I have 254e cams in my 2012 RGU. I like them. Had 255's in my 08 RG and liked them as well. The 254's seem to run a little cooler than the 255's but with a little less ''lope''. Cannot say for sure about mpg differences as my new ride has only 1800 mi and the motor is still loosening up.

 

I put the 255's in my 96" 07 FLHT with SE A\C, Rinehart TD's and PC-V and loved it! Liked it so much, started looking for that 100hp mark so did the 103" Andrew's 54 cams and Big Boyz heads (along with SE compensator a 49 tooth clutch basket to "fix" the gearing of the earily 6 speed). While the bike was A LOT more fun above 4500 rpm, I found for my riding style, I was rarley up there. Still have the 255's with about 3,000 miles on them and will likely go in the '12 RGC eventually.

 

Rodney,

No dyno for that special, just the generic stage two HD download map.....

I know everyone on here swears by the dyno tune, and I'm sure that if I had a tuner and a dyno, I would boost performance...... But right now, that would have put me into it for more $$$ than I wanted to spend.

 

I have the same gearing as you do and have no problems cruising at 2000rpm in 6th, so I'm not sure why you would sense any "lugging" at 2500. At 2500 RPM mine is very smooth and I actually prefer running a bit lower than that.

"Running out of steam" is something I hear every time the 255's are brought up in cam thread discussions, but usually it is uttered by someone who's never actually owned or even ridden a bike with them installed. You are the exception and I respect your opinion, but this isn't a sensation that I get at all. A properly tuned engine with stock compression and 255 cams installed will provide a very flat torque curve all the way to the redline. While it is true they don't produce as much peak HP as most other performance cams, "run out of steam" just isn't what's happening with my bike unless you are comparing it with another setup that has a peakier torque curve. Some cams produce a "band" that you can easily feel when it begins, sort of like what we used to experience with 2-cycle engines only not that extreme. Personally, I don't want a "band," but want the torque to come in equally throughout the RPM range, and that's what I and most others seem to experience.

It's hard to compared mileage since it will vary greatly depending on the environment (speed, wind direction, temperature, etc.), but if you're quoting highway mileage I'm about 10mpg higher than you. Even if it is city mileage you quote I'm about three mpg higher. How the tune is configured in the cruise range is an important factor in gas mileage. I'm running a relatively lean tune at cruise and can easily see 45-48mpg at moderate highway speeds.

Before comparing oil-temp readings it would be important to check the accuracy of your gauge. I'm not saying yours is not accurate but I've seen several HD fairing-mounted gauges lately that are off by 20-25°, although this admittedly wouldn't explain the difference you've seen between the two setups, and that's more important than actual temperature IMO. I run about the same as you (200-205°) in summer weather with the 255's, and I'm also running near-stock AFR's (14.5:1) in the cruise range. That said, the 255's might truly run a bit hotter because of their early intake close and relatively high CCP.

With the lugging, temperature, mileage, and weak top-end performance you describe I have to wonder about the tune you had with that setup or possibly the correctness of the cam installation. Just getting the cam timing off one tooth or experiencing crankcase sumping can cause the temperature, mileage, and performance issues you describe. I suggest this in good faith considering I don't hear most of the observations you mention here from other owners with this setup.

 

I've never felt the need to change the gearing on my bike, which is an '07 with the taller gearing. It is plenty strong in the low-end and midrange and I like the "long legs" at highway speeds. There is a zone between 55-60mph that I feel is a tad high for 5th and low for 6th and I usually don't cruise there when I have a choice, but it isn't a big deal. Anyway, if I geared it down that gap would probably move down a bit lower, but that likely wouldn't be much of a help. I've read the threads about the 68T sprocket for '08 Sportsters with IDS but have not felt the need to make this mod.

 

I've made that comment, and I've ridden several bikes with the 255 cams in them. Have you owned or ridden a 103/255 combination? I pulled them out of a friends 103 last fall because of detonation problems that he couldn't get tuned out, he finally gave up and went with 204s, which have proven out to be a great fit in the stock 103 bikes. On the other hand, I'm fixing to put a set in my younger brother's 96, because that's a particularly good fit.

The 255s will not pull as hard as some other cams in the higher revs, due to the ultra short duration. As motor speed increases, the length of time the intake valve is open decreases, and the cams don't have the duration needed to fill the cylinder. They're a lot like stock cams, in the higher revs, you can run them up to redline, but there's no real reason to. Just because you can run it all the way to redline doesn't mean it's making more power along the way. Ride a bike with a cam that's a little more balanced, and you'll get better than stock performance everywhere, not just in one area.


