Connecting Rod Failures

[David Gaul]

Hello. I am new to this forum. I am about to purchase a 1997 V-Max with 44k miles from an out-of-state seller for $3k, but I just heard about potential connecting rod failures. How common are connecting rod failures in a V-Max? The original owner says he never abused this bike, and took good care of it. I am unable to personally see the bike or hear it run before this purchase. Would you proceed with this purchase? Can I drop the oil pan and inspect the lower end without removing the engine from the frame?

Thank you.

 

[MaxMidnight]

I have been on this site since 2007 and don't recall any con rod failures (I assume you mean snapped?)
Perhaps you could indicate where you heard this 'rumour'?
There are the very rare big end failures (and I mean very rare) and I suspect mo more than any other machine.

You would need to remove the exhaust before you could remove the sump but not sure what you would expect to see by a visual inspection. (Thinks: perhaps we have a super hero here who has X-ray vision??? ).

Like any bike it has a few foibles (see attached) but if well looked after and not abused are pretty much bullet proof. If the seller is true to his word he should be able to provide invoices to demonstrate what has been spent on the bike during his ownership.

Only you can decide if you want to buy it and it is only when you get it home will you discover if the vendor as honest as the day is long or as bent as a nine bob note.

 

[caseyjones955]

I've scarcely read about low end engine failures either. I did have an XVZ (same-ish V4 engine) and I was sure I had a faint rod knock, at hot idle it was faintly detectable and had that alarming big end resonance. After walking around the bike in circules with a tech stethascope I isolated it to a clutch basket and noticed it waned with clutch actuation. Actual hard engine failures do indeed seem scarce but signt unseen for a 30+ year old bike is likely to come with some maintainance related expenses.

You have no location, if the bike is in the Black Hills area/Rapid City I'm willing to have a peek at it for you.

 

[Maxcaddy]

Conrod failures in terms of the small end are not rare, and there are instances of it happening with an associated 'knock' usually on No 3 cylinder.

There is/was a conrod modification to address small end issues advised by Exactrep (UK).

 

[David Gaul]

I have been on this site since 2007 and don't recall any con rod failures (I assume you mean snapped?)
Perhaps you could indicate where you heard this 'rumour'?
There are the very rare big end failures (and I mean very rare) and I suspect mo more than any other machine.

You would need to remove the exhaust before you could remove the sump but not sure what you would expect to see by a visual inspection. (Thinks: perhaps we have a super hero here who has X-ray vision??? ).

Like any bike it has a few foibles (see attached) but if well looked after and not abused are pretty much bullet proof. If the seller is true to his word he should be able to provide invoices to demonstrate what has been spent on the bike during his ownership.

Only you can decide if you want to buy it and it is only when you get it home will you discover if the vendor as honest as the day is long or as bent as a nine bob note.

Hello Max, thank you very much for your reply.

There are multiple threads about connecting rod failures on this forum. My friend, who owns his own motorcycle repair shop here in San Diego California (DWS Powersports) and has been employed as a mechanic for over forty years, informed me he rebuilt two V-Max bikes with broken connecting rods back in the early nineties.

A visual inspection of a lower end can tell a lot. Simply holding the connecting rod in your hand and checking it for free play on the crankshaft will tell you if the bearing has excessive play. I assumed that it was the large end bearing that was failing, but it appears that the common failure may in fact be the small end rod bearing, that would be impossible to evaluate by removing the oil pan. Additionally, I have read that there may be an issue with a defective o-ring attaching to the oil pump, that I thought could be examined by dropping the oil pan.

I thank you again for responding to my questions, and for supplying the attachment. I have discovered that this forum has a great bunch of knowledgeable and friendly people, and I will most likely be visiting again on a routine basis.

 

[David Gaul]

I've scarcely read about low end engine failures either. I did have an XVZ (same-ish V4 engine) and I was sure I had a faint rod knock, at hot idle it was faintly detectable and had that alarming big end resonance. After walking around the bike in circules with a tech stethascope I isolated it to a clutch basket and noticed it waned with clutch actuation. Actual hard engine failures do indeed seem scarce but signt unseen for a 30+ year old bike is likely to come with some maintainance related expenses.

You have no location, if the bike is in the Black Hills area/Rapid City I'm willing to have a peek at it for you.

Hello CaseyJones. Thank you so much for your reply, and especially for your offer to inspect this bike. Unfortunately the bike in in Webster, New York (upstate), and I am in Murrieta California (just north of San Diego, where I lived the last 33 years). I have asked my brother, who lives about 35 miles away from the seller, to inspect this bike, and to complete the transaction for me. Unfortunately, my brother doesn't really know much about motorcycles, but he should be able to detect a rod knock if one is present.

