Conclusions

[markjenn]

There was a report that the valve stem seals were changed for 2006 to allow more oil down the valve guide to eliminate the problem. 

From the parts that I have seen and examined the idea of the valve guide/valve stem interface being "too dry" or starved a bit for oil makes a lot of sense.   That fits the failure mode and the "random and rare" evidence of the failure.  

Jestal, from everything I have read about the tickers, the "failures" seem to be predominantly on the #1 cylinder rather than being random on all 4 cylinders. If the valve stem seals are the cause of the failures, is there any logical reason that the valve guides on the #1 cylinder are the most likely to fail?

That's the problem I have with the defective valve seal theory. If each valve seal has a probability of 2% (arbitrary number for calc purposes) that it would cause the valve guide it seals to fail within 10K miles, then here would be the computed odds of different numbers of valve guides failing within a single engine:

0 fail: 85.1%

1 fail: 13.9%

2 fail: 0.1%

3 or more fail: 0.04%

(I'm not sure why these don't add up to exactly 100% - I'm using a binomial probability calculator I found on the net. Regardless, these numbers are representative of how these calculations progress.)

So about 15% of engines might fail, but BY FAR the most common failure would be for a single valve guide to fail and it would be EXTREMELY UNCOMMON for multiple guides to fail.

But the reported data so far is that engines that have had valve guide failure typically fail more than one guide. This strongly suggests that each valve guide is NOT independent of the rest - that within an engine there is some common mechanism that leads to failure that is common to all the valve guides in that engine.

You could explain this by saying that each valve guide is independent, but that some factor in different engines aggravates the failure mode and that tends to cause all the valve guides to fail. Or perhaps the guides are failing independently, but once the head is off, guide failure is over-reported.

I don't know the answer, just pointing out the problem with simple answers.

- Mark

 

[oilyslick]

So, if the part #'s haven't changed, are the techs just replacing seals, guides, etc with the same part #'s hoping to fix the problem? Does anyone that had a ticker know what was specifically replaced to cure the problem? It could be that a repaired ticker could become a ticker again with enough miles. It seems to me that no one really knows what is causing the problem. Perhaps with enough data gathered from the repair of enough tickers, Yamaha engineers will design a permanent fix. We won't really know unless the part numbers quietly change or Yamaha announces a Service Bulletin.

 

[LSUBOY]

Yo Spinner,

Why not reconsider and get the X-tended warranty. Look at it this way.

****It will only cost you 400 bucks as long as you don't live in Florida

****Buying said would give you a 5-Year warranty

****If you sell the bike before the end of the warranty, it could be a selling point

****Having the warranty means you don't have to worry bout nothing but

the clutch and brake pads and anything past that is on YAMAHA

I would not purchase an extended warranty with a car but one of these motorcycles is something else. ABS Brakes, Fuel Injection???? Get tha warranty!

 

[charismaticmegafauna]

oilyslick Posted on Jan 25 2006, 09:10 PM

So, if the part #'s haven't changed, are the techs just replacing seals, guides, etc with the same part #'s hoping to fix the problem?

Not quite: the replacement of valve guides is an operation for which most shops are not qualified. Therefore it's (almost always) jobbed out to an automotive machine shop where the clearances (set w/final reaming of the guide id) may or may not be those specified by Yamaha during factory build in Japan. I'd suggest that, in most cases, the machine shop won't get to Yamaha's exacting standards -- but will err on the side of a somewhat greater clearance approaching those of current accepted automotive standards.

So, you see?, once you have a ticker -- you have a whole new ball-game!

Or, you could take LSUBOY's suggestion and just insure the hell out of everything.....?

 

[Fastfar]

My 03 ticked at 18K and was fixed by Roseville(CA) Yamaha, took 'em 6 weeks and they did not warranty the oil change I insisted on, but the job was done right. They did job the head to a local specialty machine shop that does more tool and die stuff than automotive, and they were slow and cheapskate but at 26K miles and counting, no ticking again.

I bought my FJR used in May 05 with 10K miles and a YES warranty, but I have read that Yamaha will warranty the tick repair regardless. It would make sense if they wanted to avoid a forced recall which would affect the future of sales. It also makes sense that they have R&Ded it to death to make effective tick-changes to 06, if not 05.

But the world may never know what % ticked, and even Yamaha may not know the final tally of tickers for years to come. That should ensure the life of this thread topic in perpetuity... :clap:

 

[S76]

From markjen

"But the reported data so far is that engines that have had valve guide failure typically fail more than one guide. This strongly suggests that each valve guide is NOT independent of the rest - that within an engine there is some common mechanism that leads to failure that is common to all the valve guides in that engine."

Interesting observation.

This would lead one to think that maybe some engines have slightly lower oil presure than others, causing less splash lube to the valve stems. And the fact that they usualy occure on one end of the engine may be due to the fact that that end is furthest from the oil pump. Or some other common denominator.

bob