I have a 2017 Softail Slim S and I decided to change the cams, which are the SE 259E cams. I also decided to do a head upgrade and bump the compression to 10.5:1. I left the head choice up to the dealership, and today I saw the heads for the first time and they are the SE Hurricane 120RX Heads. They look like they are waayy too much head for my 110! Has anyone else tried this combination with any success, or should I put them on the shelf for a latter day/build? Any help would be appreciated.

 

Unless your going to get the compression up higher put them on the shelf. It says your location is Denver so if that is correct I would not run them unless you get the static compression to 11:1.

 

Yeah Steve, I'm up here in this thin air and if it will wake up at 11:1, I will have the heads milled. Any idea how much I need to take off them to get it to 11:1?

 

I'd be interested in the heads you're removing,if you decide to change them.

 

I doubt if I sell the stock ones. If anything, I may end up selling the new ones.

 

One of the main problems with HD engines are the loose tolerances. If your going to get into it, when you disassemble it check the deck height before you do any machine work. The stock 110 engine were between 9.5 and 9.9 to 1 most of the time. So if your going to swap to 10.5 pistons you need to know where they are once installed to figure real compression ratio. Many times you will find the pistons are down the bore when at TDC so you need to cut the cylinder length just to get them up to the top where they belong. Once you get there, then your 10.5:1 pistons will really give you 10.5 or very close to it. Then you need to cc the heads and see how big the chambers really are to figure how much needs to be cut. The 259E camshaft is a mid to upper RPM camshaft and it doesn't like lower compression ratio's. Then where you live, and it's just not the best combination unless you get the compression up.

 

Thanks man. I decided to keep the stock heads and just shave .035 off to get the compression up and ride.