Thanks again for your kind offer to help.

 

[David Gaul]

Conrod failures in terms of the small end are not rare, and there are instances of it happening with an associated 'knock' usually on No 3 cylinder.

There is/was a conrod modification to address small end issues advised by Exactrep (UK).

Thank you very much for your reply Maxcaddy. My friend, who is a professional mechanic and owns his own shop (DWS Powersports in San Diego Ca), informed me that he personally repaired two V-Maxs with blown connecting rods in the early nineties. This got me worried about my pending purchase, and I started to research the topic of blown connecting rods in V-Max motorcycles. I found a few threads on this forum that discussed this topic. A forum member named Sean, who sounds extremely knowledgeable, stated "I've probably got a stack of 50 sets of shit cases sitting in the scrap pile". He didn't state that all of these damaged cases were the result of connecting rod failures, but I got the impression that many of them were.

I am trying to determine if failed connecting rods in the V-Max is a common issue, and it sounds like it is a more common occurrence in this bike than most other bikes. Is this because of a manufacturing or design defect? Does anyone remember the camshaft (or crankshaft?) failures in the Honda VFR500, back in the early eighties? It would be great to understand if this is a common issue or if this is a rare occurrence. I would also like to know if the root cause of the failure has ever been identified. I read a thread on this forum where a member mentioned something about an o-ring that is associated with the oil pump. Does this failure only happen to bikes that are poorly maintained, or abused (drag raced)? Does anyone know if there was ever a factory recall by Yamaha? Does anyone know if there are any know "fixes" that can be performed to prevent this from happening? ( I see your reference above, thank you, I will try to find this).

Thank you again for your response.

 

[Fire-medic]

Sean Morley and his Pile of Shame engine cases are there probably because of damaged thrust bearing surfaces for the lateral movement of the crankshaft. Excess play in the wrist pin, excess play in the big end of the connecting rod or excess play in the crankshaft journals pretty much covers the reciprocating motion and places where damage could occur. Excess lateral movement of the connecting rods and/or crankshaft can damage the thrust bearing surface on the cases. While those potentially could be fixed it's usually cheaper to get another set of undamaged cases.

The O-ring on the oil pump can become displaced, it is commonly called popped, and Sean Morley offers a kit to fix this as well as to provide additional oil capacity. An oil O- ring from a KLR 650 single Kawasaki is one fix. If you search for "popped o-ring" on the Forum you can see examples of this having occurred to stock VMAX oil pumps.

Call Larry Fitzgerald at LCR Performance in Rochester New York if you're looking for a qualified individual to evaluate a potential motorcycle purchase from someone in Webster New York.

560 Avis Street
Rochester, New York 14615
585 458 8185

Larry is who you want to look at a VMax bike in Western New York. I suspect Larry may already be knowledgeable about this bike assuming this bike has come through his shop because he is the go-to person in Western New York for stock and modified Yamaha VMAXes. I have been to his shop and he will be able to give you an accurate evaluation of the condition of the bike as far as you are willing to go in the inspection depth of process.

 

[MaxMidnight]

There are multiple threads about connecting rod failures on this forum. My friend, who owns his own motorcycle repair shop here in San Diego California (DWS Powersports) and has been employed as a mechanic for over forty years, informed me he rebuilt two V-Max bikes with broken connecting rods back in the early nineties.

I'll stick my neck out here and say that con rod failure is NOT a generic design fault with the Max. There will inevitably be failures but this can be down to various factors including poor or non existent maintenance or abuse e.g over revving by the user. As this is a Forum for V Maxii all manner of faults are mentioned so it is, perhaps inevitable, that even rare occurrences will feature. How they compared with other bikes I know not as I'm not aware of any collated statistics on the issue.

A visual inspection of a lower end can tell a lot. Simply holding the connecting rod in your hand and checking it for free play on the crankshaft will tell you if the bearing has excessive play. I assumed that it was the large end bearing that was failing, but it appears that the common failure may in fact be the small end rod bearing, that would be impossible to evaluate by removing the oil pan.

The maximum wear limit on the big end is is 0.0035". How much over that would it have to be before it was evident by trying to move the rod?
Once again, I'll stick my neck out here and whilst there is the occasional report of noisy small ends (as opposed to failure i.e. breaking) it is NOT common.

