Need advice about my 426 PLEASE!

Yamaha WR426F 2001

40 replies to this topic
  • ThumpMe

Posted March 21, 2015 - 01:39 PM

#21

The oil almost always looks and gets a little thicker, darker, and dirtier looking at the bottom as it tends to settle out the bigger particulates as it sits.

 

 That oil does not look that bad to me. The fact they are saying your bike had metal floating around in the oil when it does not would be enough to make me either start looking for a new shop or start doing your own maintenance. That shop sounds like it it trying to drum up some business....at YOUR expense!

 

 It really is not that hard....ALL of us had to start somewhere, and back when a lot of us did, we did so with ONLY shop manuals, help from fathers, and or friends,....and a little common sense. NOW with the internet we are all able to solicit help, criticism, good AND bad advice, but most of all keep our scooters running while learning things and hopefully saving a pocket full of $$!

 

 I would steer clear of that shop FOREVER ........or till they get new management....which probably will not be to long if they are pulling that kind of garbage on customers.

 

 I think you are on the right track....check the valve clearance as you do not even have to tear anything down to do that, just pull off the valve cover,  then make a decision on what to do from there.

 

 I still think it will be something simple due to the way it died on you.

 

 No compression for the most part can only come from a few things like ....compression release out of adjustment, bad ring/s,or out of adjustment or  bad valve/s.  Since it was runningand just quit I have a hard time believing it is rings or valves, but it could be. Or possibly the timing jumped....... but that is not very common either.

 

 ALWAYS try to start with the simple things. Nine times out of ten THAT is where you will find the problem! 

 

 Good luck, keep us posted.



  • gregnextdoor

Posted March 21, 2015 - 04:12 PM

#22

holy &%$#@!ing shit guys....... I want to say "you don't know the dragon of excitement building within me," but I think you all thumpers do!

I may have found physical evidence of a critical issue....

 

I took off the valve cover, and here is no alignment mark on the flywheel when I'm at top dead center. There are the three marks on the cam cogs like there should be, but when they are at the top, there is no mark on the flywheel through the viewing hole.

I spun the thing around a few times, looking for the mark on the flywheel regardless of cam position, and I haven't been able to determine where it is. What I can see through the viewing hole is: a few different holes, an arrow pointing in the direction of rotation, and an ingraved "HI". Whichever of these is my TDC alignment mark, neither are in the correct position.

 

Here's what it looks like:

 

Looks like I should get this thing back in time?

Attached Thumbnails

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Edited by gregnextdoor, March 21, 2015 - 04:15 PM.


  • gregnextdoor

Posted March 21, 2015 - 04:28 PM

#23

Ok I just found out that the "I" in "HI" is my flywheel alignment mark.

When I put the it in the right position, my cams are almost exactly upside down.

I'm going to the gettin' place right now, to get some feeler gauges.

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  • gregnextdoor

Posted March 21, 2015 - 05:31 PM

#24

This is all coming to you in real time btw...

 

Got a set of feeler gauges.

Set the cams to top dead center.

Feeler gauges will go under both on the exhaust side.

Smallest feeler gauge will NOT go under ANY of the three on the intake side.

 

Smallest feeler is .203mm

Do I need a smaller set?

 

I should probably proceed with getting it back in timing alignment before worrying about valve clearance, even though I'll have to pull it back apart again, oh well...

 

Anyones thoughts?


Edited by gregnextdoor, March 21, 2015 - 06:31 PM.


  • Krannie McKranface

Posted March 21, 2015 - 06:11 PM

#25

Yes, you need .025 and up

 

Your clearances are going to be around .12 -.16 if I remember correctly.

 

You need a SERVICE MANUAL as this is not an area to continue guessing with.


Edited by Kah Ran Nee, March 21, 2015 - 06:11 PM.


  • gregnextdoor

Posted March 21, 2015 - 07:38 PM

#26

Ok this is where I'm at:

First off, I can loosen the intake cam cap bolts enough to get the feeler gauge between the bucket and lobe, but not the left one.

