01 WR250 engine noise

[Lunendan]

Greetings Gentlemen.  And Ladies ?  I am new here and a new owner of an 01wr250f.  I bought it after riding a friends 02yz250f, and loving the power, handling, and feel.  I have owned a cr250 2-stroke most of my life.  The wr seemed a good choice to ride the woods and pits, and I can ride it to work and leave my F-350 parked. 

 

So I bought the bike in Nh and registered it in Ma.  It seems to be all stock and unmolested and in great shape.  The guy explained to me how to start it, and it starts first kick, every time, even hot.  When  I test rode it, I noticed some intermittent engine noise and vibration, but it wasn't too noticeable and I attributed it to having the stock baffle in place and being all corked up with backpressure.  So I bought it anyways, got a light kit, and now have it on the road.  First day I rode it all stock in the pit to get a feel.  Then I removed the baffle and rode offroad again.  Large difference in power and noise as you know.  Still has the engine noise but is much less noticable.  When I ride on the road, the noise is much more noticable.   Street riding is no more than 50 mph and mostly back roads, no highway.  Yesterday I rode it to work, with the stock  baffle in to be quiet in the morning.  The engine noise was very noticable and making me nervous.  At work I removed the baffle, removed the valve cover, moved the exhaust cam as free mod.  Timing chain was tight and in good shape.  I did not have a feeler gauge that fits valves yet, so no measurement.  Reassembled and did the gray wire mod.  I rode the bike home and good grief, what a difference 3 free mods make.  The bike is so fun.  I also ripped through some trails and the pits on the way home.  Love the bike.  But on the road, at constant 4th and 5th gear speeds, at mid throttle, probably 30-40% rpms, there is an awful engine noise that seems to resonate and sounds like a clatter.  It does not really do it upon acceleration, but running constant speed or decelerating.  It sounds like this thing is going to come apart. 

 

I found multiple cases where the flywheel comes apart at the rivets.  So I was excited to inspect and hoped that was the problem. Easy fix.   I took the bike apart today and flywheel is fine.  Stator looks good.  No metal in the cased and I changed oil last week and it was clean.  I took the clutch side cover off too and everything looks good.   I rode in the yard at work and has no noise on hard acceleration and deceleration, and the thing rips pretty damn good.  It pulls the front wheel up well for a 250 fourstroker.  I am wondering if anyone has some insight for me.  I will have to get the proper feeler gauges and check the valves next.  What does it sound like when your valves are out of spec? 

 

I really like the bike.  My next step is to do the ground float mod and install a good battery to run my light kit.  Then I would like to get a q4 exhaust system and I will be happy for a long while.  But I am so nervous about this noise.   Is this a common thing that I am experiencing and can remedy? 

 

Thanks in advance for any help.  -Dan

[YZEtc]

I own a 2002 WR-250F, the nearly identical twin to your 2001 model.

 

If the guy you bought the bike from did not hand it over to you, BUY THE ORIGINAL OWNER'S SERVICE MANUAL.

This can be ordered at your local Yamaha motorcycle dealer.

This tells you how to care for the bike.

To me, no manual = big mistake.

 

I'm assuming you have changed the engine oil by now.

Correct?

The oil changing procedure is a bit different because it is a dry sump oiling system.

Even checking the oil level is a bit different.

 

Get the narrow feeler gauges and check the valve clearances just to rule that out.

Your local Yamaha motorcycle dealer can order them through their special tool supplier (K&L).

If they are too tight, well, you know you need to correct that.

 

However, if the bike starts easily when hot, the clearances are probably OK, although you should check them just so you will know, not be guessing.

 

Personally, if you are not about to take the engine apart and inspect every piece on a workbench, I'd cruise up to a local Yamaha dealer and have somebody that looks like they give a sh!t have a listen for you.

 

Actually, if the clearances are off, they typically are too tight, and that will not make any weird noises in most cases.

Edited May 22, 2014 by YZEtc

[BushRooster]

I own a '02 yz250f.

It has a rattle, my friends bike, same bike, similar rattle.

I have been worried but after 20+ hours trail riding, the rattle hasn't gotten better, or worse.

I've done oil/filter changes and it all seems fine.

A mate said he knows of later model yz250f's and 450f's that have had similar noises since new. And this fella has raced, and been around the traps for years.

If it gets louder for some reason, I'll stop riding and inspect the bottom end. But until then, it seems fairly normal. Just a noisy little thumper

Edited May 22, 2014 by BushRooster

[BushRooster]

Ps, what is the grey wire mod??

[flyandride]

I have the same bike and year, plated.  Nice that you got one that was completely stock and corked up as you know it couldn't have been thrashed much.  Unless you pulled the cam chain out and checked every inch of it, it may have a kink that hits the guide as it goes around.  As was the case with mine.  I replaced the chain and the tensioner with a manual one and adjusted so there is no noise.

 

The flywheel rivets also let loose on mine.  I had it mig welded, in your case I would do it before it lets go as this is a common problem.  

The stock pipe is very loud with the baffle removed.  Even with GYTR tip it was too loud.  I got an FMF Q4 and megabomb and the sound is reasonable.  

You'll also want to pull apart the suspension linkages and grease or replace the bearings and bushings.  They come with very little grease and often rust if not maintained.  

[Lunendan]

I did already change oil and filter.  Oil was decent and clean of any metal, filter was decent too.  My employee at work has the small feeler gauges that I need.  He is going to bring them in tomorrow.  I will pull the cover and check them this weekend at the campsite while relaxing.  He has the manual too for his yz.  I do have the ability and knowledge to remove and dismantle the engine completely, but I would rather not if I don't have to.  That is why I am asking here, to see if it is common and others experience this.  Similar to many people having the problem with the flywheel rivets loosening up.  I wish that were the case here. 

