2021 UTV 400 going downhill something releases to "Neutral" loud Clacking noise.

[Robert B]

Going down a 20 deg hill engine is holding UTV back. Then something releases like going into Neutral and makes a loud clacking noise. Have to use brake to slow UTV down. Then once level it shifts back into gear. Have done shift extension does not pop out of gear.

[Rainman]

On 9/16/2023 at 4:34 PM, Robert B said:

Going down a 20 deg hill engine is holding UTV back. Then something releases like going into Neutral and makes a loud clacking noise. Have to use brake to slow UTV down. Then once level it shifts back into gear. Have done shift extension does not pop out of gear.

Strange ... I had a similar problem. My UTV always seemed to hold back going down hill except one time it started to run away on me and I had to apply the brakes. The only difference was, no clanking noise. I didn't notice if it seemed to slipped out of gear by checking the dash lights, but then again, I was distracted by the speed and slowing it down. I will pay more attention and update if this happens again.

[Greg Kilgore]

Possibly the one-way bearing is slipping or warn.

That is what hold the machine back.

[Robert B]

10 hours ago, Greg Kilgore said:

Possibly the one-way bearing is slipping or warn.

That is what hold the machine back.

Thanks that is what I was thinking. It is intermittent so maybe over the Winter I will look into replacing it.

 

[Rainman]

11 hours ago, Greg Kilgore said:

Possibly the one-way bearing is slipping or warn.

That is what hold the machine back.

Yikes ... I have to get out there again and try mine out. I have less than 11 hours and 30 miles on mine and hope that's not my problem. I wouldn't even know where to start to replace that bearing.

Rob, keep us updated.

[Robert B]

Update on slippage in transmission. Don't use synthetic or semi-synthetic motor oil. Thought I was doing a good thing by using UTV/ATV semi-synthetic oil. Owners manual states if you use high quality oil it might cause clutch slippage. Changed motor oil and used Dollar General conventional motor oil 10W-30 and raised idle speed to around 1700 RPM. Most of the issue is gone, will change oil again after I put some hours on the current oil.

[Greg Kilgore]

Regular car oil doesn't have the stuff needed to keep wet clutch lubed like it needs 

Just make sure the oil rated "JASO MA" or "MA2".

Synthetic or conventional is up to you.

I read somewhere that the "MA2" rating is for engine exhaust with a cat and O2 sensor.

And I think the synthetic lets the clutch slip more than conventional. If there is a lot of miles on the clutch with conventional oil. Then switched to synthetic. The clutch is more likely to slip.

 

[aefron88]

This is correct JASO MA oil is a requirement for wet clutches, other motor oils are "Energy Conserving II" and will cause wet clutch slippage, and rapid wear.

The manuals I've seen out of Hisun/Coleman are not explicit or don't mention it at all.

[Greg Kilgore]

From Coleman 400 manual.

 

From Hisun 500 manual.

 

Also found out why some oils "meet" the JASO MA or JASO MA2 requirements and some are "certified" .

To get "certified" and be able to use the JASO MA symbol. Oil makers send oil to labs to get tested and pay big bucks so the can use the symbol that states their oil is "certified"

If their oil "meets or exceeds" then oil makers have their in-house engineers look up the specs and match it. No outside labs confirms it.

[Rainman]

On 10/6/2023 at 11:44 PM, Greg Kilgore said:

And I think the synthetic lets the clutch slip more than conventional. If there is a lot of miles on the clutch with conventional oil. Then switched to synthetic. The clutch is more likely to slip.

Not sure I understand your statement as to slippage. That is, which type oil is best, as to which conventional or synthetic may cause slippage.

I'm doing my first oil change and want to make sure I get the correct type. Coleman and Massimo both have available the JASO MA oil 10W40, but both of which are synthetic. Is that what I need to use?

[Greg Kilgore]

Use conventional NOT synthetic.

Synthetic will cause the clutch to slip and not grab especially if it's a high mile machine.

[aefron88]

Synthetic vs conventional has nothing to do with clutch slippage. The clutch slip is caused by viscosity modifiers used in "Energy Conserving" oils (you'll see that with the API Starburst ratings).

JASO MA rated oils are designed to work properly with wet clutches used in Japanese bikes, as well as ATV/UTVs etc that use wet clutches.

Do not use a non JASO-MA rated oil unless you can confirm it is wet clutch safe, and afaik the only common non MA rated oil that is ok is Rotella.

[Rainman]

11 hours ago, aefron88 said:

Synthetic vs conventional has nothing to do with clutch slippage. The clutch slip is caused by viscosity modifiers used in "Energy Conserving" oils (you'll see that with the API Starburst ratings).

JASO MA rated oils are designed to work properly with wet clutches used in Japanese bikes, as well as ATV/UTVs etc that use wet clutches.

Do not use a non JASO-MA rated oil unless you can confirm it is wet clutch safe, and afaik the only common non MA rated oil that is ok is Rotella.

Yes, and that was my confusion. The manual, from what I've seen, only states JASO-MA, but doesn't mention whether the oil should be synthetic or not.

I contacted a few guys who made videos on the Coleman UT400 and one stated he uses "regular motorcycle oil". Another just said he uses only "regular oil" because he also heard synthetic can cause slippage, but didn't mention if that regular oil he uses was JASO-MA or not.

The third guy I spoke to, who owns a repair shop stated the following: "As far as clutch slippage , you don't have to worry about that from the oil, being that these units come with CVT, no oil ever touches the clutch. And I don't see any reason full synthetic would harm this engine in any way. However that being said I do know that full synthetic oil in older Harley Davidsons have caused cams to spin inside the bearings creating a flat spot in the bearing. I do not see that happening to these units."

So with that said, I'm guessing that as long as it is a JASO-MA rated oil, it doesn't matter?

[aefron88]

That's correct on the MA oil.

Some of the info in that post is wrong.

There are two things moving the power from the engine to the drivetrain: first there's a wet centrifugal clutch, from that drives the primary cvt pulley, which has a belt to the secondary. The friction material on the clutch is prone to slipping with use of additives "energy Conserving II" API rated oils, which are used in most car oils. Cars use a dry transmission, most motorcycles use a wet clutch where the clutch plates are bathed in oil. The MA rated oils don't have that additive which causes wet clutch slip issues.

See attached picture of the friction disc of the wet clutch. Yellow stuff is the friction material. Once it starts slipping you get rapid wear, and also a lot of crud in your oil.

Generally speaking conventional vs synthetic, synthetic oils have more uniform molecules and hence lubricate better and resist more wear and tear before going out of spec. They also typically have better additive packages, because the manufacturer expects them to be used for more mileage.

Conv vs synth it makes little difference, and I would lean towards changing oil early on these machines being a large single cylinder ("thumper") they get more wear and tear than a normal car engine, and also I've read a fair number of timing chain stretching issues, which is typically an issue with accelerated wear of the pins holding the chain.