Going to be building a 80ci+ engine not sure if i will go with a 80, 88, 90, or 100ci yet. has anyone built one. if so let me know how it went or is going. did you go with s&s, axtell, Nrhs, zippers or something else. what didi you do to complete it and was it worth it. thanks

 

I did build an engine bigger than 80". Of course, it was a Dodge Hemi, but it was bigger than 80"!

Sorry, had to get that wise-*** out of my system. I haven't been personally involved in a large-inch Sportster motor build in quite a while. However, I know Dan at NRHS to be a real stand-up guy, and a master of customer service. I just recently saw an instance where the customer fried his motor through incompetence during the build, then again through abuse right after the build (no break-in, full throttle). Dan's answer? "Send me the motor, I'll build it right, and only charge you for the new parts (emphasis added)! This wasn't an issue with Dan's parts quality, it wasn't an issue with build instructions, it wasn't an NRHS problem at all, but he fixed it anyway.

Size? 88" or 90" for me. Why? (The following is my understanding from anecdotal evidence as I have only been involved in one large inch Sporty - 88", a while ago - and not from personal experience) The 80" is too small (only 6" bigger than stock, and not much more HP or torque), and the 100" is too slow. This is a very rough and low-revving motor, and is not happy much above 4,000 rpm.

If you're going to do anything more than a very mild build, I'd get S&S cases and Carillo rods.

 

Did a S&S 88 Sidewinder for my Evo Big Twin a few years back. Not sure of what your asking though but you can go to the S&S site and get all of the info. Wasn't very complicated but I have done a few Big Twins in the past. A little steeper curve than bolting on new handlebars of course but if you have done any kind of engine rebuilding in the past then it shouldn't be too hard for you. Give it a shot or ask a friend for help before you take it to a shop because there is no better way of getting to know your bike.

 

Here's what I have for a Winter project

NRHS 90" kit with -9.5 cc reverse dome pistons, .040 head gasket and my Stage II 64cc heads should be close to 10-1 compression. Only thing I need to do is bore the cases and the hard part done.







Stock 1200 piston in a 90" cylinder



Should be 100/100 motor when done.

With the 90" you really can't over bore it for a rebuild anymore but a 88" you can get 3 different over size pistons when it's time to clean up the cylinders.
3.8225
3.8325
3.8425

 

I would think that having a shop punch out the jugs would be the easy part.

 

+1 to NHRS!!!