Chain it tight AND loose. Is this possible?

[back_online]

Okay before I get started let me clarify, I used the forum search and found no symptoms similar to mine, so no need to flame me if this has been previously discussed.

2nd, this is on my buddies bike which I help him for he's about as mechanically inclined as a potato.

His chain actually seems like it is stretched in one place. The reason I say this is it flops like a fish when he's riding beside me and I can even see where it has slapped the grease away and made a shiny spot on the upper travel path.

So I preformed a little maintenance by doing the following:

Placed the bike on its center kickstand. (duh)

Collapsed the shocks (with some twine to simulate a 170lb person is riding on it).
Adjusted the placement of the rear tire to bring the chain within its acceptable tightness.
Then, while the bike was in neutral, I spun the back tire, and WHOA!, it goes from loose to over tightened!

Okay, I'm thinking sprocket on the rear...warped (looks straight no wobble on front or rear)
So I mark the sprocket each time as it goes around where the chain is REALLY tight.
I was surprised to find out that it was a different ?pie section? on the rear sprocket that was the tight each time.

So I marked the chain as I slowly rolled the tire around, and low and behold about the same spot in the chain was always loose. And vica versa, the same portion was always over tight.

I've had dirt bikes with shark teeth sprockets from wheelies, and over torque, but never seen a chain get stretched like string cheese on one side.

So, I'm thinking maybe its not bending around the sprocket because it's rusty, corroded etc..

I removed it, (normal stock chain, no rubber o-rings etc) I soak it in gas to remove all the grease. Then I soak it in penetrating spray, to loosen it up a bit. I wipe it all done and do the screwdriver test on each side. You know, roll it over a stationary object and see how easily it bends over... I found a few that needed a little bending (by hand) back and forth, but nothing is visibly wrong with it. I clean it all up, reinstall it, and coat it with white lithium spray grease and adjust the rear tire again, to check, SAME THING.

So (if you're still awake) Time for the questions?
Have you ever heard of a chain getting a dozen or so Links Stretched to cause one side to be loose and the other tight?
Do you think I need to replace one or both sprockets when I buy a new chain? (even thought visibly they look perfect, almost no wear on either)


Thanks for your insights.

[saaz]

Not an uncommon problem. Often a small tight/loose spot may be due to sproclkets wearing, but you have covered this of. A chain can wear in sections, depnds on its quality, how it has been maintained etc.

A new o ring chain would definitely solve the problem if maintenance is the suspect...

[Anonymous]

Yes it is possible for a chain to stretch in given sections, seen it many times working on equipment.

[moto_dan]

Possible and probable. Every instructions I've ever read regarding chain adjustment says to adjust the chain at it's tightest point. Now as the chain and sprockets wear this condition will only get worse. If as you describe the chain is sloppy loose and then way too tight, then it is time for a new sprocket and chain set.

[Paul]

Yes, a chain will odten stretch like this,
Usually by very hard/violent pulling away (drag-race starts!)
Or it could have been standing a long time and have gone rusty in one section, when the bike is moved the rusty section wears more than the rest.
Or even by the cain having been overtight at some time in its life, and the suspension going to full travel.
Also when it's worn out it will be more stretched(worn) in some sections than others.
Solution - Buy a new chain!!!

[back_online]

Just ordered it today, thanks guys.

[roygang]

Sounds just like he situation with the GS I just picked up a few months back. Did new chain solve the problem (or did you also go new sprockets)?

[focus frenzy]

SHAFTIES RULE!!!!!!!!!!

[robinjo]

SHAFTIES RULE!!!!!!!!!!

Yeah right!

http://www.thegsresources.com/_forum/viewtopic.php?t=16921&highlight=

:twisted: :twisted: :twisted:

[mcycle-nut]

I don't think I've ever seen a bike with a perfectly even taut chain. There always seems to be tight and loose spots. Not so much on a new chain and sprocket set, but there still will be a difference. 8)

[Anonymous]

If you replace the chain - replace the sprockets also. I think this is in the motorcycle bible somewhere. And if it isn't there, it should be. 8)

[Anonymous]

Even with brand new OEM sprockets you need to check for their alignment. Something is haywire on my 400 which is causing my chain to rub on the outside edge of my rear sprocket instead of riding in the middle. :x

Steve

[Anonymous]

focus frenzy wrote:
SHAFTIES RULE!!!!!!!!!!

[Anonymous]

I had the same problem on mine ever since I've owned it . 3 sets of sprockets and 4 chains (Tsubaki or RK) have been thru it and all did the same thing. When I changed to a 17" rim the tight spot was gone. Turned out the origional rim had a machining flaw where the cushion drive is; just enough to drive me batty trying to figure out what the heck was going on all this time.

[skip]

My 1150 loves to stretch chains ( could be the burnouts or dragrace starts) and I have had that "tight spot" trouble before. I put a new chain and spockets this year and spent a little extra for the chain. So far (3000 miles) it has not stretched or if it has it is stretching evenly so there are no tight spots. I also have been behaving myself more than ever . Only a few dragraces and a few burnouts so that may be the answer.