Trouble with chain alignment and tensioner stability.

[BlueDestiny]

I am having some difficulty getting the drive chain to fit properly. The problems are a huge amount of vertical play and the tensioner wheel being pulled sideways into the spokes.

Here is a picture of the vertical play. As you can see the chain goes way up and down, but despite that I can't seem to make it any shorter and still fit the tensioner.


Here I've tightened it as much as possible with just the tension pulley. It worked OK without the clutch.


But as soon as I engage the clutch and turn the wheel, it falters and yanks the pulley sideways, forcing the chain to rub against the tire.


The chain itself doesn't rest evenly on the pulley wheel, which might be causing it to pull inward.

Instead of being inline with the groove on the pulley like this: |I|

It sits at a slight angle like this: |\|

 

[Slogger]

You can probably take a link out of the chain since it's so sloppy. The tensioners are always needing attention, mine is bent to a sort of an S shape to get it squared up under the chain right.
Using some blue loc-tite on the nuts and putting a coat of plasti-cote on the frame under it should keep it out of the wheel.
Hope this helps, good luck to you!

 

[tomtruty]

Please reconsider using the chain tensioner on the drive chain. Remember the top chain in under tension when the engine is pulling your bike. When you decelerate or start your engine the bottom chain is under tension. If your engine kicks back your spindly tensioner will bend into the spokes and cause big problems and possible physical pain! Spring loaded tensioners don't work well unless there's very little action and even then the chain is liable to pop off when you start your engine. Adjust the chain length as close as possible without tensioner. You may need a half link to get the pedal chain somewhat tensioned when the drive chain is right.

 

[BlueDestiny]

Thanks for the replies. I'll see if I can ditch the tensioner and manually adjust the chain using the little bracket space things (walkouts?) in the rear wheel fork.

 

[bluegoatwoods]

You definitely want to shorten your chain. It's much longer than it needs to be.

tomtruty is right in suggesting a half-link in order to get both chains tensioned properly. But there's another way. Shorten your engine chain until it's perfectly tight without a tensioner. Then use that chain tensioner on the pedal chain. It'll need to be hung upside down on that side, pushing downward on the bottom chain run.

You can get a rivet extractor from some of the vendors that you'll find on the left side of these pages. I believe www.sickbikeparts.com carries them. If not, one or two of the other sponsors will.

Or you can always cut (but not lengthen) a chain using a bench grinder to grind off the rivet head. Then just punch the rivet out.

And if you do overcut it, then you could always get a bit more chain and master link from a sponsor. Then your bike chain will have two master links and you can add or subtract a small chain of links in between.

I just cut a 415 chain the other night using a bench grinder. I wish I'd taken photos. But if you need that kind of help, then please feel free to come back here and say so. I'll cut a piece and take pics.

You would need to actually say so, though. For all I know you already know how to do this. Without being told that you need it, then I'll be doing other things.

 

[crassius]

First, you need the tensioner to feed chain EXACTLY straight onto bottom of rear sprocket - turning the wheel should place the chain such that the teeth are right in the middle of the rollers. Next, you need to bolt the tensioner tightly to the frame. Some times the frame is a bit too small for a good grip on it, so I take an inch or so of old handlebar and cut it lengthwise into 2 "C" shaped sections to put under the tensioner mount (these can also help to move tensioner so it is straight by putting both on a side where it is needed. Sometimes, I also need to replace the two 4.8 chinese bolts with two 10.9 or 8.8 american bolts to get it really tight.

I've done hundreds this way & all work well.

 

[dougsr.874]

Chain is way too long....take out links....also picture if so dark I can't tell...but it appears that rear sprocket is dished in.....it should be dished OUT to keep chain off of tire...

 

[butre]

throw away that stock chain tensioner and buy or make one that bolts to the engine. those things are dangerous, and I'm surprised nobody has gotten killed over them yet. If I was in traffic when mine went I probably would have been.

 

[crassius]

I've tried some near the motor, they don't steer chain straight enough onto rear sprocket.

 

[BlueDestiny]

Chain is way too long....take out links....also picture if so dark I can't tell...but it appears that rear sprocket is dished in.....it should be dished OUT to keep chain off of tire...

I'll be damned, you're right. The sprocket is dished inwards which would explain the chain running at an angle and throwing the pulley off. The chain just barely clears the frame with no tensioner, so it might be better to attach it to avoid damaging the bike.

Now all I have to do is re-lengthen both chains, flip the sprocket and try not to have an aneurysm because this is the fourth time I've taken off and removed the darn thing.