Cam Change
Harley EvoDiscuss Cam Change in the Motorcycles forums; I did a Stage 1 upgrade this past winter to the Fat Boy. It had 22,000 miles on it when I bought it 4/07 and now has 33,000. Stage 1 ...
I did a Stage 1 upgrade this past winter to the Fat Boy. It had 22,000 miles on it when I bought it 4/07 and now has 33,000. Stage 1 performance was better than stock but not that noticable. Next I removed the stock CV carb and after many suggestions from other members (Thanks Frisco) I installed a Mikuni 42. It used to flatten out @ 100MPH and now still pulls @ 105. I'm not looking to go much faster- I want to achieve 105 with authority. Time for a cam change. Is it worth doing it myself? I don't have any of the special tools needed to R&R the bearings or bushings. I've read that the bearings (rear) were junk during this and other years. Mine is a 96 and I don't believe it has been changed. Other than this I believe I can handle the task. Any suggestions, thoughts, ideas or past experinces would be greatly appreciated. If there are other components that any of you suggest I upgrade @ this time, please advise.
I did a Stage 1 upgrade this past winter to the Fat Boy. It had 22,000 miles on it when I bought it 4/07 and now has 33,000. Stage 1 performance was better than stock but not that noticable. Next I removed the stock CV carb and after many suggestions from other members (Thanks Frisco) I installed a Mikuni 42. It used to flatten out @ 100MPH and now still pulls @ 105. I'm not looking to go much faster- I want to achieve 105 with authority. Time for a cam change. Is it worth doing it myself? I don't have any of the special tools needed to R&R the bearings or bushings. I've read that the bearings (rear) were junk during this and other years. Mine is a 96 and I don't believe it has been changed. Other than this I believe I can handle the task. Any suggestions, thoughts, ideas or past experinces would be greatly appreciated. If there are other components that any of you suggest I upgrade @ this time, please advise.
Thanks to all and safe riding!
1996Fatboy (Fat)
I went through this with my Sportster. Wanted more power so I got a good cam. Then that reduced cranking pressure so I needed more compression to make it all work best. Then I needed the ignition adjusted to match the new flow. But the H.P. is there if you cover all the bases. You can raise compression with the heads or pistons or both, and you need some sort of tuner for the ignition. Then you should have all the power you need with out giving up reliability. A dyno helps here for the sniffer to dial in the A/F ratio.
As mentioned in numerous threads/posts here your engine (EVO) reacts WELL to relatively simple modifications..like "mild" recamming..due in part to it's adequately flowing etc heads. I went with an Andrew's EV-27 in mine..and,am very satisfied with the torque & rpms gained (wide power band) over the stock cam. Yeah,and the installation was relatively simple too...noting this was my 1st. HARLEY recamming project.
There's only one cam to contend with. And the only special tools you may need are a inner-cam-bearing puller/installer @ aprox.$200**thru JIMS..noting some guys have gotten the job done with just a blind bearing puller AND the orig. cam to drive in (carefully) the new TORRINGTON bearing,that you should replace your stock one with anyhow...if only (?) for longevity.
Some guys will diddle (?) with guaging back-lash with the new cam gear and R&R their crank/pinion gear (if necessary) to get that just-right. But a much simpler & cheaper way to get the best results would be to take both cams (new/orig.) to a reliable shop and have the press-fitted new cam-gear R&R'd with the orig. cam gear that's already "mated" to your crank/pinion gear.
A set of adjustable push-rods @ aprox.$150** would save you a LOT of labor/grief over R&R'ing the stock solid push rods that could be simpley cut (bolt-cutter) out of there. And,the only other parts (other than gaskets) you'll need would be a set/variety of cam-shims to get your end-play w/in spec. of say .010"-.015" or so.
As for re-tuning ?? No big deal,either !! You may want/need to do a little rejetting/adjusting of that Mik (nice) 42..but,since your engine still has the ign. pick-up in the nose-cone,you can still advance/retard (if deemed) manually (so to speak) with NO "remapping" and/or "dynoing" ETC required.
You may want to go with a little "hotter" cam...like (example) an EV-3 for a bit more on the top-end than bottom-end W/O going TOO far from what you seem to be interested in. But as long as you stick to the "bolt-in" cams..installation is virtually the same...and WELL worthwhile IMO anyhow !!
__________________ "If at first you don't succeed, try again...then swear"
Mark Twain
Thanks for the replies. I'm hoping to get this done before Gettysburg Bike Week so I can relax and consume some "Twinkies". Only have a couple of weeks left so I need to make up my mind what cam to use. Screamin Eagle or Andrews. Both seem to be good choices. Maybe I'll wait and see what deals there are at Bike Week. Decisions,decisions! Life is Good!
