Engine knocking - connecting rod bearing?

[cosmohawk]

Hey there...and yes, I'm a newbie to this site...first post.

If it's any consolation, I have been reading many posts regarding this topic...but nothing seems to fit my problem...here's the situation.

A guy called me up the other night because he heard that I work on old bikes in my spare time, and he did not want to take the bike to our local Yamaha dealership for problem diagnosis ($$$).  He dropped the Vision off to me the other night, and explained to me what had happened to him while riding.

Basically he was driving the bike (somewhat hard), and then started noticing a slight knocking noise from the bike...started losing power and the engine oil light came on.  He pulled over and shut the bike off immediately.

The engine starts and idles perfectly fine without any knocking or ticking noises now, but if you give it some throttle (and bring the revs up to around 2500 - 300rpm?) it starts making a knocking noise, and the gets progressively worse as the revs increase from there.

Now I've heard this sound before on a EX500 twin that had a bad connecting rod bearing (due to oil starvation / lack of oil / sludge)...so immediately I thought "bad rod bearing".  Then I came here and started searching for "engine knock", and have since perused many a thread about starter clutch / flywheel bolt fixes and the like...but have not yet found any topic regarding an engine knock with increasing revs.

I'm almost 90% sure it's a bad rod bearing from what I've heard...can anyone confirm???

This is my first experience with a Vision.

Thanks, ;)
Mark
New Brunswick, Canada

[Superfly]

Hey Mark, and welcome!

I had a Similar problem happen to me on a motorcycle run.  The experience I had is that the bike started loosing power, then, it felt like it was running on one cylinder, the oil light was flickering on and off, and I really had to fight to keep the bike running.  I was able to get back to the hotel I was staying at, but after a few minutes of tinkering, the berring rolled.  It happens on these bikes sometimes, but that is worse case scenerio.

[kwells]

Well it sounds like you said the 'knock' got progressively worse with RPMs.  I assume at no point does the sound disappear when you rev it up?  When the starter clutch bolts begin backing out they will 'knock' against the cover until it is revved up.  Definitely make sure BOTH cylinders are firing but you are probably on track with the slung bearing diagnosis.

[haunter]

sounds like a bad bearing, but heed the starter clutch warning!

[cosmohawk]

Yes, the "knocking" gets progressively worse as revs increase above 2000 - 2500 rpm.  Both cylinders are firing, and like I said...the bike sounds like it's running just purrrrrfect from idle.  The oil light is not on anymore...it only happened I gather...under hard riding, when the knock first appeared.

I think I'm up in the 99% range now...connecting rod bearing...

I'll check the starter clutch / flywheel assembly anyways...man, that would be great if that was the fix.

Sounds to me like he's going to part the bike out if the motor needs serious money / time invested.  Too bad though...I'm a firm believer in ressurecting old bikes, regardless of cost / time...lord knows I've done it a few times already. :P

[kwells]

would probably be easier to just put in another motor...Im sure they could be had for well under $200.00.  The trick would be finding one nearby so it doesn't have to be shipped.

[Night Vision]

I'll check the starter clutch / flywheel assembly anyways...man, that would be great if that was the fix.

I assume you checked the oil level....
check to make sure the balancer gear nut is tight and that 46mm nut on the crank behind the starter clutch is tight also... both will loosen up over time and get noisy.....

[reckon]

Yes, the "knocking" gets progressively worse as revs increase above 2000 - 2500 rpm.  Both cylinders are firing, and like I said...the bike sounds like it's running just purrrrrfect from idle.  The oil light is not on anymore...it only happened I gather...under hard riding, when the knock first appeared.

I think I'm up in the 99% range now...connecting rod bearing...

I'll check the starter clutch / flywheel assembly anyways...man, that would be great if that was the fix.

Sounds to me like he's going to part the bike out if the motor needs serious money / time invested.  Too bad though...I'm a firm believer in ressurecting old bikes, regardless of cost / time...lord knows I've done it a few times already. :P

check the starter first (it's an easy rule out),...but I'm with you, sounds like he spun a rod bearing

[cosmohawk]

Thanks for the advice and suggestions for a fix...