 

I will continue to ride and if it grenades, then I will have to disassemble.  It seems like a few people also seem to have noisy wr's.  I have seen it in a few other threads.  I will experiment and ride my buddies yz250f and try to recreate the same driving conditions that mine makes the noise, and see if his does it. 

 

I will further inspect the timing chain when I check the valves.  I will try to shine a light down and check the guides too with a mirror.  I will inspect the rear suspension too when I get a chance too.  Thanks for the tip fly. 

 

I will let you guys know what I find after the weekend.  Thanks for the responses. 

[Toby_S]

Loose Flywheel rivets can cause a sound that sounds like rod knock on some bikes. This is unique to the '01 and '02 WRs. There are lots of threads on it. Search "Toby" and "flywheel" and you should find them.

 

Also, there is chain slap under certain loads.

 

-Toby

Edited May 22, 2014 by Toby_S

[not2shabby]

My 03 WR is noisey too. It has a bash plate which makes it worse. I've checked the valves and changed oil several times now and have put around 30 hrs on it since I bought it last summer. I'd say ride more, worry less. Definately check the valves though.

[Lunendan]

Thanks for the tip Toby.  I have already removed the flywheel and checked it and the stator.  Everything is tight and right. 

 

Chain slap is a possibility.  I will also have to remove the skid plate and make sure it is not resonating under certain load. 

 

BushRooster the gray wire mod is; coming from the black box(cdi?) on the right side of your steering tube, one of the harness wires, a group of two, a black/white stripe, and a gray, remove the gray from the plug and tape it up to remove it from the system.  You are essentially un-grounding it, and it causes the bike to revert back to the stock yz250f ignition map.  With the gray wire part of the circuit, it runs the bike on a different ignition map which tones the bike down slightly, verses a motocross mapping. 

[lucgallant]

Chain slap is very misleading. I found that to be surprising to me but only really happened when lugging:

 

https://www.thumpertalk.com/topic/685207-chain-slap-on-08-wr250f/?hl=%2Blucgallant+%2Bchain+%2Bslap#entry6925988

 

If safe to do so, look down on chain and see if it is slapping. Or, speed up and see if it stops. Maybe setup a gopro watching the chain on top of the swingarm as it approaches the front sprocket. 

[Lunendan]

Here is the latest update folks.  I checked my valves this weekend.  Intakes are .007, exhausts are .005.  So they are a little tight.  Hopefully this weekend I can pull it apart and see what shims are in it now, and order the ones I need. At least they are not too far off the mark, but far enough to need to bring them into spec. 

 

My drive chain was pretty loose.  I was about 2.25 inches at the swingarm slider/protector rear bolt.  I brought it back to the beginning range of 1.6 inches.  I could not really look down to see it there was any slap or chatter because it was raining and my glasses were wet and covered while riding in today.

 

I rode to work today after dropping of my truck at the Ford dealer.  Same noise at the same driving condition.  It is an intermittent rattling/knocking/clatter sound that seems to be coming from the engine.  I guess I will just have to live with it and see what happens.  I think it is just a case of that these motors do not like to cruise at a steady speed at a reasonably low rpm.  I guess it would much rather be wound right up and ripping.  Which is fine, but not so much when riding on roads at constant speeds.  I just need to spend more time in the woods hammering on it ?

[BushRooster]

Cheers Lunendan. Thanks for explaining the grey wire mod.

[Lunendan]

No sweat Rooster.  Do the exhaust cam too.  Makes a big difference.

 

Here is the latest update.  I rode home from work last night, and finally it was decent enough weather to see.  I was able to look down on a quiet road when it was making that noise, and sure enough, It is drive chain slap on the swingarm.  Hard to believe for me that one, a drive chain will do that and hop up and down and wack the swingarm guard like that, and two, that it makes so much noise throughout the whole bike.  It sounds so much like the engine is going to grenade.  I guess the sound travels through the sprocket, into the transmission and engine.  So I will order a new swingarm slide/guard(it is deeply grooved from the chain but not through to metal), and adjust my chain to see if I can get that to go away, or at least quiet it some.  I have read to apply silicone between the swingarm guard and swingarm, so I will do that also.  I'll post if this works after I order a guard and install it. 

 

Thanks for the help on this guys. You were right Toby and gallant. 

[YZEtc]

I've found that on both my 2009 WR-250F and the 2002 model I still own, it will do that only when you are at a pretty low RPM.

The silicone sealant does help quite a bit with the noise.

[Lunendan]

Here is the latest update.  Sorry it has been so long.  I shimmed my valves, and replaced front and rear chain guards/guides.  I used some heavy rtv to coat the inside of the swingarm chainguide before installation.  I also installed my fmf q4 muffler and pb header.  The chainslap is mostly gone and much less noticeable and much less often.  I find that with the quiet fmf exhaust, I am able to ride at a higher rpm and lug the bike down much less.  I jetted the bike up a bit, and it seems to be a little rich.  I don't need choke to start, and even need the hot start to start cold.  So I may have overshot the need on jetting and have to step down.  But it is running great and an absolute blast to ride.  So I am pleased with my purchase and finally enjoying it.  Also getting to leave the 1 ton at home a few days a week is an added bonus to the wallet.  Thanks for the all the input.  I will try to upload a pic. 

 

 

 

 

[oldnbold]

My 1st thought was the chain slap issue. Glad that's all it was.

Way back in 98 I rebuilt my yz400f thinking chain slap was rod knock.

i learned!