Additionally, I have read that there may be an issue with a defective o-ring attaching to the oil pump, that I thought could be examined by dropping the oil pan.

The 'orange O ring' saga has been going on since I first joined this and other forums and has (IMO) probably generated more paranoia among owners than any other issue. What percentages of bikes are affected I know not but as Yamaha didn't feel the need to issue a recall then it is likely that any problems this could cause (engines failure, press and owner publicity) was not felt to be sufficient to require action (unlike the Honda camshafts). It wasn't until the early 2000's that the pick-up was modified (over 25 years since the bike was unveiled) so they hardly felt it was an issue. If it had been then they would have identified this from warranty costs, parts usage and customer feedback. There have been and in all likelihood still are bikes that have been running for many years with a displaced O ring without any issue.
Page 5-3 of the owners manual states 'Never accelerate hard with a cold engine'. IMO displacement occurs when owners ignore this and before the oil is up to temperature. When cold oil pressure is around 60 psi on fast tick over but will drop to around 3 or 4p.s.i. when hot.
Depending on your level of paranoia there are several things you can do. Already mentioned is the Kawasaki oval O ring (part #92055-1147), fit a so called engine saver bracket that limits how far the pick-up tube can move or fit the later pick up tube.

I thank you again for responding to my questions, and for supplying the attachment. I have discovered that this forum has a great bunch of knowledgeable and friendly people, and I will most likely be visiting again on a routine basis.

If I was considering a Max one of the last things I would be concerned about is internal issues with the engine provided it has been treated with respect and serviced regularly. And if that has been done then higher mileage bikes are not a problem.
That said the adage 'buyer beware' still applies.

I wouldn't buy a bike sight unseen unless it had been checked over by someone I trusted. Even then I would prefer to meet the owner to assess not only if what was claimed checks out but also if the body language fit the comments.

I hope you get a Max and we are always happy to offer our two penneth.

 

[Robby Tweak]

I'll stick my neck out here and say that con rod failure is NOT a generic design fault with the Max. There will inevitably be failures but this can be down to various factors including poor or non existent maintenance or abuse e.g over revving by the user. As this is a Forum for V Maxii all manner of faults are mentioned so it is, perhaps inevitable, that even rare occurrences will feature. How they compared with other bikes I know not as I'm not aware of any collated statistics on the issue.

The maximum wear limit on the big end is is 0.0035". How much over that would it have to be before it was evident by trying to move the rod?
Once again, I'll stick my neck out here and whilst there is the occasional report of noisy small ends (as opposed to failure i.e. breaking) it is NOT common.

The 'orange O ring' saga has been going on since I first joined this and other forums and has (IMO) probably generated more paranoia among owners than any other issue. What percentages of bikes are affected I know not but as Yamaha didn't feel the need to issue a recall then it is likely that any problems this could cause (engines failure, press and owner publicity) was not felt to be sufficient to require action (unlike the Honda camshafts). It wasn't until the early 2000's that the pick-up was modified (over 25 years since the bike was unveiled) so they hardly felt it was an issue. If it had been then they would have identified this from warranty costs, parts usage and customer feedback. There have been and in all likelihood still are bikes that have been running for many years with a displaced O ring without any issue.
Page 5-3 of the owners manual states 'Never accelerate hard with a cold engine'. IMO displacement occurs when owners ignore this and before the oil is up to temperature. When cold oil pressure is around 60 psi on fast tick over but will drop to around 3 or 4p.s.i. when hot.
Depending on your level of paranoia there are several things you can do. Already mentioned is the Kawasaki oval O ring (part #92055-1147), fit a so called engine saver bracket that limits how far the pick-up tube can move or fit the later pick up tube.

If I was considering a Max one of the last things I would be concerned about is internal issues with the engine provided it has been treated with respect and serviced regularly. And if that has been done then higher mileage bikes are not a problem.
That said the adage 'buyer beware' still applies.

I wouldn't buy a bike sight unseen unless it had been checked over by someone I trusted. Even then I would prefer to meet the owner to assess not only if what was claimed checks out but also if the body language fit the comments.

I hope you get a Max and we are always happy to offer our two penneth.

I could not agree more with your comment. It is how you handle your bike and the interval of the maintenance. You can google all kind of motor brands and there will be always things that can cause problems. If you want to rule out things, buy a new motorcycle. I own a 1996 Vmax with a 1999 engine because the former owner was a cheap liar and did not handle the Vmax very well. So i replaced the engine with one from Schwabenmax Lesson learned.
Greetings