CFMOTO 800MT Engine Deep Teardown - "Caramelized" Crankshaft Revealed!

Added: 2026-05-11

[00:00:00]An engine sabotaged with sugar.

[00:00:04]In this episode, we're tearing down a CFMOTO 800MT engine.

[00:00:08]We'll start with the bottom end this time.

[00:00:12]Because someone added something to this engine.

[00:00:15]I suspect it might be salt.

[00:00:18]Let me have a taste.

[00:00:21]Is it sugar or salt?

[00:00:32]Oh my god.

[00:00:35]Taking this apart is a good chance to verify something.

[00:00:39]Whether the 800MT CFMOTO gave me last time......was a "special press version."

[00:00:45]Alright, I see sugar in here too.

[00:00:49]Since some people raised doubts, I'll use real action to dispel those doubts.

[00:00:57]The slipper clutch is just like the one I tore down before; it has the same hard-anodized finish.

[00:01:04]The inner hub shows no wear.

[00:01:07]It’s reusable. This is our first survivor!

[00:01:12]Let’s check the clutch plates.

[00:01:14]The plates look okay visually, but they are bone dry.

[00:01:20]There’s no oil on them at all.

[00:01:23]Take a look, everyone.

[00:01:26]The entire inner clutch hub assembly is still usable.

[00:01:31]Now let's look at the clutch basket.

[00:01:33]The basket is also fine and reusable.

[00:01:37]It’s exactly the same as the 800MT I stripped last time.

[00:01:42]It’s the dual-compound type, with the hard-anodized process.

[00:01:46]The owner said this bike only has 10,000 km on it.

[00:01:51]After the sugar was added, it ran for 20 km.

[00:01:55]The sound became very strange, and there was a severe loss of power.

[00:02:01]When he went to the shop and opened the oil filter, it was covered in sugar.

[00:02:09]That’s how the owner determined it was sabotaged.

[00:02:13]The cylinder head cover is off; it looks brand new inside.

[00:02:18]After all, it’s only a 10,000 km engine.

[00:02:21]As you know, sugar doesn't dissolve in engine oil.

[00:02:26]So when sugar is added to an engine, it only melts once things get hot.

[00:02:33]That’s when it can pass through the filter and enter the oil passages.

[00:02:38]Look at this camshaft cap; it’s already showing signs of wear.

[00:02:46]But it’s not too severe yet.

[00:02:49]Let’s check the camshaft.

[00:02:52]Yes, it’s the alloy steel camshaft.

[00:02:56]Exactly the same as my previous teardown video.

[00:03:00]The lobes have some wear, but it’s not as catastrophic as I expected.

[00:03:07]Check the intake cam.

[00:03:11]Also some slight......wear.

[00:03:15]It’s not as bad as you might imagine, right?

[00:03:19]The rocker arms show no wear either.

[00:03:23]This "sugar trick" is truly wicked.

[00:03:26]It’s designed to make you break down mid-journey.

[00:03:30]Because sugar takes time to melt.

[00:03:34]It melts slowly as the oil heats up, and then......gradually enters the oil system.

[00:03:44]Hey, the starter motor still works!

[00:03:47]But looking at the camshafts and the state of the head, it means the sugar-tainted oil definitely reached here.

[00:03:59]No sugar was found inside the stator cover.

[00:04:03]The design of this engine actually has an advantage: Two coarse filters and one fine filter.

[00:04:11]Plus, it basically has a dry-sump-style design.

[00:04:15]It has a separate oil storage area, which helped isolate the sugar in the pan.

[00:04:23]Wait, I found some bronze shavings here.

[00:04:26]These two design features acted as a barrier against the sugar in the overall oil circulation.

[00:04:33]In a conventional wet sump, it would have been much worse.

[00:04:36]The main bearings look fine.

[00:04:40]Balance shaft bearings are also okay.

[00:04:44]No issues there.

[00:04:48]More bronze shavings found here.

[00:04:51]Let's check the bearings.

[00:04:54]They're SKF.

[00:04:55]Consistent with the previous teardown.

[00:04:59]This one uses NSK from Japan.

[00:05:02]The last one used NTN from Japan.

[00:05:05]No real difference there.

[00:05:07]Check the balancer shaft.

[00:05:10]No problems.

[00:05:12]No scoring.

[00:05:14]Look, this connecting rod is seized.

[00:05:17]I guess this is a case of "sacrificing the tail to save the body."

[00:05:23]It’s lucky it seized early.

[00:05:26]Otherwise, if more melted sugar had reached the oil passages, the consequences would be unthinkable.

[00:05:34]The rod on this side was also on its way to seizing.

[00:05:39]But it didn't fail completely.

[00:05:42]Check the bearing shells.

[00:05:43]Daido Japan—no issues there.

[00:05:46]Matches the previous teardown video.

[00:05:50]Now look at the severe one.

[00:05:53]The bearing shell is fused to the crankshaft.

[00:05:55]Look at this rod... It’s toast.

[00:06:00]Look at the crank.

[00:06:02]It's become a "caramelized crankshaft."

[00:06:06]I've had caramelized sunflower seeds before, but should I give this caramelized crank a lick for you guys?

[00:06:14]This bearing shell is in terrible shape.

[00:06:18]It literally welded itself to the crank in the middle.

[00:06:22]I couldn't pry it off no matter what.

[00:06:25]Let me zoom in for a closer look.

[00:06:29]The sugar really did its job.

[00:06:33]It just won't budge.

[00:06:37]It reminds me of friction welding.

[00:06:41]This must be the result.

[00:06:44]Don't ever do this to someone, guys.

[00:06:47]As for the owner, he’s already replaced it with a new engine.

[00:06:52]Total cost was nearly 30,000 RMB.

[00:06:56]And he won the lawsuit.

[00:06:59]You can imagine the legal consequences for the culprit.

[00:07:02]The owner donated this engine for a teardown......just to share the knowledge.

[00:07:09]Let's see if we can extract any more value from it.

[00:07:14]Just a reminder of how serious this is.

[00:07:18]30,000 RMB in property damage— think about that.

[00:07:23]And this could even escalate to a personal safety issue.

[00:07:27]I can't get the bearing off, so let's leave it at that.

[00:07:32]The crank is an alloy steel forged unit.

[00:07:35]No doubt about that.

[00:07:37]Same as the previous teardown.

[00:07:40]In a way, it's good the crank failed early.

[00:07:44]Otherwise, the damage would have spread further.

[00:07:48]Check the piston.

[00:07:50]The piston is still usable.

[00:07:52]There are some marks, but nothing that prevents use.

[00:07:57]Here is the "caramelized" crank and rod.

[00:08:00]Now let's check the right cylinder piston.

[00:08:04]Also usable, no problem.

[00:08:08]The connecting rods are the cracked-cap type.

[00:08:12]This is also fine.

[00:08:15]This is an early-batch 800MT.

[00:08:18]The pistons are identical to the KTM 790.

[00:08:23]The newer ones have different pistons, but they are also forged.

[00:08:27]So no downgrades there.

[00:08:30]The timing chain is a DID.

[00:08:34]Matches up. Now look at the cylinder block.

[00:08:39]Lucky it’s a Nikasil-plated cylinder.

[00:08:42]It’s starting to show marks, but no actual damage.

[00:08:47]Alright, teardown complete.

[00:08:49]Thanks for watching.

[00:08:51]And seriously, don't do anything illegal.