Anyway, I started taking off the cam shaft caps, and I noticed the intake side had tension pushing up on it the entire time the bolts were coming out. This made it difficult to even get the cap off, because it didn't want to come off of the chain because it was always pushing up against it. I turned the engine a little bit to ease some of the pressure, finally got the intake cam cap off.

What I found here troubles me, the left most bucket is raised significantly higher than the other two, due to the metal spring under the bucket. Cycling the engine does nothing that high up, without the cam shafts and timing chain installed, and the bucket just sits there, raised. I can push it down with my finger against the spring tension, but not the others.

Here's what I mean: You can see all 5 buckets, with the left side intake bucket much higher than the other ones.

WHAT DOES THIS MEAN???
 

Attached Thumbnails

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Edited by gregnextdoor, March 21, 2015 - 07:39 PM.


  • x_JT_x

Posted March 21, 2015 - 08:10 PM

#27

That left bucket looks like the shim has just slid once the bucket lifted, and that's why it won't go down. Take it all the way out, and reposition the shim.

If your timing is off, there will be constant pressure on the cams. But since you say the timing was 180 degrees off, then you have the bottom end on the wrong rotation..

Don't use the loosening of the cap to fit the gauge as any info worth using. It COULD mean you need smaller shims/new valve, but more likely has to do with off timing.

  • gregnextdoor

Posted March 22, 2015 - 06:57 AM

#28

That left bucket looks like the shim has just slid once the bucket lifted, and that's why it won't go down. Take it all the way out, and reposition the shim.

If your timing is off, there will be constant pressure on the cams. But since you say the timing was 180 degrees off, then you have the bottom end on the wrong rotation..

Don't use the loosening of the cap to fit the gauge as any info worth using. It COULD mean you need smaller shims/new valve, but more likely has to do with off timing.

 

You are right in saying that experiment is mostly speculation, and will not definitively solve anything, but I feel, at least from my position, it is a step in the right direction.

 

And actually those pictures are with the shim REMOVED from under that left bucket, it will ride a mm or so higher than that when I put it back in.

 

Attached now are the pictures I should have shown you on my last reply.

You'll see the culprit is not the bucket, or the shim. It is the metal spring under the shim, and whatever is beneath it, that is riding higher than the other 4.

 

What I'm going to do now is just try to get my alignment marks to meet up correctly on flywheel and cams and put it back together as is, and check the compression.

Attached Thumbnails

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Edited by gregnextdoor, March 22, 2015 - 06:59 AM.


  • x_JT_x

Posted March 22, 2015 - 07:57 AM

#29

It would appear from those pictures that the cotters are missing from that valve. In which case the valve should drop straight into the engine... Got a close up straight up and down pic of that area?

  • gregnextdoor

Posted March 22, 2015 - 08:17 AM

#30

It would appear from those pictures that the cotters are missing from that valve. In which case the valve should drop straight into the engine... Got a close up straight up and down pic of that area?

 

Ok if I take the spring out, the thing under it, I can kind of push down into the head, feels like pushing together a hydraulic arm, slow like moving through heavy grease, but not far enough in to match the other buckets.

I did find two tiny broken pieces of something under the spring, I think it's the "keeper" for that spring, am I wrong? That would make sense as to what's going on with this valve.

Here are pics of that, as well as straight down into the left intake.

Attached Thumbnails

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Edited by gregnextdoor, March 22, 2015 - 08:29 AM.


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  • x_JT_x

Posted March 22, 2015 - 08:55 AM

#31

Ok if I take the spring out, the thing under it, I can kind of push down into the head, feels like pushing together a hydraulic arm, slow like moving through heavy grease, but not far enough in to match the other buckets.
I did find two tiny broken pieces of something under the spring, I think it's the "keeper" for that spring, am I wrong? That would make sense as to what's going on with this valve.
Here are pics of that, as well as straight down into the left intake.



Massive red flag. Stop right there. The spring should NOT be able to come out without a valve compressing tool. And that is one of the cotters/keepers that has fallen out, and looks like parts of another. You MUST take that head off. You may get lucky and only need the one valve, but it cannot be ran again if it stalled out because of no cotter. Are you pushing on the valve itself that feels hydraulic? If so, then the valve is probably bent. Lucky for you, it appears the valve probably did not do any damage to the head besides the guide.

