Knock knock

[fZling]

Re: Knock knock \\ Look inside before you go further!

I'm late in the game but have a few suggestions:
When exactly did the noise start?
Idle:
Under load:
While decelerating:
Coasting - all the time:

With a good load of bad gas and/or a real lean condition from a bad fuel pump, injector issues, plugged fuel pick up, anything making a super lean condition these will make a horrible piston knock which would be prominent during start up, acceleration, under load.

Again - cutting the oil filter open now, will show you the damage. If the filter is clean, tell us about the last load of gas! Poor some out and run in it your lawn mower if you have too. how old is it? How did it run the last time you road it? Was ran out of oil? What are your OC intervals?

If the Oil filter is full of copper and lead looking material, you lost a bearing. If not, I'd inspect the fuel filter and gas.

Tell us everything you know!

The (slight) knock started about 100 miles, after I purchasing the bike. Perhaps I even bought it with the knock and just didn't ride it hard enough to hear anything. The slight knock was between about 4.5-5.5rpm, only during acceleration.

Once the heavy knock hit it happened at idle, didn't bother to try and accelerate after hearing it :jawdrop:

The oil filter was clean, but there were a slight silver goo that came out under connecting rod #3.

The gas was brand new, only used premium as well.

I changed the oil almost right after I bought the bike and according to the sheet he gave me, the oil was changed 600miles prior to me purchasing it.

 

[TownsendsFJR1300]

Sounds like he heard (or had it diagnosed) the noise early and decided to sell it in a hurry before it fully let loose...

I may be wrong but if so, that really sucks...

 

[FinalImpact]

Re: Knock knock \\ Look inside before you go further!

The (slight) knock started about 100 miles, after I purchasing the bike. Perhaps I even bought it with the knock and just didn't ride it hard enough to hear anything. The slight knock was between about 4.5-5.5rpm, only during acceleration.

Once the heavy knock hit it happened at idle, didn't bother to try and accelerate after hearing it :jawdrop:

The oil filter was clean, but there were a slight silver goo that came out under connecting rod #3.

The gas was brand new, only used premium as well.

I changed the oil almost right after I bought the bike and according to the sheet he gave me, the oil was changed 600miles prior to me purchasing it.

Sorry to see this. . . Glad you're keeping a good attitude!

So in the pic up there, you're saying there is a film on metal dust slung around the #3 journal? I can't tell from the photo but I think thats what you meant.

Unfortunately I have a less than pleasant sound from my bike but its hard to tell what it is. Its used and I'm the second owner on it w/41XX miles.

 

[FinalImpact]

Sounds like he heard (or had it diagnosed) the noise early and decided to sell it in a hurry before it fully let loose... :thumbdown: :thumbdown: :spank: :thumbdown: :thumbdown:

I may be wrong but if so, that really sucks...

Very True - Loser!

 

[Bigchess]

@fzling

Hey I've been following your post and I was looking at how the main bearing goes around the crank. It looks like you may be able to access the main bearing by just taking off the oil pan. I seen that you have already removed that and it looks like the bearing might be accessible from there. I have yet to have to take apart my fz6 so I don't know much about the engine or the way it is set up but hopefully that helps. Below is an image of the bearing that wraps around the bottom of the crank. Keep us informed on whats happening. :rockon:

 

[TownsendsFJR1300]

@fzling

Hey I've been following your post and I was looking at how the main bearing goes around the crank. It looks like you may be able to access the main bearing by just taking off the oil pan. I seen that you have already removed that and it looks like the bearing might be accessible from there. I have yet to have to take apart my fz6 so I don't know much about the engine or the way it is set up but hopefully that helps. Below is an image of the bearing that wraps around the bottom of the crank. Keep us informed on whats happening. :rockon:

The bearing is the same as most automotive lower end bearings with a tab to keep it from spinning in the connecting rod. Generally, once it starts knocking it tears up the crankshaft (checking with a mic with tell if its out of round yet) and the big rod end gets elongated, (again, you can check it with a mic but the end cap needs to be on and torqued down for an accurate reading). Machining is due at that point but I don't know if oversize lower rod bearings are available should the crank need to get cut down..

