03 WR450 need engine help


15 replies to this topic
  • Longtimeyamahaguy

Posted August 05, 2009 - 06:18 PM

#1

Bought this bike back in 2005 used. Had been run hard and put away wet a few time is suspect. I`ve turned this bike into a street legal supermoto. I changed the oil in it last weekend, had alot of metal chips on the filter. I always have a few chips on the filter but this time there was about 2-3 times as much. The supermoto project took about 2yrs to complete. When I parked the bike it never had a starting problem, since firing it up a few weeks ago it doesn`t like to start. I have to kick and kick and kick it over, often with a backfire before it will start. This is with a spotlessly cleaned carb. I know I`m jetted rich. 50 pilot, 170 main, red JD fuel screw 2 1/2 turns out. It always seems like the bike is lean. All the free mods have been done. YZ exhaust cam. FMF exhaust with a powerbomb header. Tonight I tore the engine down in hopes of finding the metal chip problem. I haven`t found that problem yet. Here is what I`ve found. Top ring gap is .024" bottom ring gap is .041" and the oil ring is at .040" Intake valves are at .005" and the exhaust vavles are at .009" Piston has some play. I have not measured the piston or the cylinder for size and ovality. But I still haven`t found the metal chip problem. I`m not really up for the idea of splitting the cases right now. Anyone have any insight on the location of the metal chip problem? Thanks for any help.

The head
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The piston
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Cylinder has some light scratches
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The exhaust valve stem
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Inside the header
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Inside the head pipe looking from the mid pipe joint, the white stops right at the end of the powerbomb piece.
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  • nitronaf

Posted August 05, 2009 - 06:48 PM

#2

get all the carbon off and check to see if those 'cleaned areas' on the intake valve indents have been kissing ur valves. Seems very strange to me and it aint normal.

No idea what that white stuff is.

I use my 06 in the same way as you. (sport bike hunter)

Oh and i use CRC gasket remover to get all the carbon off.

  • ncampion

Posted August 05, 2009 - 08:07 PM

#3

Looks like intake valves touching the piston. Are the In valves straight? Seems like a loss of compression should be evident.

  • wobblyknobby

Posted August 05, 2009 - 08:51 PM

#4

Man are you lucky you tore that down when you did. :thumbsup:

Your piston is so loose that it is rocking enough to touch that center intake pretty hard.

You need to make sure the lower rod bearing is not too loose. Check your bore for taper or out of round. Put new piston in a good cylinder. Check or r&r guides. Replace all 5 valves, seals and springs, cam chain and spark plug.

You could be back in action for about $500 if you figure out where the chips are coming from. It could be from the clutch or clutch release bearing. You do not need to split the cases to fix that. Pull the side covers and look for hatred. How are the cam journals?

Do you have a pic of the chips?

Check the flywheel so you can see what is stuck to the inner magnet. There should only be a thin grey layer of metal on there on there.

  • slowfe

Posted August 06, 2009 - 06:20 PM

#5

before everybody starts assuming that the intake valves are hitting the piston, he did say that the bike ran before he tore it apart. I would suspect the clean valve reliefs on the piston are from the intake charge coming in to the combustion chamber with raw fuel and that is why the piston is clean on the intake side. It also does look like he may have been burning some oil. Im not trying to say what is or what isn't. I don't want the guy led in the wrong direction cause of some clean marks on a piston. I would check the big end of the rod and the small end for and excessive play and go from there. Just my two cents. Also for what its worth my buddy has a 2000 wr400 and he is also always wondering why he finds some metal shavings in his filter. I think these shavings are more from the trans. side than the engine side. due to the fact he has a crap ton of hours on his and has never had a failure yet.

  • nitronaf

Posted August 06, 2009 - 06:23 PM

#6

before everybody starts assuming that the intake valves are hitting the piston, he did say that the bike ran before he tore it apart. I would suspect the clean valve reliefs on the piston are from the intake charge coming in to the combustion chamber with raw fuel and that is why the piston is clean on the intake side. It also does look like he may have been burning some oil. Im not trying to say what is or what isn't. I don't want the guy led in the wrong direction cause of some clean marks on a piston. I would check the big end of the rod and the small end for and excessive play and go from there. Just my two cents. Also for what its worth my buddy has a 2000 wr400 and he is also always wondering why he finds some metal shavings in his filter. I think these shavings are more from the trans. side than the engine side. due to the fact he has a crap ton of hours on his and has never had a failure yet.


+1
i agree

  • Longtimeyamahaguy

Posted August 07, 2009 - 10:14 AM

#7

I did forget to mention that it has been burnin some oil. I do not believe that the valves were hitting the piston. I`ve had the motor spinning 10,000 plus RPM. I`m pretty much set on just cleaning everything up and putting a new set of rings and possibly a new timing chain in it in hopes to get me through the rest of the summer. I`ll plan on a complete rebuild over the winter. If it breaks between now and then, well, I`ll just have more to rebuild then.

  • tp3dxf

Posted August 07, 2009 - 11:44 AM

#8

All my YZ250 oil burners had a cleaner piston surface the that. I'd say your burning a decent amount of oil for sure. Not sure if it's rings or valves but something isn't right. Good that you tore it down when you did. Let us know what you find out.

