Question-------------------------
Thank you for the reply. Wiseco has a 3-13/16" flat top piston and cylinder settup that fits sportsters with stock 1200 heads. They also have a same size settup that fits thunderstorm heads. If I use one of these settups, which head would be best for keeping the torque in the low to midrange rpms? What is the differences between stock 1200 heads and thunderstorm heads? Do the t-storm heads have smaller chambers and larger valves?
Thank you
P.O'Toole
Followup To
Question -
The bike: 1997 sportster 883 converted to 1200cc in 1999. It has dished S&S pistons and the original 883 heads with little head work performed.
Is it possible to bore the crankcase cylinder holes large enough to install cylinders with 3.75 inch inside diameters? Wiseco says the holes should equal 4.005 inch.
Presently, the cylinder holes are approx 3.625 inch
Thank you
Answer -
Yes you can. the problem you will run into is that the motor will have to completly torn down and the cases split.
Good luck with your project and happy riding
Mike
AnswerGoing with the thumderstorm will give you the best setup. Bigger valves, which will help the bike breath better, and a higher compression, which will help with torgue.
I would suggest changing the cams to go with the heads. The stock cams wont have enough lift and duration for the potential of the heads you are planning on using.
Good luck and happy riding
Mike