Looking on Babbits for parts, seems there are oversize bearings available, the crankshaft itself about $325, the connecting rod about $75 each and the bearings about $5.80 (including oversize).

 

[Bigchess]

The bearing is the same as most automotive lower end bearings with a tab to keep it from spinning in the connecting rod. Generally, once it starts knocking it tears up the crankshaft (checking with a mic with tell if its out of round yet) and the big rod end gets elongated, (again, you can check it with a mic but the end cap needs to be on and torqued down for an accurate reading). Machining is due at that point but I don't know if oversize lower rod bearings are available should the crank need to get cut down..

Looking on Babbits for parts, seems there are oversize bearings available, the crankshaft itself about $325, the connecting rod about $75 each and the bearings about $5.80 (including oversize).

Thanks for adding in this information Towns!!! I never have had to do this myself so would not have known :Flash:

 

[04fizzer]

The bearing is the same as most automotive lower end bearings with a tab to keep it from spinning in the connecting rod. Generally, once it starts knocking it tears up the crankshaft (checking with a mic with tell if its out of round yet) and the big rod end gets elongated, (again, you can check it with a mic but the end cap needs to be on and torqued down for an accurate reading). Machining is due at that point but I don't know if oversize lower rod bearings are available should the crank need to get cut down..

Looking on Babbits for parts, seems there are oversize bearings available, the crankshaft itself about $325, the connecting rod about $75 each and the bearings about $5.80 (including oversize).

It's possible that turning the crank may be all that's needed. I had to have the crank ground on my boat motor (3.7L I4 Mercruiser), and it ran about $150, I believe. Grinding a mike crankshaft will probably run about the same. If he's lucky, the only thing that got damaged will be the crank, so a grind and oversized bearings should be enough *hopefully*.

 

[TownsendsFJR1300]

It's possible that turning the crank may be all that's needed. I had to have the crank ground on my boat motor (3.7L I4 Mercruiser), and it ran about $150, I believe. Grinding a mike crankshaft will probably run about the same. If he's lucky, the only thing that got damaged will be the crank, so a grind and oversized bearings should be enough *hopefully*.

If he caught it early enough, yepper!

 

[Silver05]

just shows how knowledgeable some of our members are. I work on my YZ250F a bit, but this would require an entirely different level of knowledge... and confidence.

I'm glad the OP is making progress, and I look forward to reading the success story soon.

 

[04fizzer]

If he caught it early enough, yepper!

That's assuming, he didn't spin the bearing, then both could be shot, and that'll take a lot more work. It's not repairable, just going to take more work: removal of the head, pistons, and crank, and possible replacement of rods.

BUT, that's all speculation without being able to see it and investigate more.

 

[TownsendsFJR1300]

That's assuming, he didn't spin the bearing, then both could be shot, and that'll take a lot more work. It's not repairable, just going to take more work: removal of the head, pistons, and crank, and possible replacement of rods.

BUT, that's all speculation without being able to see it and investigate more.

I agree and that's what I posted. If its spun, I quoted some prices of what would need replacing if it couldn't be machined.. The crank can be machined, that's why they make oversized bearings. Hopefully it didn't spin the bearing and just the soft bearing is toast..

 

[616ah]

But we're all still guessing, so here's more stating what seems obvious to me to further speculation.

To get the described magnitude of knock from a rod, there is little chance of doing a reliable repair with less than a rod and crank service/repl. That means the head comes off to get the piston(s) out. (head gasket, strech bolts, ring compressor, more effort, etc). If I ever have a rod bearing fail, there is no way that I would ever reuse the rod (unless it is an old lawnmower) for fear that it could be fractured or very slightly bent. Also, consider the oil pump, because those metal bits probably went through it, scraping all the way.

The question of "why did this happen" still deserves deep consideration, as it may direct you deeper. Many visuals of what could cause this, unfortunatly all are bad.

Thanks for keeping us posted, lots of good info here.

 

[TownsendsFJR1300]

The question of "why did this happen" still deserves deep consideration, as it may direct you deeper. Many visuals of what could cause this, unfortunatly all are bad.

Thanks for keeping us posted, lots of good info here.[/QUOTE]


+1 on this....

