Help needed with a Cam choice
So, here I am again faced with which cams. I would really like to stick with MOCO offerings so I ask for opins on the 255 or 260 cams. HOWEVER, I do read these threads and see alot of info on Woods and Andrews but don't know anything about the cam choices.
My ride style is shift fast and get to cruise without hitting 6000 rpm. Bikes current set up is: Stage 1, SE AC, SEST, VH true duels with monster ovals. (I do know that the true duals rob low end, but I really wanted them this time) so I know the exhaust set up will not make the most out of the 255's but I am willing to deal with that.
Thank you for your input, knowledge and for not beating me up. I HAVE searched all the threads and look up to find myself reading posts from 2006 on 211 Cams.....
Peace out
I've got SE204 along with 1.725 rockers in my bike. They're similar to the Woods 6, but with a slightly earlier torque profile. Either way, you get good overall performance, and a bike that's lots of fun to ride.
As you've probably seen, there's lots of guys who are passionate about their se255 cams. They are in my top three cams for a stock 96, but I think the higher compression of a 103 makes other cams not only viable, but more desireable. However, there's lots of 103s running around with SE255 cams in them, and just about any tuner you find will have experience with that configuration.
Last edited by Mike; Aug 9, 2010 at 11:15 AM.
Also what seems to be lost in these conversations is the cost factor. You can buy these easily as CVO pulls for $150 or less, and an upgrade can be made for ~$200 if you DIY and have the proper tools. For this outlay they are a bargain DIY performance upgrade, perhaps the best available for the money spent. Can you do better by throwing more money and mods at the motor? Of course, but I didn't want to do that.
Anyway, I would still repeat the statement of Mike Stedman of Latus HD that "No cam can beat the 255's to 3500rpms." That's his opinion, of course, but he's a knowledgeable source.
No problem on the concern that I'm offended, as I'm not, and don't take any of this personally. I engage in these conversations because I always learn something in the process. I appreciate your thoughts on the dynamic processes involved in cam engineering, as I consider this a very complex science that I don't fully understand.
I have ridden many Harleys at all levels of the performance spectrum and I'm very acquainted with what you are describing, but that's not what I want for my bike. For one thing I don't want to invade an already good-running engine, nor do I want to spend more money on performance upgrades. I'm aware of what can be done but I don't need it, as I'm happy where I am.
so who was missing who's point again????
I don't think we disagree that much on this topic but rather have different ideas on what a cam-upgrade should do to make us happy. Where we do differ slightly is that I think typical 103 compression (~9.6) is ideal for the 255 cams, while you think it is a bit high. Okay, fine--I haven't seen any evidence yet that this wouldn't work well, and they do work fine (i.e. no CR's) for most people who have installed the full SE Stage II kits with 10:1 flat-tops. I also differ with you on typical HP/TQ numbers, as I've seen at least four charts for stock TC96/Stage 1 where they hit 100TQ with HP in the low-to-mid 80's. Some do chart lower, but I would submit to you that this is a tuning issue, and that with a good tune they will hit the numbers stated above in a stock TC96/Stage 1.
Last edited by iclick; Aug 9, 2010 at 03:14 PM.
I will add that when I was running the standard 103" BB kit, with the 9.5:1 compression, the bike seemed to run a lot smoother - I just got greedy over the Winter. But I have to admit, that due to the high compression, I'm getting some pinging in the 2700-3000 RPM range in 5th and 6th gear that can't be entirely tuned out. My compression numbers are really high now with the head work and SE-255's.... in the 225-230 psi range. It's got to be corrected.....
I must disagree. Many have replaced cams on a Stage 1 TC96 with 255's and have been very happy, and I'm a member of that club. They do very well with the stock 9.2:1 compression of the stock TC96 and no other mods, and it is the best bang-for-the-buck upgrade on a stock motor you can do if your quest is increased TQ where most of us ride, IMO, especially if you DIY and buy a low-mileage CVO pull.
