200cc's. I have converted many a R80GS and the back to back difference is HUGE. It's hard to keep the front wheel on the ground in first! Yes, if I converted I would re-gear and get a different speedo as well but all the extra power is what gives you that option! Personally, I can't see running smaller than 1000cc's when the external dimensions of the engine remain the same. The weight barely changes as well. I wonder if a 1000cc weighs less than a 800? Either way, it's a win/win as far as I am concerned. You get a bigger bore that still isn't TOO big.
supershaft screwed with this post 02-18-2011 at 11:10 AM