Hello everyone from Alabama new to the forum and the Harley world switched over from a sport bike but I have a 03 road king classic and was thinking about doing the fueling 525 cam chest kit but have since decided to just go with a big bore kit that comes with cams, cylinder, pistons and everything you need I was looking at the S&S 100” big bore kit but I wanted to see what other peoples ideas are on what to do in order to get more power from this motor…..I just like the idea of buying a whole kit so everything is included

 

Bring new to the Harley world, you need to know that increasing power from the TC88 motor has many levels and you are standing just outside the entrance to the "rabbit hole". The kit approach is a reasonable way to approach and increasing displacement via a big bore kit is probably the best place to start but that's what it is, a start. Once the "new" wears off, you will be wondering what if I had included head work, or cams, or both in the plan; and on it goes. I don't know any member of this or other forums that starte with a big bore kit and did not venture further down the rabbit hole.

No mention of mileage and it would be advisable to replace the spring loaded cam chain tensioners with a set of CYCOs and replace the inner cam bearngs with a set of Torrington/Koyo B148s, full compliment bearings.

You did not mention if the bike is carbed or EFI which is also a factor; if EFI you will need a fuel management system and if carbed you should include a programmable ignition in the plan.



S&S offers a 100" Power Package that has everything you need to build a pretty powerful motor, capable of easily making 110TQ/110HP, more with a well thought out plan and even more with head work but at $3K and change, might be more than you are prepared to spend but will be less than you will spend going at it piecemeal to satisfy your want for more power.

The best advice I can offer is to consider how you ride the bike, how much power you want and if "more power" means more torque or more horsepower. i.e more low and midrange power or more mid and upper range power and how much you are willing to spend. Take your time, get educated from local builders, some members of this forum and don't get in a rush.

 

I should have included all of that in my post but it is fuel injection and it has 22,000 miles on it but I was going to order the S&S 100” big bore kit and also putting fueling 543 cams in it I am wanting good torque but also want to be able to cruise interstate as well I was going to change the hearing a little bit so I have lower rpm’s and a higher speed but hoping with the mods to the motor am hoping to produce enough power to still have plenty of torque I am wanting to stay around $3,000 — $3,500

 

That kit is 10.5 compression, you’ll have problems with a cam that small. Exhaust is something you need to figure in too, fishtail duals not great. Also figure around 750 for tuning the fuel injection.

 

True the 585 easy start cams that come with the 100” S&S kit will do the job going to change the fish tail

 

JMHO, but the Fueling 543, or any cam with an intake close with a 43* intake close is not going to perform well; not enough CCP. A cam with a 25*-30* intake close will perform much better; there are severla that come to mind but the Andews 48 would work well. Regardless of cam choice, any cam with lift higher than .510" is going to require replacement of the OEM valve springs; they won't accommodate more. Some have gotten by with .525" but, for me, that would require mock up and checking piston to valve clearance. The fact that you are thinking about the Fueling 543 tells me that you need to further educate yourself so you can put together parts that "play well" together.

You will need fuel management and a dyno tune to maximize the benefit of the upgrade. Your current exhaust system leaves a bit to be desired from a performance standpoint as well but that's another story.

If you are doing the wrenching yourself, you can build a pretty salty motor for $3500; that would also cover sending the heads out for porting and set up for the selected cam.

 

25-30 degree intake close with 10.5 compression isn’t a good idea, the 585’s will work fine. I’d choose a long 2-1 pipe.

 

I went nikal sil rev perf 98". Then it cost almost as most as new S&S kit to get them redone and get groves out. I decided against S&S 100" kit because of compression. In hot alabama you may want to talk to other people. I just bored my stock to 95". When the need work, I will bore 10 over.

The 100" jugs with a different came, flattop pistons may be an option. I can't remember what pistons they had.

I did thinner .03 headgasket, but that also raise compression. James makes a .035, which is interesting. I believe stock is .043, or .040. Raising compression is harden on engine, needs a better tune, and better gas, which can be issue in some areas. Lots of people run high compression, I don;'t

 

If you’re wanting to get the best value for your money I would bore the stock cylinders to 95”, to free up funds for other things you need. The tune and exhaust are 2 critical pieces that matter more than five cubic inches

 

bore, cams, ports. Will also cool the bike down.