103 Stroker engine

[jr0b]

Mike
I have an 02 Screaming Eagle Road King with the stock 95 in engine. I have added V&H ovals, SE air filter and reprogramed it with the SE race tuner. I have an opportunity to purchase a new 103 SE Stroker (19144-03). The catalog states that the engine fits an 03 Road King. Will the engine work in the 02 RK? Will anything have to be modified or changed to make it work? Any suggestions to increase the torque?
thanks
Jerry

[Mike]

The engine was emsissions certified for certain models only and, as a replacement, it can only be listed for those models. It will directly bolt into your 02. The length and location of the crank sensor harness plug changed and you may have to modify that portion of the harness (I cannot remember what year that changed). With your SERT, recal to suit.

As an 03 part number, the engine will have SE 253 cams installed. Changing these to the 255's will dramatically increase tq from 2-3K rpm. Top end power has proved similar between the two (with the 253's having a slight edge from 3.5K on). The 255's now come in the SE 103 and 110 engine kits. Mid range tq (3-4.5K) and mid/upper end hp (3.5-5.5K) can be improved with 251 cams but with a loss of low end tq (2-3K). Better with increased compression. Less of a problem with a 5 speed bike vs 6 speeds. Downshifting also improves performance when setup for mid range tq.

The 255's and 253's have the same base circle and would be direct replacements with no pushrod or other part changes. Tuning with the 255's is critical to prevent detonation and you may have to do mapping adjustments to accomodate riding style and environment (even if custom mapped).

The 251's and 257's require longer pushrods. The 251 could get away with the stock compression but would perform better with 10-10.2 compression. The 257's would be lazy without a compression increase to 10.2-10.5 and so both of these would be recommended along with piston changes.

The V&H ovals will complement the 255's well. If you go after midrange tq (251/257's), a good 2-1 would be better.

Your first decision will be to identify exactly WHERE you want the "increased torque", rpm wise. Then make your cam choice also considering cost. The 255's would be the least expensive option.