I had the same thing happen on an rmz450. But mine blew the bucket up top apart and almost messed up where the bucket slides. Even with more damage, it was repairable.

  • gregnextdoor

Posted March 22, 2015 - 09:07 AM

#32

Ok so I can put the good half of the cotter into the spring and compress the spring with my DIY compression tool (needle noses covered in tape,) and ALMOST get the spring to stay in place, but what I need is the other half of the cotter then it would be fine. I don't know about the valve being bent, but I think I should get a new cotter, the shim and bucket back in the right place, then test, before pulling off the head.

 

Is it possible for the cotter to simply break, releasing all tension on the spring and blocking all clearance at that valve, and instantly disable my bike? (without bending a valve)

AM I MAKING PROGRESS OR WHAT GUYS? I am so excited for this to be moving forward!


Edited by gregnextdoor, March 22, 2015 - 09:13 AM.


  • wes513v

Posted March 22, 2015 - 09:20 AM

#33

Ok so I can put the good half of the cotter into the spring and compress the spring with my DIY compression tool (needle noses covered in tape,) and ALMOST get the spring to stay in place, but what I need is the other half of the cotter then it would be fine. I don't know about the valve being bent, but I think I should get a new cotter, the shim and bucket back in the right place, then test, before pulling off the head.

Is it possible for the cotter to simply break, releasing all tension on the spring and blocking all clearance at that valve, and instantly disable my bike? (without bending a valve)
AM I MAKING PROGRESS OR WHAT GUYS? I am so excited for this to be moving forward!


You're not listening. If the the keepers popped off then the valve certainly dropped and got bent when it contacted the piston. You have a major issue that cannot just be back yard mechaniced back together to save you money. You need to pull the head, send it somewhere competent to be rebuilt(not your dealer) and hopefully it is not trashed more than what you see. I would replace the piston and timing chain at the same time, one because it contacted the valve, and two because you are already in there. Depending on the hours on the bike you might need to have the cylinder done as well.

Stop being excited because you are not moving forward at this point. Buy a manual if you don't already have one and follow it to the letter. Send your head to someone like FastHeads or Millenium.

  • Krannie McKranface

Posted March 22, 2015 - 09:30 AM

#34

He hasn't listened or read the repsonses since post one.........

 

That motor will be shooting pistons and vavles if he ever gets it started.



  • x_JT_x

Posted March 22, 2015 - 10:47 AM

#35

Ok so I can put the good half of the cotter into the spring and compress the spring with my DIY compression tool (needle noses covered in tape,) and ALMOST get the spring to stay in place, but what I need is the other half of the cotter then it would be fine. I don't know about the valve being bent, but I think I should get a new cotter, the shim and bucket back in the right place, then test, before pulling off the head.

Is it possible for the cotter to simply break, releasing all tension on the spring and blocking all clearance at that valve, and instantly disable my bike? (without bending a valve)
AM I MAKING PROGRESS OR WHAT GUYS? I am so excited for this to be moving forward!



No, it is not possible that the valve is not bent. I'll give you an example why.

The cam spins, pushing down on the valve. The cotters make it so the spring can pull the valve back up for the next rotation. When the cotters came out, the cam STILL pushed the valve down. Which means the valve was down the entire rotation. Don't bother messing with the valve, it's done. Not just the keeper. The entire valve. And for the price of a valve guide, it's not worth it to risk that one. It should only be about 15 for a guide and maybe 25 extra for the guide install, tops.

I give you credit, you are making progress. But from someone who knows engines it's fruitless to try and test stuff about that valve out. I believe that type of thing is the reason the others are mad. I'm not, because at least you are asking questions. Which is excellent.


Another thing is, your compression tool shouldn't work at all if the valve were healthy. A healthy valve would slide down into the motor without a cotter on it. The fact you are able to almost compress the spring without the valve going down just proves that you need a new valve. Keep working and asking questions, and I believe you will maintain your bike just fine.

  • JorisBoris

Posted March 22, 2015 - 11:01 AM

#36

You are learning fast for someone not knowing a lot about bikes. Don't get angry now, you'll get there.

