Recently sold my 2021 ZForce 800 Trail and have a few spare parts and accessories left over:

CFMOTO factory OEM passenger side 3-point seat belt, part #5BY2-341200-10000. Includes complete belt and latch setup and is ready to install (no mounting hardware included). Fits 2020-2021 Zforce 500, 800 Trail and 800 EX models.

Removed from my ZForce after about a year when I installed 4-point harnesses. Used but in perfect working condition. Sells for $130+ new. Asking $20 shipped to contiguous United States (contact me for additional shipping options).

All digital payments accepted. Will ship the same day or next via USPS Ground Advantage. Tracking will be provided. All sales final.

Recently sold my 2021 ZForce 800 Trail and have a few spare parts and accessories left over:

Outerwears Pre-Filter, model #25-5900. Used but in like new condition. Was installed for a year on 3-4 weekend trips on the air intake tube as a pre-intake filter (between seats inside cabin). A must have for your CF-MOTO!

Sells for $20 new. Asking $10 shipped via USPS Ground Advantage to contiguous United States (contact me for additional shipping options).

All digital payments accepted. Will ship the same day via USPS Ground Advantage. Tracking will be provided. All sales final.

Recently sold my 2021 ZForce 800 Trail and have a few spare parts and accessories left over:

Uni Filter #UFM-400 Foam Filter Service Kit. Includes foam filter cleaner and oil in original box. Used 4-6 times (~ 75% full). Should work on any brand foam filter. A must have for your UNI filter upgrade!

Sells for $25 new. Asking $15 shipped to contiguous United States (contact me for additional shipping options).

All digital payments accepted. Will ship the same day or next via USPS Ground Advantage. Tracking will be provided. All sales final.

Recently sold my 2021 ZForce 800 Trail and have a few spare parts and accessories left over:

CFMOTO factory OEM 2-piece air filter, part #0800-112000-20010. Fits most  2013 – 2023 CForce, UForce and ZForce SXS and UTV models (does NOT fit any 950 or 1000 model or the UForce 600). Includes foam overwrap pre-filter and pleated paper filter.

Removed from my ZForce almost immediately after purchase. Not sure it was ever used on the trails. In excellent, like new condition. Sells for $50 new. Asking $25 shipped to contiguous United States (contact me for additional shipping options).

All digital payments accepted. Will ship the same day via USPS Ground Advantage. Tracking will be provided. All sales final.

Recently sold my 2021 ZForce 800 Trail and have a few spare parts and accessories left over:

RAM Mounts tablet holder setup to mount your navigation tablet in your CFMOTO. Used for about a year on 3-4 weekend trips. Mounted on the passenger side handle bar of my ZForce to hold my Samsung" 9.6" Galaxy Tab E (NOT INCLUDED). Fits larger tablets as well. Used but all items in perfect working.

Includes the following parts:
• RAM Tab-Tie tablet holder (#RAM-HOL-TAB25U).
https://rammount.com/products/ram-hol-tab25u
• RAM mounting plate with B/1" ball (#RAP-B-202U) in high strength black composite.
https://rammount.com/products/rap-b-202u
• Arkon 3.75" long shaft arm for 1" balls in high strength black composite.
• 1"-1.25" clamp for roll bars and handle bars in black aluminum.

Paid $75 for the whole setup. Asking $40 shipped to contiguous United States (contact me for additional shipping options).

All digital payments accepted. Will ship the same day via USPS Ground Advantage. Tracking will be provided. All sales final.

Recently sold my 2021 ZForce 800 Trail and have a few spare parts and accessories left over:

Set of 4 CFMOTO factory stock OEM coil springs. Used on my Zforce for about a year and 3-4 weekend trips before I replaced with Bandit Springs.

Used but in perfect working condition. Asking $45 shipped to contiguous United States (contact me for additional shipping options).

All digital payments accepted. Will ship the same day via UPS or USPS. Tracking will be provided. All sales final.

