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[HD Street Performance]

I have a lot of experience with twin cam heads as they come off the motorcycles and most of the time I have the background data. What I have seen consistently and the majority of the time on the late models with SE 110 family heads are:

The tops of the stems worn and in the extreme cases a trough there. All of these are at <50k miles so far.
Both exhaust valves highly carboned on the stems and in extreme cases the rear beginning to or already seized.

The most recent are 120r heads one set with 15K the other with 28k. The set with 28K sometime has had a valve job and the K-lines replaced with the NOK viton, guides original, and the 15K set were untouched. Both showed signs of nearly seized rear exhaust valves and the 28k set the valve was not closing right. Both required a drift and hammer to get the rear exhaust valves out. I don't get too much into the forensics of the stem clearances because they are high from the inception IMO. All the CVO heads I process get new AV&V guides fit tighter and the geometry is addressed.

None of there situations had Roller Rockers used and I suspect it would have helped but not addressed the root cause.

One of the shockers to me is HD went to a lot of trouble and expense to improve the 110 heads on the 07 touring bikes with the program recall  and then incorporated these changes into the later models as part of the normal model run. Part of these changes were improved oil seals and IMO they are good (and very spendy). Then they release the 120r and Hurricane packages with the old K-line seals. The K-lines are not horrible but with valves this big, the geometry as-is out of the box, plus the valve to stem clearances that are typical it creates the "perfect storm" waiting to happen. These may be "race" motors but there is not one owner that doesn't expect to put some miles on one and do so with close to OEM reliability.

Sandunbar, consider your example and experience one from the right side of the bell curve based on what I have observed.

On a side note my buddy has a 06 SG with a 113", stock ported heads, 7mm valves intake is a 1.94", and it is pushing 60k now and will roll 130hp no problem still, the cam is the "jackhammer" TW8g, and last but not least it has S&S roller rockers.

[hogasm]

I have a lot of experience with twin cam heads as they come off the motorcycles and most of the time I have the background data. What I have seen consistently and the majority of the time on the late models with SE 110 family heads are:

The tops of the stems worn and in the extreme cases a trough there. All of these are at <50k miles so far.
Both exhaust valves highly carboned on the stems and in extreme cases the rear beginning to or already seized.

The most recent are 120r heads one set with 15K the other with 28k. The set with 28K sometime has had a valve job and the K-lines replaced with the NOK viton, guides original, and the 15K set were untouched. Both showed signs of nearly seized rear exhaust valves and the 28k set the valve was not closing right. Both required a drift and hammer to get the rear exhaust valves out. I don't get too much into the forensics of the stem clearances because they are high from the inception IMO. All the CVO heads I process get new AV&V guides fit tighter and the geometry is addressed.

None of there situations had Roller Rockers used and I suspect it would have helped but not addressed the root cause.

One of the shockers to me is HD went to a lot of trouble and expense to improve the 110 heads on the 07 touring bikes with the program recall  and then incorporated these changes into the later models as part of the normal model run. Part of these changes were improved oil seals and IMO they are good (and very spendy). Then they release the 120r and Hurricane packages with the old K-line seals. The K-lines are not horrible but with valves this big, the geometry as-is out of the box, plus the valve to stem clearances that are typical it creates the "perfect storm" waiting to happen. These may be "race" motors but there is not one owner that doesn't expect to put some miles on one and do so with close to OEM reliability.

Sandunbar, consider your example and experience one from the right side of the bell curve based on what I have observed.

On a side note my buddy has a 06 SG with a 113", stock ported heads, 7mm valves intake is a 1.94", and it is pushing 60k now and will roll 130hp no problem still, the cam is the "jackhammer" TW8g, and last but not least it has S&S roller rockers.

Now give us your incite on the 03-06 103SE motor since that is what the OP has and asked about

[HD Street Performance]

Those CVO 103s all have the same preexisting conditions. Same guides, seals, valve manufacturer, clearances, and geometry. One of the mitigating factors however that prevented issues with the CVO 103, my opinion again, is those were not stinking lean and hot as a 110 due partly to the cam being longer and mechanical CR being considerably lower.

[Hilly13]

I use roller rockers on .530 lift cams just so my valves go straight up and down when the engine is at high revs, the choice is yours to make.