Hello👋 Need some advice people

I have a 2016 FXDLS that I would like to get some more power out of. Just discovered the crank runout is .007

Rebuilding the crank is quite expensive to get done where im from so im considering just buying a new one from Darkhorse.

The current set up is: (Done by previous owner)
S&s 585 cam
Portede heads
58mm TB
5.3 injectors
Fab28 exhaust
+ Tune

At first I was considering the SE117 kit that just bolt on but I've read a lot of mixed opinions about it...??? With the thin wall and some saying it's prone to running hot

Then i was thinking since im splitting the case I could have it bored to fit a S&S 124 kit with a 4.625 crank
but I've also read that wouldn't work with the 110 heads because of them being 95cc and compression would be too low.

I really don't now what to do??? I just think I would be a shame to getting a brand new darkhorse crank and timken conversion just to put the stock 110 cans on again..

So what would you guys recommend?

 

At 124” and 95cc heads, you could use a cam like the SnS 585 and flat tops or if wanting a larger cam - find a + cc domed piston, they do exist for heads like yours

 

With an S&S 124" cylinder kit and an S&S 4.625" wheels with. 000" piston to deck height this kit would produce 10.75:1 compression even with your 95 cc heads kit.. What wrong with that?? If you need more you can always deck the heads..

Pistons, cylinders gaskets and a set of wheels would be around $3400 plus the labor.. you can still use the 585 cams and the 58 mm T-body. That setup will yield very good power.. But remember power is truly made in the heads...

 

Just FYI, a .007 runout does not dictate a full build. Sure you are limited to chain drive cams vs gear driven but other than that you are good to ride it as is, so unless the runout is continuously growing meaning you have a known problem, don't feel you need to tear it down.

Now if you just want more power just to have it and are using that as the "man excuse" to justify a full build, then I'm all for it. Lord knows I've talked myself into plenty of big purchases that weren't otherwise justified. I just wanted to make sure you weren't being told by some mechanic that the motor is shot for no reason.

As to how to build the motor, Id say first understand what you are really looking to gain. That is a nice Dyna and the set up you currently have is usually a lot of fun in the upper RPMs especially on lighter bike. Are you looking for more top speed, more power earlier on, quicker 1/4 mile times, or just want to win in the bar stool HP shootout conversations, etc. Could the better option be changing your gearing up or down.

 

Honestly I think the stock cam plate allows for more and more run out as time goes on. Only because there is no real bushing or bearing to support the pinion shaft like the Evo's used to be. With that I would suggest getting a camp plate that has a bronze bushing to help control the wear of the cam plate so the pinion Shaft won't go further out. I have documented with videos on YouTube using the S&S cam plate with the TC3 pump where my run out has actually gone down from a heavy .0055" thousands of run out to currently now 0.0045" of run out..
@Jake707 is correct .007 is not crazy out for A Twin Cam..

 

If you decide to build a 124", there are things you need to know.
(1) Darkhorse uses rods that are 7.670" long.
(2) To have a zero deck use the S&S Cycle 4.125" bore for 4.625" stroke cylinders that are 5.013" long. Don't use the 5.004", you'll have the piston out of the hole. The 5.013" cylinders and the Darkhorse 7.670" rod length will get you at 0.000" deck or very close. Also use a base gasket that is 0.020" thick, preferably a Cometic SLS.
(3) To feed a 124", just go with cams that are designed for that, either an S&S 625 or an S&S 640. The 625 cams will give a broad power range. The 640 cams will be more mid range and upper RPM.
(4) Use pistons that have a dome designed for the CVO 110 heads. CP has a 2.4cc domed piston that will do the job.
(5) Heads, of course find someone to port them for a 124" motor and the cams you use.
(6) Cams, the S&S 625 cams, set the heads up at exactly 95cc, use the above pistons, and an MLS head gasket that is 0.030" thick. This will give you 11.1:1 static compression, and a corrected compression of 9.7:1. The S&S 640 cams, set the heads up at exactly 93cc, use the above pistons, and a MLS head gasket that is 0.030" thick. This will give you 11.4:1 static compression, and a corrected compression of 9.6:1.
(7) Tuning, the above compressions will work and tune decently. The 124" motor can stand more compression, but the tuning would need to be dead on perfect.
(8) To feed the motor you will need a larger throttle body. A 58mm throttle body will be fine. I run an HPI 62/64mm.
(9) Exhaust, I prefer 2 into 1 exhaust. My favorite for big motors is the D&D Boarzille. They're very loud, but will get the gases out of the motor and maintain a strong low and mid range, and will get you lots of upper end power.

Building a 124" takes some thought and investigating as to what parts will fit your needs the best, and as you know, the cases need to be machined. Also you will need $$$$$$$.

S&S 640 cams



S&S 625 cams

 

That's real good advice... I know Scott was setting up the 124" almost identically... He preferred the 640..

 

@Ohio HD Do you know the part number for that CP piston? I'm looking to do this exact build. The only CP 124 piston part number I can find is BHM124FT, but that's a flat top? Thanks!

 

Contact Randy Torgeson at Hyperformance. Randy stocks several CP pistons with a large dome for standard TC and 110 heads. He needs to know what your building, what the exact cc's of the heads are. Tell him exactly what you want as far as static compression. He'll machine a set of piston domes down to your needs. He's a wealth of knowledge and a really nice guy. I've done a lot of business with him.

https://hyperformancemotorcycle.com

 

Thank you @Ohio HD . Talked to Randy, he's a great guy!