 

[fZling]

Wow, lot's of replies. Thanks for the input everyone!

Found that the main crankshaft bearings were in excellent condition. The #4 rod bearing had completely spun. The #2 rod bearing was beginning to spin. Rod bearings on 1 & 3 had some wear. Any ideas on why the connecting bearings were toast, while the main bearings were in perfect condition?

Here's how the bearings are looking,

So in a couple weekends, I've gone from...

To...

 

[Boneman]

^^^wow....you Sir are a braver man than I will ever be!!!! :thumbup:

 

[TownsendsFJR1300]

Over revving, lack of adequete frequent oil changes or crap in oiling system would contribute to the rods bearings going bad.

The main bearings simply cradle the crankshaft, the rod bearings take the beating of the piston changing direction on every stroke (taking the pounding.)

Blowing air thru the crankshaft oil inlets is a must and see if anything comes out. I believe the oil goes from the mains thru the crank to the rod bearings.

Excellent job BTW. With the head off, seems you can get by with a new rod, bearings and either cut the crank or just replace it depending on the condition of it.

 

[616ah]

I was expecting worse, although in reality there is nearly as much damage as if the bearings were totally shreaded. What do you suspect is the root cause? Looking at the cam bearing surfaces might give a hint to an oil starvation issue, but I doubt you'll find much. Other things that cross my mind: transmission input bearings could be worth a look. I'm leaning toward excessive sustained RPM melt down.

Best of luck if decide to rebuild - might be worth a go once all is figured out. Looks like you've got a good place to work at it. Always creeps me out a bit building an engine that has had loose metal bits circulating, and a possible history of abuse, but realistically if you're carefull and take the time to make sure everything is totally cleaned out, inspected, torqued, replace torque to yield fastners, and check clearances, you should achieve a reliable repair. Its a lot of time invested to do it right, but its a real feeling of accomplishment when you get it done and done right. If you have the time and patience and the parts don't cost excessive - go for it!

Thanks for sharing your disaster so far - please keep us posted!

 

[FinalImpact]

Ouch! And sorry Again! Great Attitude and Good Job!

IME, spun bearings happen for 1 of 2 reasons. It was too tight, or there was no oil. It has enough miles on it that if it were too tight that would have came to light much earlier. So I'd guess that brings you to why did it not have enough oil?

I tried to find an oiling diagram to see how the system is fed but no luck. There are 5 mains and its likely 4 of the mains feed for of the rods. 2 & 4 and 1 & 3 are effectively pairs so I'd be looking close at the crank feeds from the bad rods.

Question: Are the bad rods discolored? Do they look darker or have bands of colors on the caps when compared to the OK rods?

Because you can see the copper/babbit material worn from the bearings, that likely means this was underway for a while and the clearances were increasing (GUESS).

It could be that once you mic the ID of the rods and remove any transfer material, they could mic out within spec. In this case the bearing gave its life and protected the rod which is what its supposed to do. Once you have them out, get them mic'd and see if they are in spec.

Same is true of the crank. Remove any transfer material and mic them.

Because its used you just don't know what it saw in its previously life. Was it a plugged filter, sustained high-speed operation while low on oil, bad oil, Redline operation, defective oil pump, oil leaks somewhere else (engine show any signs of being apart before), defective pressure relief spring, a check ball or check valve stuck or missing?

So many things to consider. Take lots of good close high res pictures and I'll give you my 2 cents if you want it.

 

[616ah]

View attachment 34820

Here I go thinking again...

No attack intended, just some further thinking here. As near as I see the only thing that #2 and #4 have in common is that they are on the same crankshaft in the same motor. Totally seperate crankshaft drillings for the oil supply. Since the main bearings are all feed by the same oil passage, and are looking good according to the OP, me thinks they had sufficient oil to prevent burn out - perhapse the weakest link when operated beond the limits of sanity would be the oil supply to the rod bearings? Thoughts?

Also, If a bearing shell is exposed to enough force to spin inside a tight fit rod big end with no lube supply, regardless of measurements, heat marks, etc, would you even consider re-using it when the specs are published to 4 decimal places?