First of all, the bike may be cheap ( 1400$) but that doesn't mean you should save money on replacements. Pull the head and check everything that may got damaged.
Good luck

  • gregnextdoor

Posted March 22, 2015 - 11:12 AM

#37

Thank you, JT. I really appreciate it! I understand what you mean, and it makes sense, about how the cotter keeps the valve from falling down into the head. I agree that the cotter won't be enough, that was just my optimistic hopes. It is true that I am an amateur, and quite unfamiliar with the deep workings of these engines, but even since the day I started this thread, my knowledge has increased drastically, with just the internet and tearing it all down slowly. I feel that taking the head off and doing the new valve installation is no longer beyond me. As for the piston and cylinder, that's an even farther step that I will have to assess when I get to that point.

 

JorisBoris, it is easy to get angry when someone tries to shoot down my hopes about something I care so much for and that excites me so much.

I don't think EITHER wes513v OR Kah Ran Nee fully understands the ecstatic joy of being in the wind on two wheels.

Thank you as well.



  • William1

Posted March 22, 2015 - 11:58 AM

#38

Get a service manual.

Reinventing the 'diagnostic wheel' is a waste of time and do not expect to find a brass ring.

You've found a bad valve on a old bike. Smart money is to decide to repair or part out.

Figure:

All five valves

Springs, cotters retainers

Valve seats cut or replaced

Here it may even be cheaper to consider a replacement head from APE or Big Bore Thumpers, all assembled and ready to shim and go.

New cam chain

New piston, rings, wrist pin, clips.

Inspect bore, it may need a replate.

If the valve contact to piston was hard enough to 'clean the piston', it may need a new rod, it then is cheaper to replace the rod and crank. You also do main bearings

Sundry other parts.

 

Price it out and be realistic. Consider how much you'll invest Vs. What the bike is worth. If you plan to ride it till the engine dies again, it might be worth it. But keep in mind the bikes age and 'sensibility' of it all. Many a person has bought a %1500 bike, put $2K into it and ended up with a bike worth $1,400 when smart money would of cut losses, sold out the dead bike and invested in something in better condition.

 

Always be VERY leery of used race bikes. Most owners do not take care of them and unload them when something is seriously wrong, often 'repairing enough' to make it run for 30 minutes.



  • x_JT_x

Posted March 22, 2015 - 12:01 PM

#39

Unfortunately, the valve installation is not something you can do yourself. These modern 4 stroke engines have to have the seats cut to fit the valves when installing new valves. If you use the classic way of lapping the valves, you will destroy the hard coating on the valve and it will zero out spec wise in no time.

Plus, the valve guide needs a machine shop. If you factor in the time you will spend working on it yourself, even if it were possible to do the valves yourself, you would find it cheaper to work a few extra hours at your job and have it done by a shop vs using your time to do it. And unless you have a buddy with a multi thousand dollar seat cutting machine, you are SOL on the home repair. I've had engines apart all the way many times. I will only attempt a valve replacement on stuff like the old XR motors since you CAN lap those valves in.

  • ThumpMe

Posted March 23, 2015 - 09:11 AM

#40

Wow, went out riding yesterday and this morning and check back in to find this thread exploded! No pun intended.

 

 As others have already mentioned, since that valve keeper came off something is way wrong. You  might get lucky and find the valve could still be good but I doubt it. Since you said you were motoring along in fifth gear I would imagine it probably bent the valve. It very well might have punched a hole in the top of the piston too, as when a valve drops down because a keeper has come off they will frequently hit the piston as it is on its way back up. This contact with the piston is usually also what bends a valve.

 

 It will have to be completely disassembled to be put right. 

 

 Get a shop manual, a good one. Some can be downloaded off the net but I always like to have a shop manual made by the SAME people who built the bike. Spend the $$ and get one, it will save you hours of grief and guess work. They usually all have pretty much the same information, but sine they built the bike, I like having one from the same manufacturer of it. 

 

 You can do a lot of the work yourself, but as mentioned too, some of the work  will require  a knowledgeable engine rebuilding shop. It will be expensive too, but the bright side is once completed you will have learned a bunch, and will have a lot more confidence in the bike running well.







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