You guys are really helpful, and prompt with your replies...even if it's the 100th time you had to tell a newb what to look for or how to fix.

Kudos!  ;D

[Coil Coyle]

Pull the oil filter. There will be copper and Babbitt flakes if it is the bearings.

:-\
Coil

[reckon]

Yes, the "knocking" gets progressively worse as revs increase above 2000 - 2500 rpm.  Both cylinders are firing, and like I said...the bike sounds like it's running just purrrrrfect from idle.  The oil light is not on anymore...it only happened I gather...under hard riding, when the knock first appeared.

I think I'm up in the 99% range now...connecting rod bearing...

I'll check the starter clutch / flywheel assembly anyways...man, that would be great if that was the fix.

Sounds to me like he's going to part the bike out if the motor needs serious money / time invested.  Too bad though...I'm a firm believer in ressurecting old bikes, regardless of cost / time...lord knows I've done it a few times already. :P

check the starter first (it's an easy rule out),...but I'm with you, sounds like he spun a rod bearing

another thought,...if it is the rod bearing, why not just get another motor for it?  plenty of visions  with less than 20K on them all over the place: salvage yards, peoples yards, IN the lawn (if ya mow yer lawn, and find a couple of yamaha visions, you might be an ROV'r :D ),...you could probably pick up a parts bike for $200-$300 and swap the motors, and keep all the tasty bits (tci, RR, bars, pegs, etc.

vision motors are one of the easier motors to R&R (remove and replace) in motorcycledom

[QBS]

I consider the appearance of oil pressure light while the engine is running to be the kiss of death for the V lower end.  Major lower end damage has occurred.  Someone obviously didn't change their oil and filter very often.  V engines are tough.  Their lower ends (if properly cared for) are definitely not a problem area.

[cosmohawk]

So...should I even bother tearing the motor apart to find out the ACTUAL problem?

I thought about tearing the starter clutch apart to check for loose bolts, but I don't have the right flywheel puller...and I'd probably choose not to bother with the whole damn thing if he's just gunna decide to part the bike out after all is said and done.

I think it's a given that the crank / rod is toast...

BTW...when I drained the oil...there was just over 3 litres in the motor (calls for 2.4 - 2400ml on the case).  Would this have had anything to do with the noise?  I can't believe that it would self-destruct with more than enough clean oil pumping through the system...but maybe? too much oil pressure?

I still have yet to check the filter for metal bits...will do that this afternoon.

And there is a used motor on Ebay right now out of California...for around $100 plus shipping.

[QBS]

For the last 23 years and 88k miles, I've always put 3 qrts. of oil in the crankcase with a filter change.  The owners manual calls for 2.9.  My rods haven't complained yet.

[Night Vision]

how much does it cost to pull the the oil filter? .... about $0 USD

how much does it cost for a flywheel puller? ...... about $20 USD

how much does it cost to ship an engine from CA to NB? .... I don't know :P

how much will the folks in ON pay for a parts bike? ...... ask 'em

[cosmohawk]

Okay...no problem...I get the idea...

This is the first Vision I've basically ever seen or worked on...but after pulling the oil filter, I have to ask...

What's all this shiny stuff???  :D :P





Thanks for the help...next time I see him, I'll be "bearing" some bad news... :D :-\

[kwells]

That's YamaGlitter.  It is the expensive oil additive that Yamaha charges $19/qt. at the stealership.  Most of us have stopped using that and now just use plain old oil.  There are some aftermarket additives similar in nature such as DinoGrit and Scuff50 but their long term statistics are less known since there were even more expensive. 

[Ron_McCoy]

At least Scuff50 comes with a money-back guarantee.

[jefferson]

I thought I might chime in on the over full on oil issue. If the bike had too much oil in it and he was running it hard there is a good chance that he aerated the oil, and aerated oil won't keep the bearing from contacting the crank pin. You are going to get worse fuel mileage in the least and motor damage at worst when you run a high oil level. I have always heard and abided by the adage that too little is better than too much when it comes to oil levels.
The only advantage to a high level is when you are prone to doing those mile long wheelies. That way it hopefully keeps some of the oil near the pickup. I have never had a wheelie problem with the V although I am really not very good at them anyway.

Jeff