An Evo with a bigger cam will like a final CR of 10:1 and run just fine on premium pump gas. I have a SE 57 cam with SE heads in my FXR4. Good combo but if you go with the stock or semi stock heads a lower lift cam would probably be better. SE ign. module is good but I think it's best to have an advance curve that matches your cam and projected riding style. Harley did a lot of work with different combos so my bike is set up using all SE stuff except for the Mikuni. I guess you're not going to go the same route as was done on my bike (I didn't build the engine myself. It was built by a legendary engine guy in Alaska and my hats are off to him.) So for a cam I'd call a cam maker like Woods or Andrews and see what they recommend for your paticular set up. I always think it's best to go with a proven head/cam combo from a proven tuner like Branch Flowmetrics or any of a bunch of other guys.
Both 4cams & milindh are offering some pretty good stuff here. But I'm thinking it's a little "over-kill" for what you seem to be concerned with at the moment.
What I highly recommend is that,regardless of which cam-maker you have in mind,you go to "andrewsproducts.com" and click on "pick a cam" just below "tech-questions" on the home page. There you'll find a relatively short,yet excellent explaination of camming,and your options,etc...
Then,go to their selection of EVO cams. Each cam will have a segment going across the page with it's spec.s...and to the far right of each there's a brief summary of that cams charactoristics...power(rpm)band...and,recommendat ions for what eng-size/comp-ratio,etc, it's best suited for.
All of which is,of course applicable to ANY cam-makers stuff...noting you'll probably be wanting/needing one that starts "coming-on" in the 1500-2000 rpm range...as opposed to the 3000 or MORE range...for what you described for YOUR wants/needs at this point in the "good-life"
__________________ "If at first you don't succeed, try again...then swear"
Mark Twain
EvoKenEvo is right on going to a site like the Andrews one. That kind of info can be invaluable in choosing a cam. The other other thing to consider when going to a bigger cam is the valve spring set up. As lift and duration go up you need a different valve spring length and compression strength setup. With a mild cam this is less important but, still, check with the cam maker about this. The same applies if you do some work on the heads.
My FRX4 starts coming on around 2500 rpm and really hits its stride at 3500 and pulls like a freight train all the way to my 6200 rpm limit. It doesn't like to putt around town at anything less than 2000. It's really lugging at that point and lower. No big deal in the lower gears but in fourth or fifth I rarely run it at less than 3000. I guess that, by Harley standards, my engine would be considered a higher revving and hotter engine than most but I like the big 3500-5000 rpm mid range and the strong top end. It fits my style of riding.
The bike has 30k on it now and it still takes a really strong 88 ci TC to even think about keeping up with it. Shortly after it was built it dyno'ed at 92 rwhp (or so I was told by the previous owner who seemed like a very upfront guy). It's starting to show symptoms of worn valve guides now, probably because of the high lift cam. I think next winter I'll do a top end job on it. For now I'm having a lot of fun riding the little beast.
might b abit late with my comments any ways i got a 97 evo ev46 cam adjustable push rods crane ignition module 42mm mikuni carb s&s slip ons k&n air filter gettn 75hp goes like the showers no problems with any thing had to raise jet needle one notch twin cams see ur later
I just spoke with an old friend who moved to Arizona years ago. He recently went with just about the same set-up you described (less the Mik-42 carb) and,seems to really like it. Neither he or his wife are what you'd call "light-weights" yet he claims that there's plenty of torgue down-low with the EV-46 that I would'nt have expected to hear,along with more RPM than the EV-27 he'd been running before over-hauling the engine's upper-end with all stock parts. Now,at 55-K miles,I seem to be needing new valve quide seals and feel I may be pushing it with the stock lifters still in my engine...figuring that as long as I'd have to pop the heads anyhow,might as well do the whole upper-end (possibley milling the heads .050"etc.) and cam stuff... as well as take a shot at R&R'ing the stock breather-valve with an S&S reed type breather. So,"anyways" would appreciate a 2'nd opinion on the low-end torque YOU'RE getting with that cam..noting I'm currently running a 65-T rear pulley (keeping right up with MOST of the TCs around here) and believe I could get away with going to a 61-T with the EV-27 in mine...and,I'm not even considering the EV-3 w/o the fast-ramps that the 27 & 46 have to open those doors and slam (?) them shut.
By the way, what kind of MPG are you averaging ??
__________________ "If at first you don't succeed, try again...then swear"
Mark Twain
Cam Change 
A "walk in the park" 
Linear Mode
