I recently upgraded by 2017 CVO Limited 114 to a Fuel Moto installed/tuned 128. Here's the thread for more details on the Build https://www.hdforums.com/forum/milwa...xperience.html

I started this thread since a few of you wanted to hear my impressions after I had some miles on it. Today I had a nice 200 mile ride. It's abit cool today (45F) so take that into consideration when I share the Engine Temp's I observed.

Start up and Idle - 1 day ago I found the bike difficult to get started but I think my battery might have been low. After getting a really good charge on the battery, the bike starts quite easily. Idle was set higher than most M8s at 1000rpms. The high lift Wood WM8-408 cam requires it since the RPMs "roll" abit during idle. Bike never stalled once but worth noting the idle is slightly higher than a normal bike.

Sound - If you're looking for an engine build and exhaust to frighten young children and scare old folks, this ISN'T it. This bike is remarkably quiet for the power it produces. Slightly louder than a stock bike. Perhaps abit louder than a Stage kit M8 with Street Cannons. Louder at open throttle but not obnoxious at all. Absolutely silent valvetrain. From the horn side of the engine, the valvetrain is nearly impossible to hear. The Jackpot Hi-Rollers have a nice deep sound and open up nicely with the throttle but nothing that would standout as being "loud". Fortunately I have my TC 110 with Fatcat to terrify animals, small children and actually a few grown men with its exhaust!

Clutch - The AIM SDR will take a little getting used to. It's definitely a harder pull than stock but very similar to my old clutch with Harley's heaviest clutch springs - 1275s. And of course it's a tighter pull at upper rpms but nothing outrageous. I definitely wouldn't want this hard of a clutch pull for parade duty but I think for normal riding its fine. We'll see over time if I feel any fatigue and need the "Light Force" Slave cylinder, but I don't think it'll be needed. There is absolutely no slippage. When the clutch is dropped, there is instant power available.

Heat - It was only 45 degrees outside so keep that in mind but I was still surprised how cool the engine ran. ETs were mostly in the 230's, some 240s and a high of 252. With my old Stage 4 M8 117, that engine almost never ran below 270 and even in cold temps could be much higher. Obviously the EPA-compliant Street Tuner tunes keep these M8s running lean resulting in the much higher engine temps with those "compliant" tunes. Coolant temps were pretty rock solid around 135 degrees.

Performance - Simply amazing. I'm not sure where to start because there was a smile from start to finish. The power with this much torque so low and hp that never seems to end makes riding a joy. Red line limiter is 6400rpms so bumping the rev limiter isn't very likely. Simply astonishing power whenever and wherever you need it. Shifting becomes a secondary thought because you can grab a handful of throttle from anywhere. If I wanted to rip it at 2500rpms, the bike jumped forward. On the highway, 6th gear, running 75-80 and want to pass NOW?? No problem, just rip the throttle. no need to downshift. The bike explodes forward and you're at triple digits in an instant. (Also worth knowing there is no speed limiter now. No clue what the top speed of this bike is now and I doubt I'll ever experience it!)

In the twisties, higher rpms are a blast. Downshift for a curve and at the apex, rip the throttle and the bike comes tearing out of the curve. No hiccups, blips, burbles or any hesitation whatsoever. The tune was absolutely perfect in every way you can measure a bike. And yet the bike has gentle manners at all speeds and rpms. Just want to poke along? No issue at all. In fact, if it weren't for the CVO 128 derby cover, it would be next to impossible for anyone looking at my bike to know the beast of an engine it has under the tank. Just the way I wanted it.

Fuel mileage - Yep, everything fun in life has a price to pay. In the case of this 128 and its power, the price is fuel economy. Granted I was having a "fun" day with this new throttle but the fuel economy was down around 29mpg measured on the PV. I figure normal riding might be around 32 over the long term and maybe 37 or so for long, cruise-control, highway miles. But anyone interested in this motor should know you will likely be the "shortest" tank in the group you ride with.

