Engine/gearbox vibration

Hi there,

I bought this WR250R from 2008 and every few seconds or so it sends huge amount of vibration into the motorcycle. I think it's coming from the rear wheel or the chain but I'm not sure. Even when I press the clutch the vibration is there. I don't have any clue about what could cause this nasty vibration, it's like the whole motorcycle is breaking down.
I took the chain off, started the bike, put it in gear. When I look at the front sprocket here is a pulsating/intermitted vibration coming from the engine/gearbox I suppose. It is mild in 1st/2nd gear but gets violent in 4th/5th/6th. On the road it sends a huge kick in the wheels that after a day riding I can still feel my body shaking. There is no vibration at idle (gearbox in neutral).

Any ideas?

I am new to the WR but not to motorcycles. the first thing I would suspect is the crank balancer. a quick look at the parts book shows it is gear driven, which is usually a pretty trouble free design, but you never know. also, looking at the parts, I see a "drive gear" (#9 below) that has springs in the gear to cushion dynamic changes. I think it drives the waterpump. things like that can cause problems when the springs wear out or in some cases, fall out.

Is there any metal in the oil and/or the filter? check that carefully

WR250:

https://www.revzilla.com/oem/yamaha/2020-yamaha-wr250r/crankshaft-piston?submodel=wr250r-wr25rl

vindictive666 wrote:

I took the chain off, started the bike, put it in gear. When I look at the front sprocket here is a pulsating/intermitted vibration coming from the engine/gearbox I suppose. It is mild in 1st/2nd gear but gets violent in 4th/5th/6th. On the road it sends a huge kick in the wheels that after a day riding I can still feel my body shaking. There is no vibration at idle (gearbox in neutral).

I posted an answer in ADVRider, but ignore it, this is a far better forum.

Do the vibrations exist when bike is stationary, chain is removed, in neutral gear, motor is revving?

Nope, it vibrates only when in gear (check my initial post). Engine runs nice, no weird sounds apart from the initial rattle on engine start due to the tensioner but nothing to worry about (it lasts just 1 or 2 seconds until the pressure builds up). No metal in the oil either. I'm going to change the oil these days so I'm going to check again and I'll also be posting a video hopefully.

On the road, it's more pronounced at speeds above 50 km/h.

dogmeat wrote:

I am new to the WR but not to motorcycles. the first thing I would suspect is the crank balancer. a quick look at the parts book shows it is gear driven, which is usually a pretty trouble free design, but you never know. also, looking at the parts, I see a "drive gear" (#9 below) that has springs in the gear to cushion dynamic changes. I think it drives the waterpump. things like that can cause problems when the springs wear out or in some cases, fall out.

Is there any metal in the oil and/or the filter? check that carefully

Thanks for the reply, that means I need to tear off the whole engine to check these.

vindictive666 wrote:

Nope, it vibrates only when in gear

Then you have the answer: something to do with the transmission.

Before you open the engine though, check the sprocket: it may have eaten the drive axle splines.

I agree. if the engine sounds fine, the tranny/drive train is the problem.

I also agree that the sprocket & shaft are first in line for close inspection. you said that the vib is there even with the chain off and the pulse is coming from the tranny. that bodes not well for an easy fix, but double check the splines & cog first

can you hear any you noises when you turn the countershaft by hand in neutral? (engine off)

have you checked the oil & filter for metal?

Check this video I made today with the bike standing and changing gears. Let me know your thoughts.
https://photos.app.goo.gl/6hE4WF13T9HwZA666

It looks like a non-repeatable resonance, but where this is coming from is impossible to say.

Did you check the drive axle splines?

They're fine. I'll do another one today.

Check these videos too. https://photos.app.goo.gl/W69f7Uy9MPRp2Wzs8

First one is with the bike in 1st gear, second in 5th. You can hear an abnormal rattle in higher gears. And last, check the last video with the bike changing gears and pressing the clutch. It seems like the countershaft is misaligned. Sorry for the video quality.

that looks and sounds to me like it's time to split the case and see whats going on. it sounds like a bad bearing (at least) but I would guess it's more than that. it won't cure itself, and running it more only risks the possibility of greater damage. is there metal in the oil and/or filter? my guess is you will find bits of steel

Can't tell a thing; truth be told, even if I had the bike in front of me I wouldn't be able to tell what's wrong, and any shop you take the bike to will tell you the same thing.

Highly unlikely that the axle is misaligned or bent: that would result in a repeatable resonance, plus it would damage the oil seal so you would get a lot of oil dripping.

If the axle splines are fine, then open the clutch case and see if there is any damage there.

I put a magnetic oil cap and when I change the oil this week I'll let you know. But have you heard about this issue from other wrr users? Or I'm the unlucky one?

I can't quite follow the logic here: what kind of actionable information about this issue are you getting from changing the oil?

No, I don't remember ever seeing this issue on any bike, let alone the WRR. I'm still not 100% certain it's the transmission and not the engine.

johnkol wrote:

I can't quite follow the logic here: what kind of actionable information about this issue are you getting from changing the oil?

Someone said in an earlier reply to check for metal in the oil/filter. Of course it won't change the issue.

one reason to check the oil for metal is to get it out of there if contaminated. the other reason is that sometimes what comes out can tell you where the problem is. the DR650 has 2nd and 3rd gear blow up problems, and some cases there is vibes similar to what you describe.
the 3rd gear problem can shear the drive dogs.... if you get one in the oil you might have an idea. there is also something with the neutral too... a screw comes loose and falls out (inside the engine). I was into KLRs for a couple decades and ran tech days... found many a broken balancer (doohicky). sometimes with broken parts in the oil. also found missing shims, and thrust washers etc. and not just KLRs. there are other failure modes in certain engines that lead to significant quantities of aluminum shavings. also, I have over 40 years as an aircraft mechanic. oil spectrum analysis (SOAP) is pretty common. especially on turbines.

and yes, it won't change anything but it might give a clue if you find something