Another chain question:


6 replies to this topic
  • Justin89

Posted August 10, 2007 - 04:47 PM

#1

Hey guys, I just adjusted my chain today and it was perfect while on the stand. As soon as I took it off the chain got really tight. When I put it back on again it was right back where it should be. I also noticed that when I spin the tire the chain is perfect in some spots and tight in others. (while on the stand) Is this normal or am I just to retarded to figure out how to tighten my chain. Thanks!:worthy: :ride:

  • grayracer513

Posted August 10, 2007 - 05:46 PM

#2

Your chain is worn unevenly, causing it to have sections that are "stretched" farther than others. Stretched is in quotes because the chain very rarely actually stretches in the plastic sense. What happens is that it wears at the bearing surfaces of the pins and bushings so that all the wear of all those pivot points adds up to a chain that's longer than it's supposed to be. Review the method of measuring the chain wear in the manual. If any section of the chain measures at or over the wear limit, replace it. Your sprockets will likely need replacement as well.

  • USED YZ426F

Posted August 11, 2007 - 03:47 AM

#3

How much slack is in the chain when it is on the stand?

I don't want to insult you, but a chain should have 3/4-1" of slack when the driveline is in a straight line. The driveline is the front sprocket, swingarm pivot and rear sprocket.

By that I mean that if you draw a line from the center of the front sprocket, through the center of the swingarm pivot to the center of the rear sprocket and load the rear suspension until all three of the above line up, then adjust your chain for slack.

The only reason that I can think of a chain being "tight" in some areas and "loose" in others when on the stand would be binding links in the chain or damaged bearings in the wheel. Does the wheel spin freely when the chain is off? Have you checked the chain for binding off the bike?

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  • grayracer513

Posted August 11, 2007 - 04:20 PM

#4

I don't want to insult you, but a chain should have 3/4-1" of slack when the driveline is in a straight line. The driveline is the front sprocket, swingarm pivot and rear sprocket.

By that I mean that if you draw a line from the center of the front sprocket, through the center of the swingarm pivot to the center of the rear sprocket and load the rear suspension until all three of the above line up, then adjust your chain for slack.

At the tightest point, which you did correctly describe, the chain needs 1/4" of real slack (up and down) per foot of the free hanging run. On a YZF, since that's about two feet, it needs a half inch at that point.

What you'll find is that the specification in the manual (1.9 to 2.3" from the swing arm to the highest point the chain can be lifted to) is based on the chain being that tight as the swing arm moves through the tightest point. In other words, if you adjust it to a half an inch with all three centers aligned, then measure it again as described in the manual, it will be right at 1.9". So, you could do it the hard way, or just go by the book.

Wheel bearings won't cause the tight spots in the chain because they don't cause the wheel to rotate eccentrically. A worn out of round sprocket could, As could the tight links you mentioned, but those you can pull out straight by stepping on the chain. Uneven chain wear is by far the most ordinary cause of the problem reported here.

  • Justin89

Posted August 11, 2007 - 10:31 PM

#5

How much slack is in the chain when it is on the stand?

I don't want to insult you, but a chain should have 3/4-1" of slack when the driveline is in a straight line. The driveline is the front sprocket, swingarm pivot and rear sprocket.

By that I mean that if you draw a line from the center of the front sprocket, through the center of the swingarm pivot to the center of the rear sprocket and load the rear suspension until all three of the above line up, then adjust your chain for slack.

The only reason that I can think of a chain being "tight" in some areas and "loose" in others when on the stand would be binding links in the chain or damaged bearings in the wheel. Does the wheel spin freely when the chain is off? Have you checked the chain for binding off the bike?


Yes the wheel spins freely without any effort and the tire seems to be straight from eye sight...the axle marks are at the "mark"and the adjusters are at the same mark on the bolts...i dont know how this could happen. :bonk:

  • grayracer513

Posted August 12, 2007 - 07:37 AM

#6

..i dont know how this could happen. :bonk:

I would have guessed that from your asking the question, but I just told you how twice. :excuseme:

  • Justin89

Posted August 12, 2007 - 04:44 PM

#7

Ok, i know i know. :bonk:





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