Knock knock

[TownsendsFJR1300]

On page 2-25 of the Factory Yamaha manual (2007 manual) shows each rod bearing feed oil from an adjacent main bearing.

Each main bearing is feed oil thru the block eventually connected to a common main oil gallery.

Oil is pumped to the top of the engine from one end of that gallery as well.

Both rods not being adjacent indicate it probably wasn't a blockage or more bearings would be damaged or at least adjacent to each other.. A very close inspection would definitly be due...

 

[FinalImpact]

I think we are all raising good questions so I'll throw this out:
What are the chances someone over-reved this engine early in life, spun the bearings and it made this far???

Looking at the Rod caps you can see the bearing tangs were torn off two of the bearings when they spun. Sometimes the tang folds in and stays in place and sometimes it snaps clean. There is most likely 4 chunks to found. I mean some times they roll right back into place and stay with the shell. These two did not do that; Meaning they spun in the rods because they locked onto the crank long enough to rotate in the rod. (Not good)

Anyway, one avenue is if it spun the bearing, why trust it even if it meets specs? My thinking is, if it meets spec in every way shape and form, I may be tempted to use it unless its affordable to replace or there is low risk. You don't know anything about the replacement parts and then the whole thing will need to be balanced to survive. Example: replace the rods and grind the crank under. Then the new rods and possibly old crank all need to be balanced to match each other. So unless the parts are new, they may have suffered the same fate???? Just thinking out loud.

Agree - they all came from the same engine and from the oil diagrams, nothing stands out as to why those two would be starved. Thanks for Both of the diagrams by the way. I missed the one in the manual.

An internal oil leak could be what placed this in motion but here are more thoughts. Although we tend to think that loose bearings go first, they typically get the bulk of the cooling and lubrication because they are loose while tight rods/mains are starved because they don't "leak enough". The copper showing says it made contact with the crank lots of times and wore the lead babit away opening up the bearings oil clearance. In the auto world, this is found on neglected engines with few oil changes. Here, who knows. . . .

More thinking. . .

 

[04fizzer]

I think we are all raising good questions so I'll throw this out:
What are the chances someone over-reved this engine early in life, spun the bearings and it made this far???

You can see the chunk off the bearings was a break on the two visible, so maybe there are 4 chunks to found? I mean some times they roll right back into place and stay with the shell. These two did not do that.

Anyway, one avenue is if it spun the bearing, why trust it even if it meets specs? My thinking is, if it meets spec in every way shape and form, I may be tempted to use it unless its affordable to reaplce or there is low risk. You don't know anything about the replacement parts and then the whole thing will need to be balanced to survive. Example: replace the rods and grind the crank under. Then the new rods and possibly old crank all need to be balanced to match each other. So unless the parts are new, they may have suffered the same fate???? Just thinking out loud.

Agree - they all came from the same engine and from the oil diagrams, nothing stands out as to why those two would be starved. Thanks for Both of the diagrams by the way. I missed the one in the manual.

An internal oil leak could be what placed this in motion but here are more thoughts. Although we tend to think that loose bearings go first, they typically get the bulk of the cooling and lubrication because they are loose while tight rods/mains are starved because they don't "leak enough".

More thinking. . .

I don't think that balancing will be an issue. All of the bearing surfaces will be ground to the same diameter, so the weights will stay the same. And you definitely want to turn the crank if the bearings spun to the point that they marred the crank because the surface finish will be bad and won't allow the oil to flow properly, and it'll eliminate the tolerances you need for proper film thickness.

The biggest question to all of this is WHY it did it, otherwise he's potentially looking at a repeat performance some time down the road, depending on the reason. You can treat the symptoms, but until you treat the cause, the symptoms will return.

 

[FinalImpact]

I don't think that balancing will be an issue. All of the bearing surfaces will be ground to the same diameter, so the weights will stay the same. And you definitely want to turn the crank if the bearings spun to the point that they marred the crank because the surface finish will be bad and won't allow the oil to flow properly, and it'll eliminate the tolerances you need for proper film thickness.