Did you try swapping back to stock tires and wheels and see how it does?

Yea that was something we tested. Issue was finally resolved - see: https://cfmoto-forum.com/800ex800/power-issues-on-800-trail/msg52158/#msg52158

[A few weeks ago, it FINALLY got solved!!!]

Ok, final update on this topic:

A few weeks ago, it FINALLY got solved!!! I ended up calling and then sending an email to CFMoto Customer Service pleading with them to do something...anything...to help the Dealership figure out the problem and get it resolved.

They listened. Within a matter of hours, someone from CFMOTO (some sort of engineer or high up service tech I'm guessing) had called the Dealership and told them exactly what the issue was. They had a few possible causes, but turns out it was the first and most likely culprit that they suggested.

They were familiar with the issue and suspected it was the air filter inlet pipe (https://cfmotousaparts.com/product/inlet-pipe-air-filter-cfmoto-oem-0800-1110b0-20000/). Specifically, the rubber boot elbow at the end of it. They said that section of hose was collapsing and cutting off air flow. But only under load and at top end power. So it wasn't something that could be replicated in the shop - or seen while test driving due to where it is located. 

I believe a new/upgrade version is available with some sort of reinforcement to prevent it from collapsing. It was mentioned that the foil type heat tape that I put around the intake between the seats to keep dust down and heat out (I have seen soooo many other owners doing this!), could have led to that piping getting hotter than expected and softening - thus leading to it being able to collapse inward.

Sooooo...after 5 months in the shop, $1,500+ in new parts and pulling out what little hair I have left (and the service manager at the Dealership doing the same)...turns out it was a $40 part that took just a few minutes to replace!!!

I was seriously beginning to question my confidence in these machines and this brand. But CFMOTO customer service has made me a fanboy again! Thanks NMKawierider for all of your suggestions and help along the way - keep up the good work!

Did I read it right, the machine appears to run properly in low range but presents with dramatic lack of power in high?

Yep. Thoughts?

Is there any longer video of the problem? 1-second just isn't much to go with. I am not sure what the top speed is in low range. It would be to the RPM limiter on ones prior to 2023 which is about 7750...and guessing around 30mph..ish. In low and in 4wd might have a lower limiter. Mine does not. The result of running a Chinese engine at the limiter for an extended period is anyone's guess..but I would suspect it would develop mechanical problems from the heating and oil breakdown.

No that's the only video he took. Just ran ~ 20 MPH and then suddenly stopped. This repeated over and over. Felt and sounded like you left off the gas BUT it was the engine cutting out - that's what you see in that video. He had it floored that whole video despite what it looks and sounds like. So it would go fast for several seconds like normal and then just hesitates for a second (power shuts off), repeat, repeat.

Acting more like a power issue. Really take a look at the airfilter...and do test it without that prefilter..really-I'm serious.

Just remembered something else to pick your brain about:

Before all of this started, my kid was driving and noticed some power/hesitation issue. Would go about 20 MPH and then hesitate (like the power was getting cut...governor sort of effect). Thought he was in High gear BUT turns out he was just in Low gear. At that time when he told me what it was doing, I just assumed that was normal - just the engine unable to go faster geared down so low.

BUT IF he gave it holy hell going as fast as he could in low gear for a while, what damage could that cause (if any)? More specifically, any way you think something like that could have led to the problem I have now? What is a normal top speed you could do in Low gear?

He took a video (hopefully it attached). That's not him letting off the gas at the end - it's the machine just loosing power and dying for a second.

Acting more like a power issue. Really take a look at the airfilter...and do test it without that prefilter..really-I'm serious.

Will do for sure! Once I hear back from them about how it did with stock tires on it again to test larger tire theory; I'm going to put the stock air filter back on and remove the prefilter and then do a test run.

Thanks as always and stay tuned... 

Also if you didn't re-cal the speedometer it will show much slower then it really is.

Tested and ruled out that theory last week when I test drove it. Used GPS app on my phone and it was within 1 MPH the whole time. So speedometer shouldn't been the issue.

