Anyone here know anyone or done it themselves - converted an 1150cc to 1200cc using the 1200C barrels and pistons etc ? Can it be done the same way as the old airheads could be converted from 800cc to a 1000cc , or is there a catch somehere ??
It would cost more to do this conversion than to buy a new 1200 bike. The internals of the 800 to 1000 cc airheads were pretty much the same, the 12000 engine isn't quite identical to the 1150.
You could punch it out a little, but then integrity is in question. Ride the mutha-fooker and be happy. My 1150 rawks! Wanna race?
Does the 1200 make much more torque? I thought its main advantage was reduced weight. Some engines were made to be hot-rodded, but I don't think the BMW boxer is one of them.
I think Neil is talking about fitting the barrels from a 1200 Cruiser - not from an R1200GS... Mike :)
The extra displacement on the 1200 comes from a longer stroke. In other words you need to replace the crankshaft. The bore is the same.
You're probably right. I don't remember anyone praising the performance of the Cruiser in comparison to the GS.
Worse engines than the boxer have been hot-rodded and the boxer engines have been hot-rodded for years, and as you've noted, with bigger bore jobs than the one being discussed here. A 50 c.c. big bore is attainable at a reasonable expense. The real question is, why stop @ 1200 c.c.? The Husaberg F650e single cylinder has a big bore kit that takes it to 750 c.c. so a 50 c.c. increase on a tiwn is reasonable and the integrity of the engine should be able to be maintained. I'd start with pricing out a set of pistons from an accreditted piston manufacturer such as Wiseco to determine whether you want to continue this endeavour. A matched set of Wiseco pistons are pricey enough, a custom set might be significantly more. Then add in the full exhaust system and power commander that are required to get full benefit from the engine gains you've considered. I'm interested in you research results, keep us posted, thx.
Don't you people read? It isn't done with bore, it's done with stroke. It would be easier to swap in a whole cruiser shortblock than to swap cranks. Look up the part numbers for the cylinders on a 1200c and an R1150R with the black cylinders, same number.
Ironically... Couple of weeks ago I talked to a 1200C owner who said that he and some of his crowd have put GS cams into their C heads for a way to make a smidge more power. Back to the GS. I think that the 1100S or 1150RT parts lists might make more sense than anything with a "1200" in the model name.
Thats what i needed to know - Thanks . Had a chance to buy a wrecked 1200 C ( cruiser), never had one apart pr worked on one before, so i thought i'd just ask a quicky question asking if anyone had done, or knows of anyone who'd done it - think i'll give this idea a miss .
