A DRIVE CHAIN TENSIONER THAT WORKS

[Petey]

Tried everything to get a chain tensioner to work, but no one carries torsion springs locally, and if they do its extremely light weight springs. Came up with a few different designs that kind of worked, but not as well as the one I found on ebay.
Chain tensioner

The perk is you don't have to order 100.00 dollars in springs to hope one works, may have to do a little work and your chain slap is gone, no more worrying where your going to find a snug fitting belt .

Here is the finished product

Need a small peice of 1" steel and drill two holes for 3/8 bolts then as well as some other hardware bolts nuts washers, etc. found at any home depot.

Placed at second hole providing reinforcement of assembly
Then you may have to play with spring a little to get desired snug fit, I drilled holes and advanced spring deflection, for a snugger fit, my chain is pretty heavy as well. they say 520, but it seems more like 525 530, or going closer to a larger size. here are few more pic's to get the idea.

 

[EricZ]

A very dangerous setup! The tensioner will get loaded during decel and, if it allows too much slack in the chain, there will be some serious damage to anything/everything the chain is near. A motorcycle chain should never be held under spring tension anyways. A constant chain tension can easily be achieved with the correct size idler sprocket mounted in the correct location.

 

[Theycallmecrash]

And God has spoken!

 

[Xb12sLt]

I was concerned about that also, the chain would be everywhere with that setup. It would be good if you could add an adjustable link instead of the spring.

 

[theMelvster6]

Notching the stock arm so you have a range of adjustment...then drilling and tapping it for a set screw. This works great. set your chain tension, tighten down the idler arm, then tighten the set screw so the idler can't move back under a load...boom! "Not a Jerry rigged mess"...as it's been quoted! Lol

 

[Petey]

Hatred is funny funny thing, ok first of all the chain will not mess up everything even on high rpm down shifts, then if it does your spring is way to light. So God can blow it out his a$$. As far as Jerry rigged cant be any worse then the factory belt tensioner. Jerry thinks your definition Jerry rigged is racist. There is a torsion spring involved here so what really happens is the spring gains in force when the further it is rotated, the screw is unnecessary. Then again spring tension, so the idea is look for chain wear after riding the bike hard, stoppies wheelies, heavy downshifting. If it shows sighn of wear rotate the spring 1 full compression, if that doesn't work going to have to find stiffer spring.
Spring tension on motorcycle or car a chain should have good results with time and patience, not excessive not too loose. Industrial multiple chain applications, as well as Timing chain, on other instances where its used. I guess why build a expensive tensioner when a engineer can put a sproket at perfect tension. I don't have that option, so had to use the expensive tensioner. So far it has been good what ever its worth, thats why I took the effort to post w/ pics.
So in short take it for spin and look for sign, like bear shit on a trail. You can tighten the spring by rotating it, if its too loose buy a heavier duty spring. Mine works fine but over time may need to tweak or perfect. I cant just hand a smooth ride to you, but did all I could.

 

[konarider94]

Some applications like a timing chain are fine with spring tensioners because they only see torque in one direction. With engine braking you will tension the underside of the chain and there is no way that spring can handle that. I think it's fine to use that but with a lot less slack in the chain. Try to push your bike forward in gear and see what it does. It looks like the chain might rub the swingarm.

 

[theMelvster6]

Whatever floats your boat...I'll run a race proven method to "adapt" XB's over to chain...ERICZ puts down big HP with his Turbo Buell with the method I suggested and many, many guys that race XB's use the same method too with GOOD results...

 

[Petey]

any time a engine or machine lets go of torque there is possibility of chain lash, then articulation of swing arm. stoppies, wheels, and other mass compression And release, causing mass articulation of swing arm, chain lash. But if its worthy spring tension, that increases tension as tension is added it should be ok. There are mods but I have been through this chain thing for a while with this bike, and you would have to be blind not to acknowledge the fact its one of the better ways of doing it. Other than spending the 2000.00 for the move to the EBR Chain XB set up.

The chain rubbing the swing arm, I put a thin layer of masking tape on the swingarm for liable place for the chain to rub. Naturally ride for a week and fine tune. Make sure no excessive pressures on sprocket where chain may wear teeth etc. Just thought I would post to help anyone who likes the chain that can be repaired in any location like
bum f Egypt.

