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2014 YZ250 Bad Grinding Noise When in Neutral

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Drain and refill with exactly 750ml of oil then tip the bike on the right hand side for a minute.

 

What I'm getting at is the kickstart idler gear has been known to squeal when the oil level is low...and the oil level check bolt can be misleading.

 

That's a quick and cheap test to start with.

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^^^ Exactly. :prof:  :worthy: 

 

Also, measure how much oil you drained out. Don't be surprised if it is much less than 750ccs.

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Thanks guys, I will try that when I get more oil. I have changed the oil twice in those 25hrs and both times I used the manual spec with the level bolt bs. There was probably less than a pint in the drain pan both times and I thought that was odd.  I will for sure measure it from now on. 

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👍

 

The Oil Check bolt has been in the wrong location for years, and has been the cause of much heartburn.

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If you are just trail riding or offroad racing it, use the whole quart of oil. Maxima MTL 80wt is great stuff.

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The crank nut on the right side of the crank is known to back off and rub against the case.  I would highly suggest pulling the right side engine cover off for inspection.

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OK, I put 750ml of oil in, layed it down on its right side.  Started it back up and still no change. Now I noticed just revving it in neutral it tries to lunge forward. As soon as I click it into gear it stops and everything works correctly.  See video.  :(

 

https://youtu.be/1_hpCwd9KMQ

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The lunging while in neutral, and scary noise are the same symptoms our bikes had when the oil level was low for too long.

 

One bike was cured by getting the correct amount of oil in the gearbox. The other required having the transmission bearings replaced.

 

Not what you wanted to hear, I'm sure.

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Some of the transmission gears freewheel on the shafts...if a gear bushing goes south on the shaft, it will squeal and lunge. Typically caused by low oil.

Once you put it in gear, the gear and shaft are locked together...so no more spin, no more lunge, no more noise.

Thats what it seems like from the symptoms. Your shaft may still be salvageable...so I wouldnt keep running it.

So now you get the "opportunity" to install the WR tranny and freshen up your top end while youre in there! It will be like a whole different monster.

A motor rebuild seems intimidating but these things are crazy simple and beautifully designed to be rebuildable. Most all of us have had to do a rebuild for one thing or another. Typical bill is a few hundred bucks if you do it yourself.

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Thanks guys for the replys.  I removed the engine today.  I have a buddy who is a bike mechanic and I'm going to help him tear it down next weekend.  WR trans? Sounds good already, I'll have to do a search on it and find out more.

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I have a 2015 with 25 hrs as well it's doing the same exact thing and same noises.I changed out the oil and replaced with new oil and the same thing is happening. Please let me know the out come is Thanks. 

Edited by mikenash

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Check the bearing on the stopper lever assembly to see if bearing is still there. My 08 lasted a long time before coming apart. The replacement only went a few months. Had to tear down to get all the lose parts out as well as change a few gears. It was causing the tumbler to stick gave the bike false neutrals.

 

This is the same part number as my 2015. I read in MXA test of the 250X there is an improved stopper lever assembly. Maybe this is the part we need to upgrade to.

 

Any Ideas?

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I looked up both stoppers and the 2016 YZ250 and YZ250X and they are different from 2015 and before. No more bearing, it's a wheel supported on both sides. If it fits older bikes I am going to put it on both 250's. Such a tiny little parts can cause so much grief and damage. Waiting to see what the OP found.

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Man, I can and can't believe that I'm not the only one having this problem.  Here I was changing my oil to prevent wear and damage and now my brand new dirt bike is f'd up.  This is crazy that Yamaha would do something like this.  I've NEVER had any sort of failure on my YZF's and all the Yamaha's that I grew up riding. I'll keep everyone posted.  Should be tearing the motor apart this weekend.  I'm really looking into the WR gearset at this same time...

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I looked up both stoppers and the 2016 YZ250 and YZ250X and they are different from 2015 and before. No more bearing, it's a wheel supported on both sides. If it fits older bikes I am going to put it on both 250's. Such a tiny little parts can cause so much grief and damage. Waiting to see what the OP found.

Is this the part you are talking about?

 

Stopper Lever Assy

BF1-18140-00-00

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Is this the part you are talking about?

 

Stopper Lever Assy

BF1-18140-00-00

 

Yes, But it looks like there is a different case number so it may not fit. For $30 I may just order one and see.

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👍

The Oil Check bolt has been in the wrong location for years, and has been the cause of much heartburn.

So , how do you check oil level between oil changes?

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My best guess is that the Oil Check screw is to be used while the bike is leaning on a triangle stand, and if oil oozes from behind the screw when it is loosened, then there is enough oil in the gearbox. It's only when no oil is evident should you suspect something is wrong.

If your bike is level (on a box stand), and no oil shows, that is a very Not Good sign.

 

I think the manual says to change gearbox oil every 2- 4 races or something like that. If you lost enough oil to cause damage within that timeframe chances are it would be pretty evident -- oil spots on the bikestand, truck bed or trailer floor, and the underside of the bike would probably be a mess.

 

The best recommendation I know is from the many riders that change their oil regularly, add the measured correct amount, and ignore the Oil Check screw. They don't ever seem to have any Low Oil issues.

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