I would consider doing a 117cu build 1st.

Fast motor.

 

There are a couple dudes running Jim's race motors. They get some amazing runs out of those bike. Mind you they are mounted in drag frames.

Plus they get a 1 year warranty with the 121 race engine. That in its self says something.

 

The motor was built 9-10-09, don't know what is considered old. Motor runs smooth, no noise. If I try to feed it anymore fuel it just runs to rich. Not getting enough air makes sense to me. We'll see.

 

[quote=The Lost;6102535]I put a 131 on a 2002 Heritage. I have 2,300 miles on it now and put it on the dyno this week. The torque numbers were real good, 141 lbs. But the hp numbers were a little disapointing, 117 hp. I have a 48mm Mikuni carb on it and the only way the tech could get the fuel air mix right was to install a smaller jet than came with the carb. He had to go to a 170. The smallest that came with the carb is a 190. He claims the carb is to small to feed enough air. I'm running a S&S intake, R&B header pipe. He claims I need to convert to fuel injection. Don't know if I'm ready to cough up another 2 grand to do that. Other than that I'm tickled to death with the motor. The fuel usage is the biggest surprise to me. With the wife and I running 70 mph it'll get 41 mpg. My old motor which was a heavily built 95 got way less, about 30. I forgot to mention this motor makes 125 lbs of torque a 3,000 rpm, that's killer. The motor was built 9-10-09, what's considered old?

 

YEAH, send some of that CASH$$$$$$$$$$$$$$ my way!!!

 

Jim's reputation speaks for itself,and as long as these motors are properly maintained,and not neglected,they should last almost as stock.Transmissions can be beefed to handle the extra power.Zippers for one has the capability,I'm sure Jim's must do the same thing.Power/Torque, from a 131" should put a smile on anybodies face that could not be slapped off.Both my RK's are powered by big inch motors,no noticeable increase in vibration.I would ride both of my machines coast to coast and not give it a second thought.Again it is all about how any machine is treated and maintained.One last thing the is VERY IMPORTANT.BRAKES!!!!! make sure they are up to the task and you know how to use both wheels together.