 

[EricZ]

A chain under constant tension on both sides is a recipe for excessive wear and damage of both the chain, sprockets and bearings. A chain that is too loose can allow chain slap, excessive sprocket, chain, and bearing wear, tooth skip, and can allow the chain to come completely off the sprocket. Here are several sources that discuss proper roller chain tension:

http://www.diamondchain.com/frequently-asked-questions.php

http://www.ustsubaki.com/pdf/iandm_guide.pdf

Machinery's Handbook Version 26 (the master of all mechanical references)

 

[theMelvster6]

^^^[up][up]

 

[Petey]

In short
Idler Location: Approx. to that of factory, Roller chain tension is not as important as Belt tension, some thing to observe as well.
Chain slack Is better to be at the bottom of chain: Sounds great on paper but I do not have that option, With every Idler I have Tried slack Does remain greater at the top part of chain and sprocket, If you don't like it buy the 2000.00 dollar ebr kit.
Idler can be positioned for chain to rest on wheel with no torsion in spring, but then chain at top part is too loose, you may then create slack, to slap swing arm.
Tensioner now rests with torque loaded on spring where observation plays a part
Fully Relying on sprocket wear to indicate bearing wear, as well as chain wear. For the fearful, Bearings Do create very loud noises before they give way due to the release of grease.
2 to 3% chain slack is reference to stationary Idler
( like all those video's on you tube stating approx. one inch of slack.)
Chain will stretch, and adjustments will have to be made to compensate the distance.
From what I understand a new chain will stretch until broke in, then for the chain life will remain some what constant.
Annual bearing swap, is easier for me than 2000.00 for swing arm.
It seems that auto manufacturers, allow tension to be paced on serpentine belt, hope same holds true for motorcycle chains.

 

[EricZ]

Petey, you can't compare a belt to a chain when talking about tension. A serpentine belt has no teeth and relies strictly on friction to function which is why it needs to have a spring loaded tensioner.

The stock drive belt on the Buell is a toothed belt and requires there be no slack in the belt so the teeth always maintain proper engagement with the pulleys.

The stock rigid idler pulley for the belt maintains constant drive geometry for the majority of the suspension travel but not at the travel limits.

The Freespirits spring loaded belt tensioner is an attempt to maintain a constant belt tension throughout the swingarm travel since the length of the drive geometry changes at extreme swingarm travel positions, but it has very limited travel to prevent excessive slack in the belt during deceleration.

A chain, however, does not require or benefit from no slack. Your spring loaded tensioner is ok for a belt drive as long as the travel does not allow excessive slack. Your idea is a good one for a belt drive, but not a chain. Your setup would be "ok" for a chain if it had a very limited travel to prevent excessive chain slack but I don't see any travel limiting feature on your setup. The cantilever design will bend, either elastically or plastically, very easily under the bottom tension of the chain developed during hard deceleration. This combined with the travel from the spring setup is sure to give the chain lots of slack up top and really cause an issue.

 

[Theycallmecrash]

 

[theMelvster6]

It's okay to be wrong...that's how we learn...

 

[WIGGLE2]

It's okay to be wrong...that's how we learn...

Some people never do....To be that condescending to Eric who not only has the knowledge, but the SKILLS and experience to back it up is pretty pathetic. So be it.......Good luck...........

 

[mrlogix]

Crash- you crack me up

 

[jetlee]

Under hard deceleration, when the lower half of the chain goes under strong tension and forces your idler down/out/open/whatever...what are you doing to remedy the slack that is now on the upper part of the chain?

You don't use spring loaded tensioners on systems that see forces in two directions unless they have travel-limiting devices as Eric is pointing out.

To keep enough tension on the chain that the idler doesn't rotate out under hard decel, you would be causing a shit-ton of wear on your idler and chain during normal conditions. To avoid the wear, the idler tension is too light and will allow the bottom to straighten out and the top to go too slack during hard decel.

Trying to say this different ways so that maybe one of them makes sense.

Without a travel-limiting device, you cannot safely use a spring-loaded tensioner on drive systems that see forces in both directions.

 

[djs2k2]

Not hating, it may not work under all circumstances and I'm trying to be positive so I'll leave it at ( at least it does look good)! Live and learn.

 

[terrible]

Not to throw a curve here but I've used this brand of idler for over 20 years on my 78 bagger and have longer chain life and better sprocket ware.Now I know that this is a apples to lemons comparision but it works well for me on an HD.