White/Blue Smoke on throttle - 07 450fw

Yamaha YZ450F 2007

43 replies to this topic
  • i want to ride

Posted November 04, 2013 - 03:40 PM

#21

you know there's an easy way to find out whether its due to the packing just remove it. Good luck

  • i want to ride

Posted November 04, 2013 - 04:46 PM

#22

Gray bring up a good point, check air filter area for any oil.from someone applying it to filter dust wrap could be sucking in during wot.

  • fldrifter

Posted November 04, 2013 - 04:48 PM

#23

What do you mean applying oil to the air filter?

  • i want to ride

Posted November 04, 2013 - 05:02 PM

#24

Just thinking out of the box. Air filter has what i call a dust wrap which after cleaning it you apply filter grease you problem know all about this but i was thinking if someone used oil you may be sucking it in. Most like not but doesn't take long to check.just trying to be helpful

  • fldrifter

Posted November 05, 2013 - 07:22 AM

#25

Just thinking out of the box. Air filter has what i call a dust wrap which after cleaning it you apply filter grease you problem know all about this but i was thinking if someone used oil you may be sucking it in. Most like not but doesn't take long to check.just trying to be helpful

 

 

oh ok, no I put a new NoToil filter on with NoToil filter grease sealer on the lip.  I will look at the bike tonight, as I did not get a chance last night. 



  • grayracer513

Posted November 05, 2013 - 07:36 AM

#26

Just thinking out of the box.

 

Way outside.

 

You are talking about the flange seal on the filter element, and I never grease mine anymore.  Haven't for years.  The filter oil I use (Maxima FFT) seals this area better than grease for one thing, is much easier to remove than grease when cleaning, and there is absolutely no reason whatever that oil from the flange would be more easily drawn into the air stream than oil from any other part of the element.

 

Filter oil needs to sit in place, preferably outside the air box, for a good 5 or so hours minimum in order that the volatile vehicle components (the light solvents that help carry the oil into the foam) have a chance to evaporate, leaving only the thick, sticky filter oil behind.

 

In any event, when an excess of oil is used, or inadequate dry time is given, what normally happens is the air jets at the carb mouth become plugged and you have obvious performance problems.  Air cleaner oil wouldn't be enough to cause a continuing smoke problem anyway.



  • fldrifter

Posted November 13, 2013 - 03:44 PM

#27

Ok, finally got back to the bike tonight.

Started it up, no issues like before. No smoke on startup and let it warm up a couple minutes/ shut off and did oil check. My oil level is showing half full. After about a minute it all drains back down and I can't get a reading, which I understand is normal. I rechecked the oil again after starting the bike up and again showing half full.

So, I have no visual leaks on the outside, I'm clearly burning through the motor, but this time there isn't any big plumes of smoke like before. Now, I have ridden the bike 2 times before the oil change that showed whatever problem I had. When I did my oil change I only got 1/2-3/4 quart out of the system with old oil.

So what in the engine would cause this to burn to the top 1/4 amount of oil and then seem to taper off when it's half to 2/3 full?

I need to rebuild the top end on this don't I....... Or at least a rehone and new ring. ......

Edited by fldrifter, November 13, 2013 - 03:46 PM.


  • grayracer513

Posted November 13, 2013 - 05:16 PM

#28

So what in the engine would cause this to burn to the top 1/4 amount of oil and then seem to taper off when it's half to 2/3 full?

I need to rebuild the top end on this don't I....... Or at least a rehone and new ring. ......

 

Nothing I can think of, short of something really rather odd. 

 

There are normally only two ways for oil to get into the combustion chamber to get burned: rings and valve seals.  Head gaskets can leak oil into the chamber, but they normally cause other more noticeable problems first.



  • fldrifter

Posted November 14, 2013 - 06:52 AM

#29

Nothing I can think of, short of something really rather odd. 

 

There are normally only two ways for oil to get into the combustion chamber to get burned: rings and valve seals.  Head gaskets can leak oil into the chamber, but they normally cause other more noticeable problems first.

