YZ450f 2010->2016 connection rod part #

Yes Pressure and volume are different but they have each a great effect on the librication system,

Chevrolet Racing further discovered that no more than 45 psi of oil pressure was ever needed for any reason.  Bear in mind two things as we ramble down this side road: First these are 600+ HP (sometimes way +) small block V8's, not stock engines, and second, they're predominantly plain bearing engines.  The YZ450 is predominantly rolling element bearings that can live with no oil pressure whatsoever (and indeed, cannot contain any pressure) as long as they get a supply of oil.  In fact, the main bearings in the YZF have no direct oil feed delivered to them at all, just incidental oil from drainage.  The only place in the engine that are pressure fed is the camshafts.  The rod bearing is directly fed, but it's a metered amount, and there isn't any pressure in the part of the circuit between the nose of the right crank axle and the con rod because, as I have said, the bearing won't hold any.

 

The other factor that remains is that oil pressure as nothing whatever to do with the lubrication of the rod small end, since everyone's small end bearings are lubed by indirect means like oil thrown off by the big end. In engines with floating, rather than pressed in wrist pins like the YZF and most other bikes, most of the actual movement between parts takes place between the pin and the bores in the piston, and very little in the rod small end.  IF there is in fact a defect with the '14 rod small end, it will be one of these:

  • The clearance is excessive, allowing the wrist pin to "rattle loose" over time because of a manufacturing error
  • The clearance is excessive, allowing the wrist pin to "rattle loose" over time because of an incorrect specification by the engineers
  • The materials used in the rod and wrist pin are incompatible to the task at hand
  • The design of the rod small end is such that is interferes with oil entry
  • The design of the rod is simply too weak

If the condition is such that one needs to choose or avoid a certain oil over others when all of the oils considered meet the manufacturer's requirements, it's not the fault of the oil.

There is no indication that oil had any effect on the failure of the rod in my engine. Bearing surfaces look immaculate on the remaining pieces and there was no noise prior to its failure.

There is no indication that oil had any effect on the failure of the rod in my engine. Bearing surfaces look immaculate on the remaining pieces and there was no noise prior to its failure.

 

Any pics of the failed rod?

I have a 2014 yz450, I replaced the connecting rod in Dec 2014 for a piece of mind from my top end getting damaged. 

 

Anyways i had about 45 hours on the original connecting rod, then it was replaced with the new PN and has about 70 hours on it. with GYTR head, Cams and hi-comp piston.. No issues. and i am pretty sure i would have had no issues with the original one either. 

Any pics of the failed rod?

Forgot to grab a picture of the rods bearing surface but here's some pics of the rest of it:

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I'll bet that made a noise.  The head's not so bad, though, eh? 

All 4 valves are bent but other than that the head is fine. So i have a head and a clutch. Not much left

What did that head come off? Not a 14-16 yz-f.

What did that head come off? Not a 14-16 yz-f.

14 YZ450F

What did that head come off? Not a 14-16 yz-f.

 

Why not? 

Why not?

I forgot they switched to 4 valves heads on the 450 awhile back. My bad.

From 2010 upward.  That head, more than any of the other improvements to the engine, is worth 6-7 HP over the 5-valve setup. 

So from what's left, it looks like the small end of the rod failed across the oil holes

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Does anyone know what the new rod has for updates? Bigger oil holes perhaps?

So from what's left, it looks like the small end of the rod failed across the oil holes

Does anyone know what the new rod has for updates? Bigger oil holes perhaps?

what if the wrist pin was undersized and rattled, naturally the rod end would break at the weakest link which is where there is less material. That sucks....

what if the wrist pin was undersized and rattled, naturally the rod end would break at the weakest link which is where there is less material. That sucks....

 

Since they haven't changed the wrist pin either before or after the '14 model, I have to say that it's more likely the rod was oversize rather than the other way 'round.  

 

I believe another member here reported his was noisy prior to being replaced.  

Since they haven't changed the wrist pin either before or after the '14 model, I have to say that it's more likely the rod was oversize rather than the other way 'round.

I believe another member here reported his was noisy prior to being replaced.

that would be noisey! When my crf upper end went bad on the rod I heard it loudly and it was barely out of spec, just galled

Mine wasn't noisy, sounded exactly the same as the 15 yz450f that was sitting next to it. Got a 16 YZ250F yesterday, hope it lasts longer...

Parting the 14?

Yeah partial part out. Building 250 2 stroke with a lot of it

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