Im confused about all the chain tensioner problems

I enjoy the chain tensioner discussions also...mostly because the root cause of the problem has nothing to do with the tensioner itself. For some reason, the "why" seems to have been lost.

If you have a bike that has a frame with 3/4" or greater slots in the drop-outs, and the chain clears the frame...don't bother with the tensioner...it isn't needed.

For those who haven't owned motorcycles, believe it or not, even the smallest do not use chain tensioners.

90% of the, coaster brake, beach cruisers have a frame set-up that makes the tensioner null and void.

Now back to the problem:

Let's assume that you have a Schwinn Jaguar. This is a multi-speed bike with a deraileur. By design the frame need only have enough depth of slot in the drop-outs to mount the wheel. There are a lot of bikes with frame designs that are similar, in regards to rear wheel mounting. This frame design offers virtually zero wheel adjustment along the length of the frame. The slots are actually slanted to about 20 degrees off horizontal. A chain tensioner is needed for this type of frame!

Why does the chain tensioner plow into the spokes? It doesn't...you inadvertently made it happen!

It's simple; the rear sprocket isn't running true, or the tensioner isn't tight.

For all of the new guys out there, and those still having problems with the tensioner...there is a real easy fix!

When you are done with your build, have someone hold the clutch in...lean the bike over on the kickstand so that the rear wheel is off the ground...spin the rear wheel by hand to see if the chain gets tight and then goes slack!!! If it does; don't ride it until you have adjusted the rear sprocket so that it runs concentric to the wheel!!! This isn't rocket science guys. If the chain gets tight, the tensioner is going to move...move in the direction of the spokes! The engine mounts will be stressed to the point of the never ending threads regarding broken motor mounts. Ensuring that the rear sprocket is running true, is the #1 build concern.

In a proper installation the tensioner should only serve to keep the chain off of the frame buy redirecting the chain at an angle that will not allow chafing.

The only time that the chain tensioner actually has to work...is when starting the engine. This is a minor load, and there is no reason why the chain tensioner would ever plow into the spokes if it were securely mounted.

The problems with chain tensioners are related to improperly installed "rag joints"...nothing else.

Jim
 
Good advice and as always, correct. The problem is that newbies won't see it until its too late and they're replacing rear wheels or spokes. Its really too bad that the suppliers of the 2 stroke kits do not heed this advice and include it in the kits that they sell. Better yet, that a newcomer do some reading and research before attempting to ride their bike for the first time. Without a doubt, the chain tensioner/rag joint/sprocket alignment issue is the biggest shortcoming with the Chines 2 stroke engine kits. I'll take this opportunity to challenge all of our sponsors who sell the kits to take the advice of the experienced builders here and provide it to their customers. I'll go so far as to offer to write the information which you, as vendors can copy and place in each kit you sell. If anyone else wants to volunteer to do this let me know or maybe we can collaborate on this project. Vendors, sponsors??? Any response from you?
Tom
 
Jim, Bill,
I agree to a point, but not every person who buys a kit is a member here, or the other place. And, its like you and I said; the information is here, lots of it but how often do you still see a post from a new guy with this: "My tensioner came loose and went into my spokes. What do I do now?" Hardly a week goes by without seeing those words or something similar. Yes, the kit suppliers provide instructions but the instructions do not stress the importance of proper sprocket/chain alignment, tensioner installation or warnings about what will happen if things aren't put together correctly. We'll never be able to help that certain segment who have little to no mechanical skills and would be unable to comprehend the significance of the instructions but I feel that a good many would benefit from having just a little clearer picture of how to achieve a successful build. I'd simply like to provide them with the information to help alleviate some of the frustration that is all too often encountered by first time builders.
I'll concede that supplying the information in the kit might not be the answer or feasible, but what is? Do we make reading certain threads mandatory prior to registration? Not a good idea. So we're left with hoping that the new comer will read? It's obvious from the questions asked here everyday that many will not take the time to read before asking a question that has been asked and answered numerous times before. No other aspect of the installation is as important, I feel, as proper drive chain installation, so if a guy has problems with his clutch cable or wiring, not a biggie, no damage or potential injury will occure, but having the rear wheel lock up at 15 to 20 mph is another story. I'll give this some thought and get back to you.

Tom
 
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If these things were regulated the instructions concerning the tensioner would take up a whole page at least. Although I have never had a problem with stock, a better design would also be mandatory.
 
Mmmm yeah. If a device such as the chain tensioner were to be a front-wheel affair...

...... given the frighteningly greater consequences of a front wheel lock-up, a design such as the chain tensioner would be simply not good enough.

But it's all down to sprocket concentricity. As ever Manic is right on the money.
 
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