Ok, here is the deal... I am building my 09 RK this winter. My original plans were to do a 116" with the S&S 4 5/8" crank. I have purchased this crank and now I'm debating on going to the 4 1/8" pistons (124") instead of the 4" (116") I have discussed my build with Hillsidecycle (Scott). I need to get some opinions from the masses. I will either have headwork done through S&S or have Scott do them. I realize Scott's work would perform better, but I get a great deal at S&S because of my motocross sponsor. I will have HPI do my throttle body and install the 5.3 injectors I already have. I will be running a LSR 2-1 exhaust and have it tunned by Fuelmoto with the Power Vision when complete. I do have a limited budget but plan on having the cases bored to accept the bigger pistons down the road if need be. My questions/options are:

116" with S&S-worked heads: this is the current plan just because I know the S&S ported heads "can" handle the displacement....

124" with S&S-worked heads: at a couple-few hundred more, here is the problem, will the heads done by S&S flow enough for the bigger displacement? Would I need 6.2 injectors? Would my rivera primo variable clutch hold the power? Chain drive a neccessity?

116" with Scotts heads: More money than I would have in the previous 124" build but headwork would be superior.....and I'm guessing gas mileage also.


Obviously the more money this takes, the longer I will lose ride time in the spring. I am an averaged sized guy 5'11" 170lbs and I will most likely ride this thing HARD! and use it to commute. (I am after all a motocross, ex sportbike guy) I also would like to get opinions on if my belt will hold any of these builds... I'm not large and my wife is a slim 120lbs so not much weight, but I garuntee I will launch and wheel stand this thing.

Any and all thoughts are appreciated. Thanks.

 

I had a S&S 124" crate engine that I had Scott, at Hillside, do the head work and increase the bore size from 4 1/8" to 4 3/16" yielding me approximately 128 C.I. Engine is putting out 144 TQ. This on a heavy bagger. I do allot of 2 up riding. So the total weight of me, wife, and bike is 1,255.00 lbs.

That said the belt did not hold up. I changed over to chain drive and all is well.

Go 124 C.I. and have Scott do the heads. More the better and it's never enough.

 

Save yourself a couple of thousand; SE120R. Keep your OEM motor on the shelf, just in case; or sell it for $1000-$1500 to recover some of the build cost. Severa in my area have converted, all touring models and all very happy with the upgrade.

 

Oh boy, I knew that I would hear that! Ultimately, if I wasn't on such a budget with a new baby on the way, I would do that the first time. Unfortunately I'm not sure I can squeeze that out. I'm sure I would aslo need to go bigger on injectors/ clutch/ and throttle body, which starts to add up!

 

Abesolutely though about this, but I love the idea of having a sleeper... My brother-in-law is putting a 127 ultima in his softail. While I know these motors will not compare to that one in a lighter bike, I want him to say WTF! you didn't just do cams, lol.

I'm actually really sold on the S&S crank, I will abuse this thing and the last thing I need is the bottom end going out... I'm sure the 120R is a great motor, but why not get the best while you are getting....plus there are no badges saying 120" on these builds...

 

Well... I agree with djl, and If you're working with Scott, I'd follow his recipe to the letter.

As someone else said, SE120R represents a great value and Scott could help you tweaking / prepping that too.

Finally - you go big and there's no cheap way around it. You're going to have to address intake, exhaust, driveline if you want to get everything out of the motor. Maybe brakes and suspension too. You can pay now or pay later -- but you'll pay, and if you ride hard, you'll pay sooner.

What you might do is think in terms of phases. Get the motor squared away and ride it easy until next year - or whenever you can get the clutch, exhaust and other bits. You could also stick with whatever intake and exhaust you have and be done with it. You're still going to be north of 125/125 -- so what if you leave some on the table? However - whatever way you go - you will need a good clutch. If you twist it all the time, you'll be needing sooner rather than later.

Between the choices you list they're all good. I'd go as big as possible right from the git-go and be done with it. S&S 124 is tried and true. A little mojo on the heads and they're runners. Ditto the 120R - not hearing any complaints at all. Outfit them with rollers, a little head work and you're good to go... If the dollars are close, I'd go S&S 124 - and you might check around, as there are deals out there. JMHO.

 

Yeah this is what I am thinking. I am already committed the S&S route as I have the new 4 5/8" crank in my basement... How do you think the 124" with S&S worked heads, HPI worked TB, LSR 2-1 exhaust, and rivera primo variable pressure clutch would hold up? Would I be able to put the power to the ground on that clutch? need bigger than 5.3 injectors?

 

The S&S crank is not welded; if you intend to abuse it, suggest you have it welded. Don't be lulled into the fantasy that just because it has S&S on it that you can't tweak it.

 

I'm not that gullable..... I talked to R&D at S&S and the guy holds land speed records and has personally abused three diferent motor setups with the 4 5/8" stroke crank from S&S and he weighs 255 and pulls the front wheel everytime he rides... Never an issue whatsoever. I am intelligent enough to realized when someone is being a salesman and when someone actually beleives what they are saying. I asked them to weld my crank at S&S before they ship it and two seperate people told me not to waste my money. In 7yrs of their personal time answering service calls for S&S, only 2 have ever scissorred or turned (to their knowledge) and they were fixed by S&S. I like companies that stand behind their product. After racing at the pro-am level, I dont have time to to just believe what people tell me without using multiple resources for research. Having said that this is my first v-twin build... if I grenade it then, I'll just have to go bigger! lol

Thanks for the input so far guys, keep it coming! Still waiting on clutch and driveline answers in reference to the 124" S&S worked motor.....?

 

go big the first time out: 124 with mild head work will get it done. It would probably be wise to swith over to chain drive while you have it apart--if your inclined to do wheelies and/or rolling burnouts the belt will not last.