I have an ‘18 RKS and had the dealer install a stage 3 kit. It’s pretty good but was contemplating upgrading to a 124” big bore kit from S&S. I contacted Moonshine Harley Davidson because they are well known for their performance upgrades. They suggested I keep the stage 3 and port the head from Branch, add a HPI 62 mm air intake, cam change to a Feuling 508 or Andrews 504, S&S oil pump and cam plate, and add an AIM clutch. Thoughts ? It is about $1,500 cheaper to go this route than the big bore (with installation) but is it going to give me the same pull?

 

Short answer is no. Don’t add all that to a 107ci. Your gains from bumping cubes is no contest. Spend the money get the easy 140/140 and don’t mess w the small stuff. Those guys must be drinking the moonshine

 

Lol well it’s a 114 with the stage 3...big bore is that much better?

 

If you want power for your money the heads and tbody and cam swap will gain minimal and being an upper rpm move you’ll probably like it less on the street. Cubes are guaranteed value, Ive rebuilt a 124 to 131 with no other changes and gained a chunk of torque low/mid range. Btw if you haven’t noticed those boys aren’t to bright over there at moonshine, their YouTube channel is a joke, bunch of assclowns

 

I agree with Dave, more torque to be gained by adding cubic inches, all of the other stuff they are trying to sell you is "well........since we are in there...." and all that does is drive up the bill.

Check out Sheffer performance's Facebook page, Daren is doing a fair share of these M8 big bore kits and getting some good results. Pick up the phone and talk to him, great guy to deal with. He can help you get it all sorted out

 

Don't use Branch.. Nothing but probelmswith there stuff after O'Kief took over.. You shop don't know nothing..

 

Steve at GMR would be another good person for you to talk to, he is also doing some good things with these M8 engines, he is in Texas so may be in traveling range for you

Scott at Hillside and Kirby at Vee Twin are good guys to deal with if you do the work yourself or have a local indy you work with

 

Listen to the previous posters. A solid 124" will make you wet your pants and it ain't even working hard. Your dealer is drinking the moonshine and smoking monkey weed.