Hi all,
Ride a 2017 Road King Special w/ a 107 M8. Bike has 9100 miles on it. I purchased it pre-owned (less than 2000 miles on the bike). Previous owner installed a Centrifugal clutch on it that HD took off and replaced with a stock clutch assembly. Went on a 190 mile ride earlier in the day, no issues. Took the bike out later in the evening to attend a wedding. On my way home I was admittedly getting after it going 90-110 (or whatever the speed limiter is) for about 25 miles. I noticed that when I shifted into 6th, the bike would rev, but didn't really feel like it was going any faster around 90mph. I would lower the revs, and it felt like it would "catch" and I would push above the 100 mph mark, but the more I twisted the throttle, the same issue occurred. I have had my bike this fast in the past and have never noticed this issue. No issues shifting. Bike goes into gear fine. I have a 107 w/ FuelMoto 2 into 1 and recently installed a Zipper's 468 cam w/ S&S oil pump. I am making around 110hp and 115 torque via the dyno. I have around 500 miles on the bike since the cam install. When getting off the highway, I noticed that ALL gears had the same issue. Bike would rev out, torque was lacking.
All fluids changed 500 miles ago w/ AmsOil oil/tranny/ primary fluid, all fluids are at correct level.
Thanks for your input.
PS- I have no plans of taking my bike past Stage 2.

 

No idea what bike, year, etc you have. I know the softails have a clutch cable, wondering if it's too tight?

You mention the mods, so I assume you have it tuned with aftermarket tuner, but you didn't list that either. I mention this about the top speed limiter (going into 6th) and hitting the 111 mph. Are you feeling that?

All that aside, if you are truly making the clutch slip, you should be able to do that on hard pulls well below the 100 mph mark. The engine will rev, you will feel it "catch" on the pull. You say you started to notice it in lower gears after that. If this is indeed the case, I would first ditch the Amsoil in the primary. Fuel Moto had me go to conventional (I use BelRay) when I went to the 128.

Did you verify the primary oil level? Is it too high maybe?

 

Sorry on the vague details.
2017 Road King Special; Yes, I have an aftermarket tuner. I would get around 100mph, the bike would rev, but wouldn't go any faster. Let off the throttle, revs would go down, and you could feel it "catch" and pull strong to the speed limiter (around 110mph). Getting off the highway, and launching from the red light, the bike would rev, but again, it didn't seem to be putting down the torque that it normally does (high RPM, lower torque than usual). Primary fluid level is correct and easily shifts gears/into neutral.

 

You better try the conventional primary fluid then. You can also go to the HD heavy clutch springs, and the AIM SDR clutch.
I have all 3 things in my primary

 

Change your primary fluid. I'd try the H-D Formula Plus & keep the level slightly low. If you haven't glazed the clutch pack, this should fix it. Stronger clutch spring (diaphram) or new clutch pack may also be required?

 

I would say slipping all that was stated above is correct.

 

New clutch pack is fairly inexpensive, around $200 oem. New coil clutch springs are about $10 each. All are extremely easy to replace. I replaced my original stock clutch pack, but not the springs, at around 32k miles, because I am very tough on a clutch. No I don't abuse anything, but I make a point of a very smooth ride because I have a 75 y/o passenger most of the time. I sacrifice the clutch for a smooth transition gear-to-gear, and takeoffs.

Now, I am a suspicious type, especially when it comes to dealer shops. If a bike came to me with a note that a centrifugal clutch had been replaced in the shop and returned to "stock" condition, I would not assume that a brand new clutch unit had been used. In fact, I would assume that a well used clutch device was installed. Point being OP maybe doesn't know how many miles are really on that clutch, or what abuse it was subjected to before he got it. I think of a clutch the same as brakes. They will wear out.