I have a 2016 Road Glide Ultra with the Rushmore High Output 103" engine, I understand there's a difference in power and torque between to HO and the "Dry Head" 103". Is it due to my "Wet Head" or the cam or the tune or both?? Where did the extra power come from???? Thanks for any input.

 

All Rushmores are 103 "HO", wet or dry. I'm not sure of the difference but I believe it's the cam and compression (9.6:1 vs. 9.7:1). Not a lot of performance difference. 100lb/ft vs. 101.8lb/ft of torque.

 

The wet head motor runs a higher compression ratio (10.1 to 1 vs 9.7 to 1). Cooling the exhaust valve seat allows for the higher compression without experiencing pre-ignition (detonation).

 

10:1 compression

 

Thanks, I have corrected it.

 

Thanks for the quick input, now here comes another question. Same bike, 2016 Road Glide Ultra, already has Rinehart exhaust from the head all the way out, SE air breather and Vance and Hines FP3, any suggestions for a cam?? I normally ride 2 up, between 2,000-3,000 rpm's, rarely sees redline. Would like a cam that when it idles you can tell it does have a cam in it, but I don't want a cam that makes it unbearable to ride and lopes and crackles like a pro stock drag car. I heard everything from SE 211, 222, 251, 253, 255, 257. Woods 555, 777. Again, a little input from someone who has something other than a stock cam in their ride. Thanks.

 

If you really.......ride between 2000 and 3000 rpms, the 255 is a great cam for that purpose. Makes great low end torque, smooth idle, not too much valve train noise, but a little. great low end cam. If you plan on riding on the upper rpm range some its not the cam of choice for that. It will run up to 6000 rpms, but its really done around 35-4000 rpms. Should your riding style change......and it usually does, once start enjoying your new found horsepower, you may wish you had put a little more cam in it. Had a 2010 CVO SG with a 110, that had V&H Dresser Duals and 4 inch Rinehart's. It had SE 259E cams in it and it ran very good from 3000 up to 6200 rpms.
So you see its a trade off, you will give up one or the other, exhaust has a big factor in the project. True 2-2 systems make a little less low end torque, 2-1-2 systems make better low end torque. 2-1 systems make good hp, but can be pretty loud.
Lastly is the tune......it can make or break the install. A good tune will put a smile on your face every time you turn the right hand. A bad tune, with it going snap, crackle, pop, surging, and running hot, will take all the fun out of riding. Don't ask me how I know!!! Good Luck.

 

correct me if I am wrong but it is my understanding that the Rushmore touring bikes have the 255 cam stock.

 

No they don't. It's supposedly similar, but not the same.

 

Unless you have a radiator, you have 9.7/1 compression. The Ultra's do not have a radiator. Therefore, it is 9.7/1 https://www.cycleworld.com/2016-harl...-ultra-classic
only the Limited's and the CVO's, I believe, have 10.0/1 compression