Chain Adjust with drop links

[Olythom]

OK... I am going to toss this out there to get recommendations from the technical wizards out there.

Skookum has 12,000 miles in her and I have always kept the chain within specs. A while back, I installed a pair of home-made chrome-moly drop links and slid the front tubes to lower the seat about an inch.

Considering that the drop links have changed the swingarm angle, do I need to alter the original chain tension setting when it is sitting on the sidestand? My concern is that, with the altered swingarm angle, the lower portion of the chain is actually running physically closer to the swingarm than the stock setup and if I use the original slack measurements, the chain may be slapping the bottom of the swingarm more frequently.

Thanks in advance for your consideration.
>Thom

 

[lootzyan]

If your last chain slack adjustment was before you lower a frame, measure chain slack now, make a note and keep that way. The difference in measurements should be no more than 5 mm.

 

[mtiberio]

for one thing you should be checking your chain tension with enough weight on the bike to get the counter shaft, swingarm pivot and rear axle in a line (the tightest point). This is the way to adjust the chain on any bike. I do it by putting my belly on the saddle and leaning over the bike and reaching down to the chain.

 

[Beemerphile]

Considering that the drop links have changed the swingarm angle, do I need to alter the original chain tension setting when it is sitting on the sidestand? My concern is that, with the altered swingarm angle, the lower portion of the chain is actually running physically closer to the swingarm than the stock setup and if I use the original slack measurements, the chain may be slapping the bottom of the swingarm more frequently.

Yes. You need a new baseline value for chain slack. Adjusting the chain to spec before the links were changed as lootzyan suggested would have been the easiest method of obtaining it. Whatever the slack is after the link change would be your new baseline. If you didn't do that, and you don't want to temporarily reinstall the stock links to find out, then you must find a way to compress the rear suspension until the front sprocket, the rear sprocket, and the swingarm pivot are aligned in a straight line. The most accurate way to do the new baseline is to (1) raise the rear wheel (centerstand or jacks); (2) disconnect the shock linkage; (3) lift or jack the swingarm until the three points are aligned; (4) adjust the chain for 1/2 inch of slack; (5) reattach the suspension linkage and check the slack. That would be your baseline. It will be lower (less) than the 1-3/8" factory spec.

A whiz-bang mathematician could solve it with a pencil. I'm not willing at my advanced age to give it sufficient thought.

 

[Deleted member 5383]

for one thing you should be checking your chain tension with enough weight on the bike to get the counter shaft, swingarm pivot and rear axle in a line (the tightest point). This is the way to adjust the chain on any bike. I do it by putting my belly on the saddle and leaning over the bike and reaching down to the chain.

I do it with a ratchet strap and a straight aluminum extrusion. No jack, no, disconnection of anything. Just some protecting stuff beneath the cinch strap where it touches bike parts, running the strap through the rear wheel. When the center of each sprocket is in line with the center of the swingarm pivot point (using the long aluminum as a straighedge), i know i've got it cinched down to where the chain is the tightest. then you can see how much chain slack there is at that tightest point in suspension travel, and adjust accordingly.

 

[Olythom]

Great stuff guys. In my gut, I knew that the slack measurement should be reduced but I did not envision the sprocket-pivot-sprocket line as a reference. You guys are awesome. Thanks.
>T

 

[lootzyan]

... The most accurate way to do the new baseline is to (1) raise the rear wheel (centerstand or jacks); (2) disconnect the shock linkage; (3) lift or jack the swingarm until the three points are aligned; (4) adjust the chain for 1/2 inch of slack; (5) reattach the suspension linkage and check the slack...

I also found it to be the best and safe way for taking slack measurement in various suspension positions. (I guess that "...(4) adjust the chain for 1/2 inch of slack..." must be a typo)

 

[lootzyan]

... I did not envision the sprocket-pivot-sprocket line as a reference....

No, it's not. Reference is whatever slack requirements Honda provides in owner's and service manual, which is 30-40 mm (1.2-1.6), measured on sidestand.
It was stated here by many that slack measurement difference on sidestand and centerstand is in average 5mm more. From my measurement, in sprockets aligned position slack is 3 mm less than on sidestand.

In your case, if you lowered your NC by close to 1" (25mm), you don't have to guess what your new chain slack should be. Honda already give us this information in Service Manual for NC and CTX.
Your new slack is 25-35mm (1-1.4) on sidestand.

 

[Beemerphile]

I also found it to be the best and safe way for taking slack measurement in various suspension positions. (I guess that "...(4) adjust the chain for 1/2 inch of slack..." must be a typo)

No, when I checked the baseline of my NC with stock suspension, the recommended 1-3/8" of slack became 1/2" when the three points were aligned. So working backwards with the customized suspension, if there is 1/2" of slack with the three points aligned, then the new baseline is what ever slack results when the modified suspension is at unladen height. 30-40mm slack on a shortened suspension is most likely excessive. You and I have gotten wrapped around the axle on this topic before. We seem to see it differently.

 

[lootzyan]

No, when I checked the baseline of my NC with stock suspension, the recommended 1-3/8" of slack became 1/2" when the three points were aligned. So working backwards with the customized suspension, if there is 1/2" of slack with the three points aligned, then the new baseline is what ever slack results when the modified suspension is at unladen height. 30-40mm slack on a shortened suspension is most likely excessive. You and I have gotten wrapped around the axle on this topic before. We seem to see it differently.

Too late for me to recheck my measurement on NC. I only can depend on my memory (unreliable) or on some of my old charts which were made based on my measurement and CAD frame geometry analysis.

For lowered NC700X/XD I would use slack requirements for NC700S or CTX700, 25-35 mm. Their ground clearance is 25-35 mm less than of NC700X/XD.

 

[Olythom]

Thanks guys........ I truly appreciate your input.
>T

 

[Olythom]

Thanks for the help guys.

Admin... Please close thread.
>Thom