chain tension questions, need help

Lonewolf

Member
May 30, 2002
494
0
tonight i went to adjust the tension in my chain and because im an idiot i can figure it out. i actually never did it myself before. what i did was i put the bike up on the stand, loosened the axle nut, then played around with the adjusters until i had the chain at the correct tension. but i noticed there are little notches in the swingarm that you line up with the metal block with notches in it that the axle goes through, should they be the same on both sides? i couldnt get them to be on the same mark on both sides should the be? but i would set the tension then tighen up the axle nut and take the bike off the stand and the chain would be way to tight so i kept messing around with it and i still can get it right, its always too tight. can someone go through the process with me, im sure im doing something wrong.
 

Ol'89r

LIFETIME SPONSOR
Jan 27, 2000
6,958
45
Originally posted by Lonewolf
its always too tight. can someone go through the process with me, im sure im doing something wrong. [/B]

Lonewolf.

Take it off of the stand. You have to compress the suspension to get the correct adjustment. When you compress the rear suspension, you will notice that the chain will get tighter to a point and then start to get loose again. This has to do with the pivot point on the swingarm in relation to the engine sprocket.

Lean on the seat or have someone push down on the rear of the bike. When the chain gets to its tightest point, adjust the slack. The lines on the adjusters should line up equal on both sides. If you don't already have one, you may want to buy a service manual. :thumb:

Just my $ .03 (I raised my prices.) :)

Ol'89r
 

Jon K.

~SPONSOR~
Mar 26, 2001
1,354
4
After you establish (through the process that 89r just described) how tight the chain should be; make a note of how tight the chain is while on the stand. If you can make a mental note of it, and stick to it; then the chain can be adjusted on the stand.

The marks on both sides of the swingarm do indeed need to match.

Once I adjust the chain; I always stick a screwdriver handle in between the chain and sprocket (egad!) and gently roll the wheel backward to take up any slack in the adjusters. This of course BEFORE the axle is tightened up.
 

sethaidyen

Member
Jul 7, 2003
4
0
I just went through this tonight with a new chain. First of all yes the marks do have to match or you will wear both your sprockets and your chain quicker, second take a tie down put one hook in your sprocket and run it over the top of your seat (it is easier if you release one end of the shock so your not fighting it) and then hook to your brake disk and cinch it down till it looks like the swingarm and all look rather straight. Measure the distance between centers of your front sprocket shaft and your rear axle center take that dimesion in inches and convert any fraction left over to decimal (like 24 1/2 to 24.5) and then multiply that by 2-3% that will be your chain sag. Now losen your axle nut, bike still tied down and run in your adjusting screws. Kick your tire forward. Now you will probably have to much slack so take a level and lay it across your sprockets above the chain and grab your chain and pull it down and measure between bottom of level to top side of chain till you reach your sag all the while keeping the same marks on the adjusters. Hope I helped. What kind of bike is this?
 

Lonewolf

Member
May 30, 2002
494
0
thanks for your help guys, i got it a little better, i thought it would be easier than it was though. the cahin pretty needs replaced, it stretched pretty bad.
 

MotoGreg

Member
Sep 23, 2001
80
0
When you compress the rear suspension, you will notice that the chain will get tighter to a point and then start to get loose again. This has to do with the pivot point on the swingarm in relation to the engine sprocket.
If you have a '02 or newer CR or CRF the chain is tightest at suspension full extension... when the bike is on a stand with the wheel off the ground. This is because the swingarm pivot centerline is lower than the countershaft sprocket centerline. Look at a pic of RC's bike and you'll notice it has no chain slack when the bike is on the stand. Yesterday, I was standing next to McGrath's CRF Supermoto as Chad Watts did the post race teardown and the chain was adjusted tight as a banjo string, zero slack.
 

High Lord Gomer

Poked with Sticks
Sep 26, 1999
11,788
35
The CRF manual suggests 1" - 1 3/8" slack at the midpoint with the bike on the stand. It does seem tight compared to other bikes, but any looser and it makes a bunch of noise.
 

rmcmichael

Member
Jun 27, 2002
47
0
I made myself a chain slack ruler. I cut off a piece of 3/8 wooden
dowell 15.5 cm long. Then I photocopied 15.5 cm of a metric tape
measure. I pasted the photocopied piece around the dowell and then
covered the paper and the dowell with clear Scotch tape and then
sealed the ends with a drop of paint. Now checking chain slack and
chain stretch are so easy, guys often ask to borrow it.

I run 30 mm chain slack, per the Honda Manual, with the bike on the
stand. I used to run 40 mm on my YZ250. Yes, it's tight, but I tend
to go by the book.
 

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