The biggest question to all of this is WHY it did it, otherwise he's potentially looking at a repeat performance some time down the road, depending on the reason. You can treat the symptoms, but until you treat the cause, the symptoms will return.

I was saying if you go with replacement parts, then you need to balance. Otherwise, recycle the existing rods to preserve the balancing cost if no other damage can be detected.

I can't imagine the crank journals are fit for use. but I've seen some rough things clean up with a polish and still meet spec. Just trying to be optimistic.

 

[616ah]

I think we are all raising good questions so I'll throw this out:
What are the chances someone over-reved this engine early in life, spun the bearings and it made this far???
QUOTE]

IMHO, I suspect very good chances. Perhapse not spun then, but caused enough damage to increase clearances. A total failure is not always immediate and like you suggest, perhapse over time loose clearances could consume the oil pressure. Earlier I indicated my disapointment that the fz6's do not seem to have a oil presure warning light... That would get your attention if it came on at a hot idle...

IF this is the case then the cause has already been eliminated... (Previous owners right wrist), and restoring all damaged components without omitting anything would be a start.

As to your suggestion of balancing issues - are you sure that it would be affected much? I realize the journals are smaller (lighter) by a few thousandths at most, but therefore the bearings are thicker... I sure hope that a replacement rod for a high performance application would be precision manufactured and matching weights right out of the box, but that could be checked as you never know. I personally also expect the crank is probably finished, but just for discussion sake.

I have more to add as I go, but am out of time for now... Keep your thoughts coming.

 

[TownsendsFJR1300]

I would believe that an out of the box crank and rod from Yamaha (Genuine parts) would not need any further machine work..

If a shop did what you did, they would order genuine NEW PARTS from Yamaha, and replace them. They would not go out hunting machine shops to help install new parts...

 

[616ah]

I'm not suggesting or endorsing machining anything either, quite the opposite actualy. Just batting around the concepts and potential issues since the option was suggested. There is a counter weight for each journal - that says enough for me...

Myself, I am not a big fan of modifying what is a precision engeneered package in the name of saving a buck - especially when it revs to 14000rpm and goes down the highway at 6500RPM. Small amounts of metal off here and there are a big deal when the crankshaft starts to viberate like a tuning fork. Doesn't sound like much, but strength and longevity could be compromized in what is a fairly high power for its size relativly speaking...

Forgive me for excessivly flogging this topic, but the fact that it was suggested as an option provokes discussion...

 

[FinalImpact]

I would believe that an out of the box crank and rod from Yamaha (Genuine parts) would not need any further machine work..

If a shop did what you did, they would order genuine NEW PARTS from Yamaha, and replace them. They would not go out hunting machine shops to help install new parts...

I would think that depends if its a complete assembly or not but I don't know. Maybe Yama'rs process is so good that all factory rods weigh the same and all cranks are balanced to equal amounts. If that is true than new parts are a good solution. From what I see of the Japanese manufacturing processes this could be the way they do it.

We need someone on the inside to answer it tho!

In short, if this is a repair using existing parts it will require different choices and expenses. If its all new parts, crank and 4 rods, it will be another process which still means all clearances needs checked or you risk failure!

Again - too many assumptions with no facts. With that I'll stop as too much is being taken out of context.

 

[TownsendsFJR1300]

I agree with all that's been said and yes, we do need more info.

IF all the journals were taken down for instance .010", the crank would probably need re-balancing, larger bearings of course and no matter what crankshaft goes in there (new or remanfactured) it needs its clearances checked after being torqued down with clearance tape.

My point was the time consumed/hard work has already been done at this point. I personally wouldn't have to do the job again and would just replace the crank/bearings with a genuine Yamaha crank and what ever rods need replacement. I know there's many hours invested in this bike to get to this point. (The money saved already has paid for new parts...)

The motor was designed to run STOCK, to 14k RPM without additional blue printing and balancing.

Just my opinion, of course its up to the bikes owner to make the final decisions....

 

[PhotoAl]

Don't know How Yama does the balancing but has been pointed out it does spin up to 14,000. It is possible that them match sets of rods by weight, normal production would make rods within a small range of weights. If the rods are grouped by weight that would accomplish the same as balancing. I remember reading about that but don't know what engine it was for, might have been a car. Also vaguely recall something about matching the weights of the big end and the small end.

I agree with the comments about getting to the cause of the failure so there is not a repeat.

Great thread with lots of good info.

 

[Wolfman]

As i am just about to pull a TRX850 motor apart to find out what is wrong with it's rattling bottem end, this thread has proved rather informative for me...great thread...

:thumbup:

 

[TownsendsFJR1300]

Don't know How Yama does the balancing but has been pointed out it does spin up to 14,000. It is possible that them match sets of rods by weight, normal production would make rods within a small range of weights. If the rods are grouped by weight that would accomplish the same as balancing. I remember reading about that but don't know what engine it was for, might have been a car. Also vaguely recall something about matching the weights of the big end and the small end.

I agree with the comments about getting to the cause of the failure so there is not a repeat.

Great thread with lots of good info.

Good point but I would think Yamaha would have a slightly different part # for a different(lighter/heavier) rod as they do with any other part (gas tank color has a different part #, etc).

Calling Yamaha tech direct might yield some answers. One dealer that couldn't find a problem with my FJR (corroded electrical connector) called Yamaha direct in California and spoke with their head techies for assistance. I'd bet they could answer all questions re balancing/rod weight, etc...

 

[616ah]

As i am just about to pull a TRX850 motor apart to find out what is wrong with it's rattling bottem end, this thread has proved rather informative for me...great thread...

:thumbup:

Relativly civil too, I might add. I appriciate that. There seems to be experienced persons raising valid points for consideration. What may seem on the surface to be a simple mechanical device becomes increasingly more complex the deeper you get. With respect to that, I've been thinking a bit further than I normally need to most days.

As FinalImpact mentioned, we've all been assuming a fair bit, but the discussion has raised many valid considerations, and missed others for lack of a focused direction. So, yes, patiently waiting for FZling to post more progress and... focus the direction. Lively debate, hope it continues...

 

[FinalImpact]

Relativly civil too, I might add. I appriciate that. There seems to be experienced persons raising valid points for consideration. What may seem on the surface to be a simple mechanical device becomes increasingly more complex the deeper you get. With respect to that, I've been thinking a bit further than I normally need to most days.

As FinalImpact mentioned, we've all been assuming a fair bit, but the discussion has raised many valid considerations, and missed others for lack of a focused direction. So, yes, patiently waiting for FZling to post more progress and... focus the direction. Lively debate, hope it continues...

Build the Fault tree!!
-* Potential reasons for the failure are:
A: it was too tight when manufactured//wrong internals clearances
B: low on oil at some point
C: internal oil leak//it was starved
D: defective oil pump//loose clearances
E: plugged pickup screen
F: Over-rev, sustained over-rev, sustained over-rev while not broken in
G: slow oil return from the head//oil pump starved
H: oil passage feed hole partially blocked
I: crankshaft feed holes plugged or blocked
J: faulty oil pressure relief valve//open to soon
K: wrong oil wt coupled w/cold temp and high RPM when cold
L: bad rod bearing material
M: main bearing clearance was too loose //internal oil leak
N: air leak between pickup screen and oil pump//pump was sucking air
O: debris in the oil

Those come to mind. . .
OP let us know if you need help figuring out why. . .

 

[fZling]

Hey all, sorry for the late reply. It's really hard to find time to work on the bike during weekdays with school and work!

Lots of good info on this thread and really interesting to hear all these different view points.