As for "running out of steam" at 4500rpm I must respectfully disagree with that notion too. They produce a very flat TQ curve and make power all the way up to the extended redline (6250rpm) with no "hitting the wall" or perceivable drop-off in the process of getting there. They do not produce prodigious amounts of peak-HP and it is not their designed purposed to do so. These cams do not have a "band" where you feel a surge at a give point in the transition toward the redline, which is why may be why some suggest they "hit a wall." That's not the sensation I get when riding my bike, although I'll admit that I live above 4500 rpms only rarely, as the power is more than sufficient below that point, for me anyway. They do produce more peak-HP than stock, but not as much as most other cams on the market. For this reason they would be a poor choice if drag racing is your priority, but for real-world power where you ride I don't think they can be beat for the money spent.
Last edited by Heatwave; Aug 23, 2010 at 10:04 PM.
Last edited by bluegrassboy; Aug 23, 2010 at 10:00 PM.
You cite the HD literature, and you must look at their charts in context (see attached). First, it is a "street legal" tune, which is the HD download, and the dyno-chart is obtained with SE mufflers, not the most free-flowing on the market. Even under these sub-optimal conditions the HP peak is around 5k and at 5500 rpm there is very little reduction from the peak. Looking at that chart, which is obviously not a reflection of what the cams can do with a good tune, it is producing about 8hp more at 5k than at 4k, so I don't know where you get the "dying above 4000 rpm" idea. If you look at any of the dyno charts resulting from a good tune you'll see that HP peaks at ~5200 and the torque curve is much flatter, typically holding TQ above 90 from 2500-4500 rpm in a stock TC96.
The 255's are torque monsters below 4500 rpms and the key to riding with them is to run where they work best. In fact, some say changing your riding habits is necessary. I almost never exceed 4500, and I don't need to go beyond that point since the power is available below it. I've said repeatedly that if you want to drag-race or you otherwise value peak-HP the 255's are not the right choice for you. Something else I've said repeatedly is that "you don't ride dyno charts."
Last edited by iclick; Aug 24, 2010 at 11:31 AM.
The Best of Harley-Davidson for Lifelong Riders
You cite the HD literature, and you must look at their charts in context (see attached). First, it is a "street legal" tune, which is the HD download, and the dyno-chart is obtained with SE mufflers, not the most free-flowing on the market. Even under these sub-optimal conditions the HP peak is around 5k and at 5500 rpm there is very little reduction from the peak. Looking at that chart, which is obviously not a reflection of what the cams can do with a good tune, it is producing about 8hp more at 5k than at 4k, so I don't know where you get the "dying above 4000 rpm" idea. If you look at any of the dyno charts resulting from a good tune you'll see that HP peaks at ~5200 and the torque curve is much flatter, typically holding TQ above 90 from 2500-4500 rpm in a stock TC96.
The 255's are torque monsters below 4500 rpms and the key to riding with them is to run where they work best. In fact, some say changing your riding habits is necessary. I almost never exceed 4500, and I don't need to go beyond that point since the power is available below it. I've said repeatedly that if you want to drag-race or you otherwise value peak-HP the 255's are not the right choice for you. Something else I've said repeatedly is that "you don't ride dyno charts."
With all due respect, the torque curve for the 255 is anything but flat. It's strong upto 4000 rpms and then it plummets. In every dyno I've ever seen where a bike uses the 255 cam, the ft-lbs drop off at a rate far greater than most other cams. That is the trade-off this cam design makes in order to move the torque curve lower into the rpms. Even the HD dyno you just included in your last post proves that point.
Here's the dyno on my stock 110 with the 255 and it performs just as the HD catalog shows this cam, it literally falls off a cliff at 4k rpms. For alot of guys that works just fine since they typically shift before 4000rpms. That's not my style and anyone that has an upgraded engine is generally looking to "have their cake and eat it too", meaning both low end performance as well as HP builds out to the limiter and TQ that holds on for as long as possible.
The 255 does NOT achieve that end. For the modest or stock engine that isn't going to breathe well above 4000 rpms anyways, then this cam may be just right for the guy that shifts early or does alot of riding 2-up. If you can show me any dyno graph where a 255 cam "pulls" all the wait to 5+k rpms, I stand ready to learn something new. Otherwise I stand by my comment (and HD's dynos) that the 255 cams dies early (4000rpms) and fast.
Last edited by Heatwave; Aug 24, 2010 at 12:32 PM.