In some ways, I preferred the 103/se204 motor over my current 107/tw8. For a daily driver, it was hard to beat, the motor had a great idle, good street manners, quiet valvetrain, no oil blowby issues, and it felt very strong sop.

 

I have the 255's and have no problem running below 2500 RPMs in 6th gear. I question your map or install. Unless you are winding out the motor a lot, I think the 255's are a solid choice for the H-D touring bikes.

mikebaby

 

iclick

I have a 103ci engine and that will make a difference in fuel mileage, rpm's, lugging, engine temp. I ran the 255's for about 4 years and 30,000 miles in all kinds of weather, temps, elevation, city, highway, etc. I paid close attention to the fuel mileage after every fill up and also watched the oil temp. So I believe I have a good handle on it. I have an oil temp gauge (HD set with probe in front side of oil pan) in the fairing (which i had with the 255's as well as Feulings) as well as a digital one in the oil dipstick hole and compare them both. So I can say for certainty that the engine does run cooler, I get better gas mileage, and better torque. As far as gas mileage, for some reason where I live I get crappy gas mileage, but the Feulings have increased it from 33-35 mpg avg to around 40mpg in the same kind of driving conditions and same fuel stop. Once I get out of this state I seem to get better gas mileage, when I did an 8500 mile ride last year out West I was getting closer to 40mpg with the SE-255.

Running in 6th gear around 70 mph is about 2500-2600 rpms. With the 255's, while not exactly lugging, it just did not feel like it had any get up and go, i always had to downshift to get up and go, if I was going up a big hill, etc. With the Feulings it is way different. No need to downshift going up hills or to get up and go. Now if you really wanted to you can always downshift to get the rpms up higher to accelerate quicker. It seemed to me when I was passing and trying to get by a truck the 255's just lost the umph after 4500 rpms. Not so with the Feulings.

The torque curve is not flat on the 255's all the way to redline, at least not on mine per the dyno sheet. It is with the Feulings though. I have a ThunderMax on it it is always adjusting to the correct AFR ratio.

Every bike is a little different, every rider style is different, etc. I am just relaying my own personal experiences with the 255's vs the Feulings.

 

Had the 255s installed from new on my 2012 SG, price was in Ł so no real relevance to you..

Anyway I figured on the 255s quite simply as most riding in reality is up to 3000 rpm, we don't have hundreds of miles of straight roads here and its traffic city. Anyway it pulls like a steam train with top gear roll on from 70 mph to 100mph in the blink of an eye

If I needed more I'd buy a faster make

 

Ridden but not owned. My point with Mr396 was that given all the good reviews from 103/255 owners he seems to have quite a few issues that might point to an installation or tune problem. Hot running, sluggish performance at higher RPMs, and sub-par mileage are classic symptoms of sumping. You have to admit that the vast majority of 103/255 owners are very happy, and few have moved to other options, that observation being based on on quite a few testimonials here and in other forums. It might also be pointed out that there have been a few that have moved from other options to 255's, too.

In the past we've also discussed your riding style vs. mine. You are a more aggressive rider and don't want to compromise power in the top end, while I'm quite content keeping my RPM's below 4000. Neither of us is wrong in what we want, and everyone must determine their own priorities.

I'm sure it is, just as there are quite a few other options for the 103. I know of no one with the 103/255 in this area who have complained about detonation, and none have hot-start issues either. Detonation can usually be rectified in tuning.

The OP may indeed want something other than what the 103/255 offers, and he's doing the right thing by asking and taking the time to research the topic rather than let some dealer make the decision for him.

I make these general points every time this topic comes up here, and IMO what you say is true. I'll emphasize the last sentence above that there may indeed be no real reason to rev the engine past 5k RPM in a real-world scenario. On paper the 255s may look unimpressive with specs that just don't point to improving performance, especially those who are accustomed to seeing specs that emphasize peak HP rather than usable torque. But the reality is that they do work effectively for most people in the real world, and these are touring bikes, not racers.

Compared to stock and everything else being equal the 255's produce more power across the board, even at the redline. So to me that's making "more power along the way." Although the emphasis is below 5k RPM, it is still outputting more above that than you have with the stock cams--just not as much as most performance cams will provide. It's all in where you want the power.