I suggest that you do the rebuild now. You've got the engine apart do it. If this thing fails your in for a lot more work come winter or whatever. Oh and a lot more money. Fix her right I am sure she deserves it.

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  • wobblyknobby

Posted August 08, 2009 - 09:46 AM

#9

before everybody starts assuming that the intake valves are hitting the piston, he did say that the bike ran before he tore it apart. I would suspect the clean valve reliefs on the piston are from the intake charge coming in to the combustion chamber with raw fuel and that is why the piston is clean on the intake side. It also does look like he may have been burning some oil. Im not trying to say what is or what isn't. I don't want the guy led in the wrong direction cause of some clean marks on a piston. I would check the big end of the rod and the small end for and excessive play and go from there. Just my two cents. Also for what its worth my buddy has a 2000 wr400 and he is also always wondering why he finds some metal shavings in his filter. I think these shavings are more from the trans. side than the engine side. due to the fact he has a crap ton of hours on his and has never had a failure yet.



:ride: :ride: :banana:

GET A CLUE DUDE! The piston is hitting the intake valves.

"Im not trying to say what is or what isn't. I don't want the guy led in the wrong direction cause of some clean marks on a piston". :thumbsup:

This is not theory, it is obvious. geeeez!:worthy:

  • wobblyknobby

Posted August 08, 2009 - 09:49 AM

#10

I did forget to mention that it has been burnin some oil. I do not believe that the valves were hitting the piston. I`ve had the motor spinning 10,000 plus RPM. I`m pretty much set on just cleaning everything up and putting a new set of rings and possibly a new timing chain in it in hopes to get me through the rest of the summer. I`ll plan on a complete rebuild over the winter. If it breaks between now and then, well, I`ll just have more to rebuild then.



Wow, really? Good luck. :thumbsup: :worthy: :ride:

Make sure you ride near the truck. :ride:

  • slowfe

Posted August 09, 2009 - 07:59 AM

#11

sounds to me like you need to get a clue. That engine spins at 10,000 plus rpms, any kind of contact with the valve at that kind of speed would cause catastrophic engine failure. You obviously have someone else work on your bikes. It sounds like you need to read up on the internal combustion engine, valves just don't hit the piston and leave clean marks on it. ANY KIND OF VALVE TO PISTON CONTACT AT HIGH RPM = BANG:bonk:

  • Longtimeyamahaguy

Posted August 09, 2009 - 04:17 PM

#12

AT HIGH RPM = BANG. Exactly. I tore the motor down when I thought I heard the cam chain doing some slapping and with the chips on the oil filter.

I have found the chip problem. Seems the previous owner had the valve cover off at some point and lost the little chain guide/bumper that is suppose to be on the valve cover.
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Also, does this nut have to come off to get the flywheel off? I`ve tried a electric and air impact with no luck, I even put just a little heat to it.
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  • slowfe

Posted August 09, 2009 - 05:22 PM

#13

Thats good to hear you found the issue. I was not trying to start a war with my suggestions, just trying to help you out. Iam just glad you found the issue, and hope you fet it running soon.:thumbsup:

  • slowfe

Posted August 09, 2009 - 05:27 PM

#14

It does look like the nut has to come off. I know on my freinds 400 the nut has to be removed, im pretty sure yours does to. the threads back behind the nut, i think are for a flywheel puller to attach to. You will probably have to order the yamaha tool.

  • wobblyknobby

Posted August 11, 2009 - 10:31 AM

#15

Those intakes are barely touching. They are getting closer little by little. When you put the new chain in, you may buy yourself a little clearance but only for a short time.

4 things bring the intake valves and piston too close: piston rock, loose cam chain, loose rod bearing, old valve springs.

Is there any up/down play on the big end of rod on the crank? Hopefully there is not.

Your piston is worn out if your rings are that worn out. This is critical to stop the rocking and valve clearance problem. You need a piston. On e bay you can get a pro-x piston w/rings and top end gaskets for $125.

Next issue is those valves. The clearance problem you refuse to admit you have has probably worn your valve locks and maybe the hard surface. On e bay you can get 5 stainless valves and springs for $110.

Running the valves as they are is really rolling the dice since they are already showing signs of distress.

Look at my 1 year old piston with a valve jammed thru it upside-down. See the contact marks in the valve relief? If I had taken this apart an hour before it blew, it would look just like yours! The piston is newer than yours but worn out.

Valve float and/or insufficient piston to valve clearance comprimised the valve locks and retaining groove, then the valve dropped.

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BTW, I am a pro engine builder so I understand what happens when valves hit pistons. Now you need to understand that there is a point when they are barely touching and about to cross the threshold of failing. That is where you are.

Just trying to help. :thumbsup:

  • leethal

Posted September 05, 2009 - 10:46 PM

#16

It maybe a litle late .. But you have already removed the nut that holds flywheel on ... you need a puller now 30mm x 1mm thread which screws onto the wheel ... it has a bolt which pushes onto the center shaft .. put the nut back on to protect the thread on the crankshaft ... ... also replace everything valves... springs ... piston ... chain .. even the rod etc seems you ride pretty hard




 
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