Jakob 1 Posted October 18, 2008 (edited) Some theory: Having the inlet valve area from a XU10 top and a 1.8 crank in a XU block should/may give almost same tourge as with standard 86mm crank, as in theory it will peak further up the rpm line and thereby giving more hp. Therefore adding a XU7JP4 crank in a XU10 block could be interesting in some situations... (XU block would be with oil spray bars under pistons e.g. XU10J4R, J2TE, RS etc). Pistons and rods figures (XU7JP vs. XU10xx) XU7JP: (BFZ, LFW, L6A, LFY, LFZ, L6B) - Length: 150.5mm - 48,655 mm - 22 mm XU10J2: (RFU, RGX, R6D) - Length: 152 mm - 53,695 - 22 XU10J4 (RFT, RFY) - Length: 152 mm - 53,695 - 23,003 XU10J4RS: (RFV, R6E, RFS) - Length: 158.00 mm - 53,695 - 22 The rod bearing diameter is different from XU10 versions, but using the XU7JP rod should fit a XU10J2 piston (22mm) Questions: 1) Have anyone fitted a XU7JP4 crank in a XU10 block? 2) Would the crank fit? 3) What are the crank diameter (81mm?) 4) Anyone got pictures of the crank and rods? - the crank should be full counterweighted I am looking for a CR 9:1 with a XU10J2 head and havent done the math yet (missing crank diameter and dish from XU10J2 head and pistons) Maybe some standard components could be used (any experience?) else custom pistons/rods. /Jakob Edited October 18, 2008 by Jakob Share this post Link to post Share on other sites
Sandy 191 Posted October 19, 2008 XU7 is 81.4mm stroke. It's do-able, but you'll need custom rods. The XU7 big end is 45mm Share this post Link to post Share on other sites
Jakob 1 Posted October 19, 2008 XU7 is 81.4mm stroke. It's do-able, but you'll need custom rods. The XU7 big end is 45mm Thanks. What do you mean by 45mm big end? I have found 22mm and 48,655 Share this post Link to post Share on other sites
Sandy 191 Posted October 20, 2008 48.655 is the bore in the rod, with the bearing fitted it's 45mm. Share this post Link to post Share on other sites
Jakob 1 Posted October 22, 2008 48.655 is the bore in the rod, with the bearing fitted it's 45mm. Thanks! - anyone else with experience on this swap??? Share this post Link to post Share on other sites
Jakob 1 Posted November 4, 2008 Anyone with experience?? Would the crank fit straight in?? Share this post Link to post Share on other sites
guffe 2 Posted November 5, 2008 Anyone with experience?? Would the crank fit straight in?? It should. XU10 crank didn't fit straight into alloy block (would have needed some grinding) but vice versa should fit just fine. I can't be sure because I just sold my XU7 crank. Share this post Link to post Share on other sites