 

Well, I guess I will ride this weekend and then go ahead and take the top end off and check out what I need to order.  Thanks for the information!

 

Is there anyway to check the valve seals at all? or is that just a replace them type deal?  I'm guessing it would be the valves, if the prior owner did do a top end, then he most likely never touched the valves. 


Edited by fldrifter, November 14, 2013 - 08:19 AM.


  • yamaha-hillclimbs 15

Posted November 14, 2013 - 10:22 AM

#30

I would just replace valve seals probly not an easy way to check them for 100%. I had a similar problem and it turned out that the super smart and talented people who did my engine didn't even put valve seals in! Super special huh? I would check if there even there to start.

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  • grayracer513

Posted November 14, 2013 - 10:37 AM

#31

Oops! :blush:

 

Well, at least you didn't need to worry about a lack of lube in the guides.



  • yamaha-hillclimbs 15

Posted November 14, 2013 - 10:41 AM

#32

Hahahah true very true

  • i want to ride

Posted November 14, 2013 - 11:24 AM

#33

Buy new seals for sure and mic the valve stems for any wear check your manual for go no go. Should be able to check end gap on rings before any work has been done also check manual for go no go. Check ring end gap at top middle bottom. Hope this helps

  • fldrifter

Posted December 15, 2013 - 09:00 PM

#34

Ok, I have an update here on the bike, plus lots of pictures.

 

I started the bike the other day and ended going for a short ride without any issues, until the last five minutes of the ride when I stopped and shut off the bike.  When I attempted to kick it over, the kick starter was frozen, I rocked the bike a few times and it allow me to kick it over and the bike was fine.  Fast forward to today, where I attempted to kick it over and it was frozen up solid.  If I put some weight on the kick lever it would bump free and rotate down, but if I attempted to try and kick, it wouldn't budge.  I waited till I took the top end off/trans cover before messing with it anymore.  There is a picture below showing the kick gear/spring, I'm not sure if the spring is normally supposed to be a bit oblong on the last coil or not.  However, I did break the kick level seize by using a wrench on the crank side, It would rotate freely 3/4 of the way either way before stopping, I ended up bumping it with the wrench and it popped free, which it now rotates freely all the way around, by hand and with the kick lever.  Any idea what is worn/broken that would cause this to seize up? 

 

Things I made note of when taking down the top end/ trans cover:

1) top of piston has caked on deposits/ definitely from the oil burning

2) piston rings look perfectly fine, this top end should only have 10 hours on it tota, if the guy who I bought it from told the truth about riding it 2 times before I bought it.

3) cylinder looks fine, only 1 spot at the top of the cylinder (photo is below) which has a mark, I have not attempted to wipe that area, Im guessing its from burning oil

4) valves have a ton of caked on oil deposit

5) no metal chunks/pieces in the oil when drained

6) no metal bits in the trans case side when I took it apart

7) there is no play in the piston rod to crank, either side to side or up and down.

 

- I have not taken the valves out yet, but it appears to me it was the valve seal leaking oil

 

Question time-

1) Can I get away with a new head gasket and just putting the cylinder back on the bike as is?

2) What do I need to look at that would cause the kick lever to seize up?

3) When I clean the valves off, do I hit them with soap and water and a light scrub brush?  Dawn dish soap good to use?

 

mark on the top of cylinder head

[imgur](http://i.imgur.com/OSaqZaq)

 

rest of cylinder

[imgur](http://i.imgur.com/KY8G36W)

 

[imgur](http://i.imgur.com/Mwhzmke)

 

[imgur](http://i.imgur.com/DhVQZqg)

 

[imgur](http://i.imgur.com/z2J3NQp)

 

piston

[imgur](http://i.imgur.com/PYnsNh0)

 

[imgur](http://i.imgur.com/cdKbkDq)

 

[imgur](http://i.imgur.com/mtdtzEE)

 

[imgur](http://i.imgur.com/qQfzWXN)

 

kick level gearing & spring - last coil is out of round from the rest

[imgur](http://i.imgur.com/34b2rUf)


Edited by fldrifter, December 15, 2013 - 09:04 PM.