Not to mention the first time I really noticed this issue was on the mountain highway roads (pavement) in West Virginia back in Oct. The inclines slowed me down so much could have literally walked faster. My group of other riders on ATVs and RZRs left me in the dust like a joke...it was insane how slow it was going...like 10-20 MPH was all it could do on those hills. I was speechless how under powered it was. Totally embarrassing lol.

Mine stock when new without anything else would do about 65 on the flat at 5200 feet. Adding the 27" tires alone took it down to 56(speedometer had to be re-calibrated) but re-clutching took it back up to about 59. Then I added wind shields. That dropped it to about 52. With that much added wind resistance the 800 just can't overcome it and get anywhere close to the RPM limiter. I can take the windshields off and it get pretty close...but still not hit it. Keeping in mine that for every 1000 feet in elevation off seal level you loose about 3% power. For me here at the house that's a little over 15%. That means my little 60HP engine is putting out less then 51HP. You can imagine the loss when I get where I ride mostly...above 8500 feet. So..yeah depending on your elevation those 28s with no clutch mods will have a dramatic effect on speed on any engine. Also, if you are running the Unifilter or any other foam filter, make sure it's not over-oiled as it will restrict the air flow...and if you are running a prefilter such as an outerwears, take it off and try it. They are restrictive even clean above 4K.

I do have the Unifilter as well as the Outerwears pre-filter. Once I hear back from them about how it did with stock tires on it again, I will make sure the Uni is a bit dry and remove the prefilter and do a test run.

I get that the tires would make a difference...but a 25-30 MPH difference?!? I'm going to feel like a totally idiot if that's all this issue was the whole time!!!

My thoughts? After what they have already done(or not done) I find it difficult to believe anything they say. That's just me. Have them give you the print-out of the actual numbers on fuel pressure and flow rate, compression, valve lash and running system (not just battery) voltage. Then post them. I do believe them on the re-assembly of the clutch because it's happened before to others.. and now the splines are likely damaged which means the cam plate and possibly the shaft will need replaced. Maybe not...hope not but if so it's on them. Sorry if it sounds like I have attitude but I'm so tired of people being taken to the cleaners because of outfits like these guys. I might be dead wrong about this dealer and if so I am sorry. It's just I hear about so many getting the "short end of the stick" every day and over time it gets to you. Even me...I just got the shaft "again" from my Ford dealer. 5K to replace a 1900-dollar turbo that only had 3800 miles on it...and the impeller-to-housing noise is still there...bs I say. Make them prove it by giving you the actual data. OK, rant over.. Carry-on 

Latest update from last week:

• Again, all the tests you mentioned (fuel pressure, voltage, compression, etc) checked out fine - so they say. I am going to request actual numbers like you mentioned though and will post when I get them.
• New drive belt and rollers on = no difference.
• New drive shaft, clutch housing, clutch assembly, gaskets, etc parts all finally came in stock and have been installed = no difference.
• The rattle noise that popped up after they installed new belt/rollers a few weeks ago did go away with these new parts... so either something with these old parts OR they figured out how to reassemble correctly this time. That's one positive thing so far!

So 3 months and $1500 later, the problem is the same! I test drove it in their parking lot again last week and same result. Simply will not go above 35-40 MPH in high gear (flat road, pedal to the metal, just me the driver with little to no gear on board).

I starting to feel like I'm going crazy now...these things DO go faster right?! Surely would have noticed this when it was new. I swear I remember getting it up to 50-60 MPH previously. How fast do they usually go??

The only other thing I can think of is the new tires. I upgraded them to 28" ITP Blackwater Evolution Mud Terrains last year. I'm sure this effects gearing/top speed/weight/etc...but SURELY not that much! Right?! What kind of difference in power/top speed would be normal with slightly larger tires? I asked them to temp install some stock wheels/tires from another 2021 they have in the shop to test this theory this week.

What else could it be?!?