There have been numerous posts and questions over the years of this forum’s existence concerning noisy cam chains, due to the OEM cam chain tensioner not being up to the task.
There have also been documented disastrous results from cam chain tensioner failures, resulting in destruction of the valve train and expensive follow-up repairs. Incidentally, all four documented cases of catastrophic cam chain tensioner failures involved 2004 model motors, however there easily might be other, forum-undocumented failures resulting in engine damage in other model years.
A cursory examination of past posts involving cam chain noise emanating from the right side of the motor indicates the original OEM cam chain tensioner (hereafter referred to as CCT) has a finite life, although Yamaha doesn’t suggest a maintenance or replacement schedule for the original part.
However, there seems to be an indication that Yamaha is aware of a problem, considering a recent design and part number change for the OEM unit with forum members who have replaced their OEM unit with the updated model indicating the new replacement part incorporates a longer shaft in the adjustment mechanism, providing more extension of the adjusting shaft at less spring deflection, effectively improving the capabilities of the design, and possibly providing a longer MTBF (mean time between failure) for the OEM replacement .
From my investigations, reported cam chain noise has come as early as 7,000 miles, or as late as over 110,000 miles, so there doesn’t seem to be a pattern for early failure in the OEM CCT. However, after reading many of the threads involving cam chain noise and CCT replacements, it could be deduced that many of the failure issues have immediately, or at a reasonably short time, followed a valve adjustment, where the CCT had been retracted for cam removal.
What follows is a list of random forum posts involving cam chain noise:
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Indications from “autopsied” CCTs seem to demonstrate that some OEM units displayed much less tension in the spring than others do, hinting that assembly of the OEM unit may be a factor in short-life failures, as the OEM unit can be assembled with differing levels of spring tension.
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The purpose of this thread is to determine, by survey, if you have experienced cam chain noise and what action was taken to eliminate the noise. With consolidated information we might be able to provide Yamaha positive feedback or maybe push for a recall.[/SIZE]
If you wish to participate in the survey, please indicate
A – the model year of your FJR
B – the number of miles on your FJR when the cam chain noise became apparent
C – what action did you take, i.e., replace the CCT yourself, have the dealer do the work, ignore the noise, etc., and at what mileage
D – did replacing the CCT eliminate the problem, i.e., the chain noise
E – was the problem diagnosed by a dealer and if so, dealer name and specifics
F – were there any problems related to the CCT failure, i.e., cylinder head damage/engine replacement
G – if the repair/replacement was performed by a dealer, how many days
H – paid for by Yamaha or not/under conventional warranty or Y.E.S
I – have you replaced your CCT more than once, including how many times, mileage at replacements
J – did the chain noise begin randomly, or did it begin following valve adjustment, where the CCT needed to be de-tensioned to facilitate cam removal
K - if you are needing to change your CCT are you confident Yamaha's redesign is sufficient or are you considering replacement with a manual aftermarket design
This survey is strictly informative. Please, let’s keep it that way.
To kick things off, I'll use my own experience to fill in the survey:
A - 2004
B - 39,000 miles when the noise began, 46,000 miles when the CCT failed completely, destroying my cylinder head
C - I (unfortunately) ignored the noise until it was too late
D - Not applicable in my situation. Replacement motor was installed after "B"
E - The dealer, Sky Powersports, Lakeland, Florida, told me "they all sound like that"
F - Motor replacement due to destroyed valve train
G - Not applicable. Motor replacement done by myself
H - No Y.E.S. Replacement motor funded by forum generosity
I - No replacement in original motor. OEM replaced with manual aftermarket model in replacement motor
J - Chain noise began randomly. Not associated with valve adjustment or cam removal
K - I wouldn't trust my FJR with the OEM unit, re-designed or not. Replaced with manual unit from APE
If you participate, please snip and respond with survey info only.
Thanks,
‘Howie
Admin Note: After building this thread with great diligence from the thread starter and forum contribution, this issue has been assigned for forum use FJRF008: Cam Chain Tensioner Failures. Although the issue does not have any known formal Yamaha Technical Bulletin, feel free to use this term and reference this thread when working with Yamaha dealers or Yamaha Corporate with warranty coverage. Perhaps they will too acknowledge the issue formally and assign a technical bulletin.