  • yamaha-hillclimbs 15

Posted December 16, 2013 - 10:55 AM

#35

So when you buy a new cylinder do you just slap it together and its good to go?

  • grayracer513

Posted December 16, 2013 - 11:10 AM

#36

New Yamaha cylinders are ready to use as issued, yes.



  • fldrifter

Posted December 16, 2013 - 11:28 AM

#37

Greyracer, any input on my post above?

 

I know I need a new head gasket, hoping I can get away with not honing my bore and needing new piston rings.

 

Thanks!



  • NitrousR1

Posted December 16, 2013 - 03:34 PM

#38

Personally with a bike burning oil I would replace the rings while your in there. For the oil burning It's either the rings or valve seals or possibly a worn guide- but very unlikely on these bikes.
I'd replace all 5 valve seals- I do stock them if you need them. Find out what brand piston it is, scrape off the carbon and see if there's a part number on the top of the piston, or on the underside of the piston. You must buy the rings for that make of piston. They are not interchangeable.
Also you should measure the piston, then you can see if it really was replaced- i dont believe anything previous owners say until i prove it. For me its a waste of your time not to replace the rings when you have a oil burning issue.
Was the timing correct before you pulled the head? Spin the crank by hand and feel for any roughness or binding in the bearing.
You said the crank has no side to side play. It has to have some and you need to measure it. Compare your measurement with the spec in the manual. If its past the max limit replace the crank and bearings.

  • fldrifter

Posted December 17, 2013 - 08:24 AM

#39

I took all the valves out last night and cleaned them up.  The 3 intake valves looked decent with carbon build up, but it all came off easily.  The 2 exhaust valves, had the bad seals.  1 of them had a ton of carbon build up on the back side, these 2 are about 80% cleaned up now, it seems to have layers and layers of carbon caked on.  The seating faces are all 100%, even when I took them out.  Nice and polished up, I gave them a quick wipe to clear any deposits off.  The valve head cleaned up easily and I scrubbed out the exhaust port a little bit to remove the loose deposits.  

 

I have not touched the piston yet for cleaning as it has not been removed from the motor. I know it is aftermarket, but haven't looked to see what brand.  I know the cylinder/piston was replaced because I have the old cylinder/piston that came with the bike. 

 

The timing was fine before I pulled the camshafts and everything out.  The bike ran like a champ, the only problem was the burning oil from the valves.  I'm wondering if the oil was to low on the last ride and something bound up on the kick starter.   It is freed up now, but I have no idea what I need to check on the bottom end for where the kick lever has connecting points.  I can see the gear/spring mechanism, but is there something on the back side of the housing that it connects to that could bend/warp, etc? 

 

Nitrous, thanks for the offer on the valve seals, I have 5 oem ones on hand.  Once, I freed up the kick lever, the crank spins by hand with no dragging feeling.  Before I freed the kick lever, I could rotate the crank 3/4 left or right without issue and then it would "hit a wall" and not let it rotate.  I gave it a solid bump with a wrench and now it rotates 360* freely without drag. 


Edited by fldrifter, December 17, 2013 - 08:27 AM.


  • NitrousR1

Posted December 17, 2013 - 09:43 AM

#40

Unfortunately all you can do to check the bottom end is to spin the crank by hand and listen/feel for binding and roughness and checking side to side play.
Excessive side to side play can let the rod tilt. Measure it and compare it to the spec in your manual. If its close to max replace the crank and both side bearings. It is a very important measurement. Of course ANY up/down play and it needs replaced ASAP.
Also you can look around the clutch basket, kick starter gear area for anything that would bind up, but that's all you can do.
After that you have to replace the crank and bearings. Also wise to replace all the transmission bearings too while your in there





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