Can anyone enlighten me as to what differences between the motors is? A friend is considering building a 748/1098 and has been offered a SF motor. Any reason not to go for the SF motor rather than a Superbike one??
as far as i know the sf motor is slightly lighter than the 1098 as it uses 1198 cases with the sfs coming with mag clutch and valve covers as well as carbon belt covers making it about 3 kg lighter than the 1098. It also shares the 1198 gear box maybe? I know its down on hp but think that is mostly due to the sf air box set up? tho im sure i shall be corrected soon!
Don't quote me 100% on this, but same as Chizel said. 1098 Streetfighter engine uses the 1198 engine cases. From what I read, that alone saved some weight. Had a quick scan on the net earlier as I was trying to figure out what engine i've just bought is for the same project as your mate.
My SF engine was recently stripped for blue-printing and balancing. I was advised beforehand that the 1098 main bearings were suspect and would be better replaced with an earlier type of bearing which are much stronger. (This was going by the engineer's 1098 SB experience and one of the reasons for having the work done). When they got the engine apart they found the SF already had the older bearings which they weren't expecting. Could this be another difference between the two which is down to the different crank cases? I don't know but it would be worth looking into. If SF engines do have better mains and lighter cases, that would clinch it for me. I do know the gearbox and the heads are the same and the 5 bhp difference between the two bikes is due to the SF having a smaller airbox and shorter ducts necessitated by the naked format, so use the SB box and plumbing.
[Q All good stuff! have the 1098 sfs waiting in the workshop.. like the bearing thing if thats a fact...cant use the sf or 1098 air box if goin into a 748/916 type frame so thats a moot point.. nelson has done a few transplants.. nelson.. NELSON!!!! get the fuck over here
This is a quote from a test Ducati Streetfighter S | Ash On Bikes "The exhaust system is new with fatter pipes than the 1098, at a chunky 2.3-2.5 inches (58-63mm) diameter. The engine itself is essentially a 1098 motor but with 1198 crankcases, used because these are made with the new Vacural process that reduces weight – some 6.6lb (3kg) is saved this way. Indeed Ducati’s obsession with weight minimalisation has resulted in an overall dry weight of just 373lb (169kg) for the stock model and 368lb (167kg) for the S."
so given what we know so far as in the air box has to be changed anyway, the sf engine is lighter and perhaps has the better bearings than the 1098 , unless there is something negative to add the sf engine would be a better transplant!
Reading Estranged's quote had me reaching for the calculator. My SF now has 162 bhp at the back wheel. If my maths is right, with a dry weight of 167 kg that equates to 969 bhp/tonne. That's the ticket. :Woot:
