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  # 1  
Old 20-05-10, 08:57
bonjo bonjo is offline
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chain slack confusion

why it is that on my XTR-09:
-when I set the slack to 35mm: less vibration, smoother throttle control & pick up

- when I set it to 45~50 mm: a lot of vibes, throttle less smooth and pick up from 40~45 mph in top is horrible???????

When I got the bike (new) I noticed the chain slack was around 30 mm, I changed it to around 50. Now 2000 miles later, I decided to make it tighter than the 40~50 spec in the handbook & I got the above result.
  # 2  
Old 20-05-10, 09:04
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Kev Kev is offline
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Quote:
Originally Posted by bonjo View Post
why it is that on my XTR-09:
-when I set the slack to 35mm: less vibration, smoother throttle control & pick up

- when I set it to 45~50 mm: a lot of vibes, throttle less smooth and pick up from 40~45 mph in top is horrible???????

When I got the bike (new) I noticed the chain slack was around 30 mm, I changed it to around 50. Now 2000 miles later, I decided to make it tighter than the 40~50 spec in the handbook & I got the above result.
I agree I run my chain tighter for less drive line shunt. It's a big single that's what they do.
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  # 3  
Old 20-05-10, 10:24
bonjo bonjo is offline
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thanks
great to know of your similar experience.
I am inclined to reset the slack tighter again, the pick up & roll off are so much smoother. I guess less vibes & shunting can only be good.
What's interesting is that the bike when new was delivered with a tighter than handbook chain.

I also noticed a 5 mm increase chain slack between the bike on paddock and side stand which is as I expected
  # 4  
Old 20-05-10, 10:41
uberthumper uberthumper is offline
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Quote:
Originally Posted by bonjo View Post
thanks
What's interesting is that the bike when new was delivered with a tighter than handbook chain.
Not that surprising. At the 6k service Tamworth Yamaha wound mine up so tight it was singing on the way home. Idiots. I wound a full turn off the adjusters when I got home.

If you're going to go tighter than recommended, make sure you check there's still a bit of slack through the entire suspension travel. I don't know about the XTR, but if the Ten is less than ~50mm on the sidestand, it goes tight with my weight pushing down on the pillion seat.

I just deal with the driveline shunt.
  # 5  
Old 20-05-10, 10:51
borus borus is offline
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Although I noticed that tighter means smoother ride, my chain is on the loose side. I've heard and read many times that too tight means extra worn out on the axle/shaft (the thing with sprocket that goes into your gearbox).

@Kev: don't you think that tight is a risk for the axle?
  # 6  
Old 20-05-10, 11:09
RickM RickM is offline
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Quote:
Originally Posted by borus View Post
Although I noticed that tighter means smoother ride, my chain is on the loose side. I've heard and read many times that too tight means extra worn out on the axle/shaft (the thing with sprocket that goes into your gearbox).

@Kev: don't you think that tight is a risk for the axle?
Speaking from personal experience I'd definitely leave it on the loose side. Too tight and you risk trashing the gearbox output shaft bearing - and that means complete engine strip down. Happened to me once on my Africa Twin.
  # 7  
Old 20-05-10, 13:55
Denny Denny is offline
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Quote:
Originally Posted by uberthumper View Post
it goes tight with my weight pushing down on the pillion seat.
And even tighter fully loaded with luggage and pillion. When going on long trips I get my wife (should use two of her as she is almost half my weight) to sit on the bike with luggage on and then adjust the chain at the tightest point.
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Old 20-05-10, 18:22
bonjo bonjo is offline
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OK I put pen to paper (PC application actually) & drew the swing arms/ chain movement and positions for normal & loaded positions (6deg compression).
What I actually saw was that when the whell is pushed up, the front to rear sprocket distance is actually marginally reduced!!
So this means that contrary to what we say, there should be an increase in chain slack??
Unfortunately I can't see a way of uploading the drawing to find out where I've gone wrong. Shame!

I called my dealer & talked about this, they said they tend to set the slack to somewhere between 30~35mm when they do the PDI. So this is what I'm gone a do
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