Downshift Problem and Solution

[ejy712]

I've been having a downshift problem for a while. My S10 upshifts fine. But downshifting was hit or miss, sometimes requiring multiple taps on the shift pedal. I read in this forum that cleaning and greasing the shift pedal pivot was the answer. I tried this and it worked - for a while.

On a recent 2200 mile trip the problem got a lot worse. I got to start in third several times because the beast just wouldn't downshift.

About 2/3rds through the trip I stopped at Sandhill Yamaha in Pinehurst North Carolina. They very kindly took me in on a moments notice. They have a remarkable mechanic/technician who diagnosed and fixed the problem. Oddly they have not sold an S10. Mine was the second one they had seen. The first had a problem with the OEM luggage locks which they fixed.

The problem turned out to be a broken "Shift shaft spring". The pictures below are self explanatory:
[smg id=1306]
[smg id=1307]
[smg id=1305]

If you look closely you will see where the crack is propagating past the break on the larger remainder of the spring. This looks like failure started in shear which weakened the spring causing it to be less effective. Over time the crack progressed far enough to cause catastrophic failure. Fortunately the spring was still together when it was removed. It finally fractured when the mechanic stressed it lightly to demonstrate the problem.

Downshifting is now back to normal - one tap in the shift pedal is always one gear down.

I had between 28,000 and 29,000 miles on the S10 when the fix was made.

I am not discouraged by this. Anything made by man can fail. The S10 is by far the best motorcycle I have ever owned...

 

[Duconce]

Was just wondering if you ride your bike off road much.

 

[mcbrien]

eiv712 , thanks for posting this. Sounds like if things aren't shifting well
this should be checked .

 

[snakebitten]

First of all, excellent writeup!
We should be grateful that this is so well documented for the entire worldwide Tenere community.

And yes, that tech was really good!

So, the Tenere forum finally has a thread that legitimately used the term "catastrophic" in its description of the failure. Amazing. We are now whole. The Tenere is a real bike with real potential breakdowns.
It took a long time.

 

[~TABASCO~]

Great find... ::008:: I would hate for that broken part to fall down into the clutch or trans....

 

[ejy712]

Was just wondering if you ride your bike off road much.

The most "off road" my S10 has been is fairly smooth gravel. And probably less than 10 miles of that in 29,000 miles. I also have about 1,000 miles of 2 up. But I have done a lot of Pennsylvania chip seal, really bumpy.

I ride year around, mostly in Tour mode. This time of year I am fairly consistently above 50 mpg. I typically get 12,000 miles+ on rear tires. So I'm hardly a bash and trash rider. I don't think I am a violent shifter. I always use the clutch. I'm retired and do my own maintenance. I try to keep everything clean and properly lubed. So I don't think abuse is the problem.

Since no one else is reporting this problem I suspect that I got a bad spring. An inclusion in the steel could have created a stress riser causing the original crack. Unless this becomes a wide spread problem it's probably not worth the effort to track down.

::021::

still applies...

 

[ejy712]

Great find... ::008:: I would hate for that broken part to fall down into the clutch or trans....

Roger that! I had the same thought. The mechanic did say that he had seen this before on other bikes. And that he had seen broken ones laying in the bottom of the case. He indicated that he had not seen them cause a problem. Hard to believe, but I trust this guy's experience completely. He's probably forgotten more about motorcycle mechanicals than I ever knew...

 

[Rasher]

How long did the repair take, it looks like an engine strip job from the parts diagram :question:

 

[OldRider]

This kind of spring is used on a lot of motorcycles and four wheelers made by all the manufactors. Over the years i've seen several break and I don't think it's anything a rider has any control over by the way he rides or shifts. It's a spring and they do break.

 

[snakebitten]

Who'd a thought? The Tenere has a Doohickey!

 

[scott123007]

This kind of spring is used on a lot of motorcycles and four wheelers made by all the manufactors. Over the years i've seen several break and I don't think it's anything a rider has any control over by the way he rides or shifts. It's a spring and they do break.

You are correct, no amount of abusive shifting can have any effect on that spring, by the design of that shift shaft and the stop pin. It was a bad spring, that's all.

 

[Karson]

Who'd a thought? The Tenere has a Doohickey!

Where's Eagle Mike when you need him!

 

[ejy712]

How long did the repair take, it looks like an engine strip job from the parts diagram :question:

Good question!

The repair took about an hour (which is what I was charged -- no complaints). The right side case cover (where you pour the new oil) was removed. You will need a new clutch cover gasket if you check it. I lucked out. The old gasket came off without tearing...

 

[roll_it_on]

Pretty sure the clutch basket would have to be removed as well due to the mechanism hiding in behind there and no access to the shift shaft with it in place. I have had my clutch basket out a few different times and it is a very simple process on these bikes. You don't even have to drain the oil. This bike is one of the more well thought out (repair wise) that I have owned. ::012::

 

[Rasher]

Pretty sure the clutch basket would have to be removed as well due to the mechanism hiding in behind there and no access to the shift shaft with it in place. I have had my clutch basket out a few different times and it is a very simple process on these bikes. You don't even have to drain the oil. This bike is one of the more well thought out (repair wise) that I have owned. ::012::

Great, a fairly simple job, I was concerned the spring was beyond easy reach (i.e. inside gearbox)

I agree this is quite likely a one-off, but worth bearing in mind, and checking if a clean of the shaft does not completely resolve any shift issues ::008::

 

[kenbike]

Can you provide the part number from your repair order? Might be worth picking one up and changing it out next time I work on the bike.

 

[cosmic]

@ejy712
Thanks for posting. I guess i'll look into it too. I have to grease the lever every 1500mls tops, otherwise downshifting becomes pia. But then again, when i clean/grease it, it's like new again. Hm...


©

 

[AVGeek]

I'm putting this on my list to check. I've never liked the way mine downshifted, especially as compared to my FJR. I did the shaft clean and grease, but it still feels difficult to engage on the downshift, upshift has been fine...

 

[patrickg450]

Same problem I had, glad you got yours fixed as quickly as you did. I had to wait on parts, just bad luck really. After we got the part they basically looked at the good one to figure out what was the hang up, sorta had to have a good one to compare it too.

I did not get as good of a a response as you did.


http://www.yamahasupertenere.com/index.php?topic=8095.0

 

[Mark R.]

I think what is even more amazing for you is that they had one in stock, and you could be on your way. Most motorcycle parts have to be ordered. This must be a common spring on many Yamaha units.