Chain Wear Measurement.

[sgtslag]

Don't know if this is already in the FSM, but I came across it in my Motorcycles:  Fundamentals, Service, Repair textbook.  Thought it might prove useful, as it is not bike specific, but rather chain specific.  I'll list the full table, as some folks may find it useful for non-CB750 bikes, as well.

To measure properly, all slack needs to be removed from the chain, first, so pull the back wheel so that the chain is tight; then measure the distance of 21 pins, and consult the table below.  If the distance is equal to, or greater than, the distance listed below, for the specific chain type, it is too worn, and needs to be replaced.  Be sure to adjust the chain properly (loosen it, with the correct amount of slack), after measuring the stretch!  Riding the bike with the chain stretched tight, will destroy it, and both sprockets, very quickly...  It can also damage the transmission.


Make sure to check the condition of the sprockets, front and rear, as well.  A worn sprocket will wear out a brand new chain very quickly, no matter how well lubricated it is; a dry chain, will wear itself out, and the sprockets, very quickly, so keep that chain lubricated (every 300 miles is the usual specification).  Cheers!

Chain Size:          Pitch:          # of Pins to Measure:          Nominal (in./mm.):          Service Limit (in./mm.):

35                       3/8x3/16                     21                         7.5" / 191 mm                  7-11/16" / 196mm
420                     1/2 x 1/4                     21                         10" / 254 mm                   10-5/16" / 261 mm
428                     1/2 x 5/16                   21                         10" / 254 mm                   10-5/16" / 261 mm
520                     5/8 x 1/4                     21                         12-1/2" / 318 mm              12-3/4" / 327 mm
525                     5/8 x 5/16                   21                         12-1/2" / 318 mm               12-3/4" / 327 mm
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530                     5/8 x 3/8                     21                         12-1/2" / 318 mm              12-3/4" / 327 mm
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630                     3/4 x 3/8                     21                         15" / 381 mm                   15-7/16" / 392 mm

[Re-run]

Interesting. Never seen this before. The method I have used is to get the chain tight but then pull on the rear most link and see how far I can pull it off the sprocket. I forget the measurement but it is something like 1/16th or something like that. I write it down so I do not have to remember!

[TOOLS1]

That is some great information there. Thanks Sarg.
TOOLS

[shinyribs]

i like the sound of this method. I like things that are more or less cut in stone. A definite dimension is a good thing.Thx Sarge

[Piute]

                                   
 Ya sure Srg.that seems to easy

[wes]

im havin some issues with my chain and sprockets. please see my post and offer any advice you can. thanks