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Drive chain slack


Slee

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Hi all

 

I have a 2017 MTO7 Tracer. The manual I have states 30 to 35mm slack as pictured. My dealer was adamant it should be 40 to 45mm. Is the dealer right or go with the manual? 

 

Cheers

 

Slee

Screenshot_20190302-200102_Adobe Fill & Sign.jpg

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I loose chain isn't a bad thing if it isn't TOO LOOSE (real saggy) so I would think that somewhere in between 35 to 40 would be fine. Chains do loosen up gradually after they've been set so being a little on the loose side isn't going to hurt it. They say a loose chain is a fast chain so that's a good thing.

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Beemer

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I'd trust a manual over a dealer.  Heck, I'd trust a rotten pile of dog poop over a dealer.

Maybe show the manual to the dealer.  I'd check with a mechanic who actually works on bikes for a living instead of the dealer.

Like @Beemersaid, a little loose is better than tight and splitting the difference won't hurt.  Just keep an eye and ear on it.

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  • Global Moderator

 

Yamaha designed the bike, and wrote the manual to those designs. The dealer should follow the manual, but I've yet to find one that does.

Flat-rate hours are a horrible system, and lead to shoddy repairs. Then you have the salesmen and service writers at dealerships that have likely never turned a wrench before claiming they know what's wrong/giving incorrect advice. 

The fz/mt likes a loose chain but you don't want it bouncing. Follow the manual. 

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ATGATT... ATTATT, two acronyms I live by.
 

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22 hours ago, firstyammerha said:

throw in the oil sight glass too.

What is wrong with the oil sight glass?

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firstyammerha

as Beemer says, the engine and bike performance overall is top notch. It has its flaws(as do all bikes) but you'll learn to live with them. Or make mods to lessen or eliminate  them. Or buy another bike.My gripe with the oil sight glass is when you fill the engine with oil after a oil and filter change, the glass is showing over filled. I use a Ratio-Rite to fill the engine with the amount of oil required by the owners manual so either the manual is wrong or the sight glass is in the wrong spot. Maybe the drain plug is in the wrong place. Only engineering knows for sure. The gas gauge is really bad. I generally put in around three gallons of gas after running all the bars off the screen and going into the reserve 40 miles or so. I'm too cautious to run the tank dry to find the true tank volume and as far as I can see, no forum members have done this to find true empty and actual tank capacity. Myself,I've accepted the bikes as it is  and just throwing my .02 in. 

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Its a mystery to me, why Yamaha did the gas gauge the way they did. The fuel sensor is just a variable resistor (~10 ohm full, ~215 ohm empty), they would only have to adjust the firmware of the dashboard. I  bet if you decrease the measured resistance by putting a little resistor / poti (around 2 kΩ ?) parallel to the green/white cable  coming from the fuel float sensor and ground, you could even readjust the fuel gauge by yourself.

 

Btw, the oil sight glass is perfect, with the bike on its center stand at a leveled surface the oil is close to the maximum - mark after adding 2.6L of 10w-40

Edited by ElGonzales
added line
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  • 3 weeks later...
  • Premium Member
howworkclutch

Ignore the manual. Believe the dealer. The manual calls for too much tension. Especially with the spongey stock shock. 

-HowWorkClutch

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  • 11 months later...
On 3/2/2019 at 11:38 AM, rider said:

I'd trust a manual over a dealer.  Heck, I'd trust a rotten pile of dog poop over a dealer.

Maybe show the manual to the dealer.  I'd check with a mechanic who actually works on bikes for a living instead of the dealer.

Like @Beemersaid, a little loose is better than tight and splitting the difference won't hurt.  Just keep an eye and ear on it.

Well, having been a salesperson at a dealership owned by a motorcyclist and having all motorcycle enthusiasts in it other than a few of the women who worked there in the office and the one guy that lasted about three months that was a car guy, you guys just need to become better judges of who knows what and where to find them.

 

11 hours ago, Josh2019mt07 said:

Go with the manual all day

Now on the topic, having a KLX250 dual sport and a manual that has their recommended slack, I found they were off by about 10=15 mm.  I went by the real way to know - 

  • Support the bike using a jack in the center or holding up the rear by the frame - not by the swing arm
  • loosen the axle nut
  • detach one end of the shock or use a tie down to pull the swing arm until the counter shaft, swing arm pivot, and axle are in line
  • adjust the chain until there is about 25mm (1") of slack at the tighest point
  • tighten the axle nut
  • reattach the shock or release the tie down that is holding the swing arm up
  • extend the suspension fully out and measure the slack in the chain - make a note of the amount of slack, that is what you need.

I adjusted my Zephyr 550 by the book and it was too tight.  When I checked this way I found it was too tight by the book.   It ran around 50-60mm mid-swing arm.  the KLX250 runs around 60-70mm mid-swing arm. 

As said, loose is better than too tight.  Too tight can accelerate wear on the pins (the part that wears causing the notorious "stretch") damage wheel or counter shaft bearings, possibly crack the main case.  It would have to be so worn it would drag the ground to derail and you'd have to be blind and deaf not to see and hear it.  The sprockets would be so hooked you could go fishing with it.  I think you get it.   It will take something like wheel alignment or something forcing against the chain to derail it.

A good chain will not derail.  Here is a shot of the chain on a motocrosser and they get hammered a lot harder than any XSR will.  Check out the slack on this flat tracker, ready to run - and they're lowered, a motocrosser would have more play yet:

 


chain slack galore.jpg

Edited by klx678
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Dirt bikes need a looser chain because of the long travel suspension.  The front sprocket is offset from the pivot point of the rear arm hence why tension changes throughout suspension motion.

To the OP.  Maybe the dealer measures off the arm and takes into account the guide thickness 😕

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Obviously, that is why I pointed out how to find what is actually needed instead of relying on either source.  The tightest point will be when those three axes align.  Pretty simple.

The point of the off roader, which is actually set up with around maybe 7-8" of suspension for flat track, closer to the 5" of the FZ than an MX bike's 12", I wanted to show how much slack they run without derailing chains.   

To the OP find out for yourself what is right.

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