View Full Version : Question about bigger displacement possibilities

5th February 2005, 02:06
I have a 70' XLCH, which is a 900cc. I was wondering if the 1000cc cylinders and pistons would fit in my stock cases? If so would I also have to change the heads and rocker boxes? I have to buy new parts anyway and the 1000cc stuff seems to be a lot more prevalent and cheaper than the 900cc stuff. Im just looking for some feed back on wether or not its worth the trouble before I buy the parts.

5th February 2005, 02:42
The answer to your question is in the December 2004 issue of American Iron magazine, the article Sportster Corner, page 138. Here is some of the info for 1970:

no hi-compr 900 pistons are available but if you increase the crankcases' cylinder spigot bores a 1000cc top end can be installed once you modify the base bolt pattern. You can then buy hi-compr street pistons from K Black and others. S&S has 3-3/16"-bore med-compr street pistons. Or you can keep your 900 cly & heads and buy over bore pistons from F&S.

Good article. But he omits 1979 - 1981.