Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[KBush]

Has anyone installed the S&S 128 big bore cylinder kit or the Suburban HD 130 cylinder kit?  I'm thinking of adding this to my stage IV kit but wants to ask if any members had any experience with either.  The one thing of note is the S&S is at 11:1 and the Suburban is either 11.4:1 or 11.8:1 depending on gasket. 

https://www.sscycle.com/products/m8-big-bore-kit-117-to-128-black-granite-with-highlighting-4250-bore-x-45-stroke/

https://www.suburbanharley.com/wisconsin-harley-davidson-service-performance-center--cylinder_kits-m8

[MCE]

2 cubes is somewhere around a 1% difference. Compression depends on the intended use, fuel quality, tune, elevation, camshaft selection, etc...

Keep the compression somewhat reasonable if it's a daily rider, and get the heads fixed. (2 cubes is nothing in the grand scheme of things) Fixing the intake ports will go allot further than anything else. Stock M8 heads are very workable and will serve you well if they're prepped properly.. 2 cents..

[hrdtail78]

What cam are you looking at?  The S&S kit at 11:1 work good and is designed around their 550 that has a 40 degree closing.  I agree with the above about 2 cubic inch's and would let cam dictate compression.

[MCE]

 

What cam are you looking at?  The S&S kit at 11:1 work good and is designed around their 550 that
has a 40 degree closing.  I agree with the above about 2 cubic inch's and would let cam dictate compression.

If you're going for maximum TQ possible, yes. Set compression on the higher side of the "range" specified by the cam. Otherwise, stay on the low side of the range.

Heavy bike, Two up riding, and performance goals are all factors. I'd avoid going to the max unless you're after every ounce of TQ.

Fuel quality, average temperatures and your elevation are things to consider as well.

2 cents...