Overall, I've decided to buy a good 04' crank off ebay with rods included. It's coming off a bike that was crashed, but the crank remained in perfect form (At least that's what he said). I'm replacing all of the main bearings and cam chain as well. Hopefully, depending on when the parts come in, I'll have the bike finished and put back together in 3 weeks.

At first I was going to machine my original crank, but not many places work on bike crankshafts. Plus the bearing dug pretty well into the rod, probably safer to just replace it.

Great points on why this happened on a first place. Am I the first to have this problem with only a baby 6k miles?

I'm going to rule out a couple faults just from what I noticed.

After blowing pressurized air into the crank holes, there was no debris or crap plugging the oil from getting through. The air was flowing easily throughout the crank.

Debris in the oil could perhaps be in. I did change the oil right when I got the bike though. After that the noise really came on, so I doubt it was the oil. (Unless it had already done its damage.)

To be honest, I'm still a little puzzled on why this happened. After showing the bearings to my uncle he thought it could be just badly manufactured.

It's hard to tell if the bike was abused. My guess, probably.... :spank:

This bike was dropped twice, once on each side when I bought it. Didn't think that would really affect anything, would it?

I'll be posting up some more HD pictures asap. Including pictures of all the new parts I'm getting and perhaps a step by step of how my "installation is going".

 

[iSteve]

If the bike was dropped on it side and was still running for several minutes the oil pump could have run dry. Also too much oil can cause air bubbles in the oil and loss of pressure. Or the last owner could have just been a squid and beat the bike before it was broken in.

 

[fZling]

If the bike was dropped on it side and was still running for several minutes the oil pump could have run dry. Also too much oil can cause air bubbles in the oil and loss of pressure. Or the last owner could have just been a squid and beat the bike before it was broken in.

Yeah good point. I have a big feeling it's either one of those scenarios.

 

[TownsendsFJR1300]

Make sure the rod caps remain with each rod as their machined individually. You don't want to mix rod cap ends with the rods (hopefully the seller didn't).

 

[FinalImpact]

So how many of these things can be verified??
I'll make them blue, as I think it can still be determined. . .

Build the Fault tree!!
* Potential reasons for the failure are: *
A: it was too tight when manufactured//wrong internals clearances
B: low on oil at some point
C: internal oil leak//it was starved
D: defective oil pump//loose clearances
E: plugged pickup screen
F: Over-rev, sustained over-rev, sustained over-rev while not broken in
G: slow oil return from the head//oil pump starved//gasket alignment//oil return restricted
H: oil passage feed hole partially blocked
I: crankshaft feed holes plugged or blocked
J: faulty oil pressure relief valve//open to soon
K: wrong oil wt coupled w/cold temp and high RPM when cold
L: bad rod bearing material
M: main bearing clearance was too loose//internal oil leak
N: air leak between pickup screen and oil pump//pump was sucking air
O: debris in the oil
P: assembly error//any of the bearings having the wrong final clearance making an internal oil leak.
Q: crank journals machined incorrectly
R: debris caught in the journals during original assembly
S: cylinder head leak//some port left open//loose clearance
T: bike ran on its side//starved of oil

Those come to mind. . .
OP let us know if you need help figuring out why. . .

 

[616ah]

I doubt being dropped would have any effect. There is a lean angle cut off sensor. Motor shuts down instantly, and if I remember correctly you must cycle the key before it will start again... (Don't ask how I know this... but a snow was bank involved).

+1 to TownsendsFJR1300 comment about the rod caps, generally I think those amy be manufactured by fracturing the big end, so you should find a rough texture on the mating surfaces that will only fit properly back together with the origional pieces. That process fits better than machined surfaces but, yeah, do not mix up... Should be visable if you know what to look for.

FinalImpact's diag tree is well worth deep consideration. You say the the noise got louder right after the oil change? Wonder if the prev owner filled the crankcase with thicker oil to dampen the noise and take up the clearances and by changing it.......