Small bit of advice - Please don't take offense if you took a different path with your own engine build, but I really don't "get" the whole small overlap so-called "torque" cams. Ok, I get it if you are trying to save money and are looking for a bolt-in cam, but for only about $500 more for hi-lift valve springs, you can have your cake and eat it too. This Wood 408 Cam delivers as good, if not better, low end torque (with the smaller headpipe and factory heads) then some of the best "Torque" cams PLUS you get all the HP that you would lose with the bolt-in torque cam.

If you're only installing a cam, then a "torque" cam makes good sense. But if you're going to the trouble to pull the heads, cylinders and pistons for a Big Bore upgrade, why leave so much performance on the table by installing a "Torque" cam? The only additional cost for most Big Bore upgrades would be the cost and install of hi-performance hi-lift valve springs to accomodate a higher lift performance cam. Most of the high lift cams require more compression but I'm not sure I see the downside going from 10.75:1 to 11:1 that's in my 128 build.

All in All - For the money, the fun factor in this build is terrific. The bike is very subtle...until its not! Your right hand decides if you just want the bike to be a neighborhood friendly touring bike OR a "let 'er rip" beast. The biggest downside is definitely going to be tires for 2 reasons. 1) rear tires will definitely wear out sooner 2) I won't want to run the tires down as far as I might have with less power.

In summary, this engine build is simply a blast to ride and definitely to be considered if you're contemplating a Big Bore M8 build.

 

Good write up. Based on my FM 124 experience I believe your gas mileage will increase each tankfull for about the first 1,000mi then level off at about 4mpg less than the stock bike. Mine averages about 38mpg after 9,000mi.

Even though they break it in on the dyno, it continues to breakin as evidenced by the mileage increase.

 

Thanks for this write up, this is what is lacking by most just posting up a Dyno sheet, the seat of pants riding experience!

Basically you told me what i wanted to hear, regarding the manners on the throttle etc, which goes with hdrider1 earlier feed back
as i am doing similar but on a Heritage ,already have the parts just waiting on the bike for home build this winter.

 

Great job on the write up, it's informative and detailed. What most of us are looking for. It's been nice reading some new threads, instead of the ones that have been beat to death. Thanks for the update on your new ride.

 

Great review with all the information given perfectly!!! I will continue to follow this and your thoughts as time goes bye!!!! I’m patiently waiting for my 128 build to be completed on my 19 CVO RG... Enjoy the bike my friend. Any thoughts or reviews on your other bike they did work on?? Just wondering your thoughts on that? Thanks, Scott

 

And this is with stock heads, correct?

 

My 2010 CVO is a blast to ride for a different reason. Its plenty powerful and in some respects "feels" more powerful than the 128 only because the exhaust makes the bike sound like a locomotive barreling by. 120hp/127ftlbs is a blast particular when it "assaults" everyone around you with the sound of a ripping TC and a D&D Fatcat. I've done a 6000 mile trip on my 2010 CVO 110 bike but if I had my choice for long distance riding, the 2017 CVO 128 will definitely be my preference for the future. If my objective is frightening grown men.... then my choice is definitely the 110, Wood 408 cams, Hillside headwork and the Fatcat 2:1!!

 

Yep. the 128 build was with stock heads. No changes other than upgraded Wood Performance Hi-lift BW-4V Springs https://www.fuelmotousa.com/i-238977...%7Cyear%3D2014 to handle the higher lift of the Wood WM8-408 cam. It was and is my view that if you aren't planning to go to a HIGHER performance exhaust header like the Jackpot XXX, then I don't think you'll get your money's worth out of upgrading to Performance Heads. The factory M8 heads are so good, the benefits of higher flowing heads will be minimized unless you are after BIG HP #s with a REALLY Hi Flowing exhaust. The downside could be slightly lower torque down low but with HP over 150 you're not likely to be spending much time at lower RPMs.

That's why I stayed with the factory heads to match the smaller FM 2/1/2 headpipe to get lower rpm Torque for 2 up riding but with plenty of ripping HP when riding solo.

 

How many of us here are saying “I wish FM was closer to me!” Lol. I do. Carry on.

 

after all you went through with your last M8 you deserves this one! may it bring you MANY miles of smiles!