| Author | Message | ||
     Drfuyutsuki |
Is it possible and in the end worth putting an idler pully on a tube frame (IE my 97 S1)? | ||
| Buelliedan |
no its not possible because the tube frame swinarm does not swing in a perfect arc. there would be spots that had more tension than others making it useless, dangerous. possible both. | ||
| Drfuyutsuki |
Thanks Dan, was just an idle (no pun intended) thought I had when looking at a picture of a xb. | ||
| Djkaplan |
All conventional swingarms swing in a perfect arc. It could be done, but you'd have to figure out exactly where the idler needed to be to maintain constant belt tension throughout the swingarm's range of motion, and you'd have to do away with the belt adjustments at the end of the swingarm so the location of the axle would never vary. As to whether it would be worth it, that would be up to you. Interestingly, Husqvarna used a similar concept (except with rubbing blocks and not an idler) on their motorcycles in the late 70's to maintain near constant chain slack without a spring loaded tensioner. | ||
| Buelliedan |
DJ, Are you sure Buells swingarms swing in a perfect arc? Have you ever taken your shock off and tried? You might be in for a surprise! | ||
| Whodom |
The other problem is the belt on tube framers would probably NOT like being run over an idler. Several articles have mentioned that it took a lot of effort to develop a toothed belt for the XB's that could be flexed in both directions. The tube frame belt was not designed to do this and would probably fail much earlier than normal. | ||
| Djkaplan |
Yes, I am. The swingarm can do nothing but swing in a perfect arc. The belt changes tension because the drive pulley is not perfectly centered on the swingarm's axis of rotation. This is the also the case with the XB and all motorcycles with chain or belt drives. I can only think of one motorcycle that avoided this by having a drive sprocket on the swingarm shaft - an old works Honda motocross bike from the mid 70's. | ||
| Buelliedan |
DJ, Now you are playing with words. When I say swingarm I meant the whole setup to include all components attched to it like the drive pulley. So I should have said the belt does not swing in a perfect arc. No matter the wording the simple facts is that the belt does not swing in a perfect arc making a tensioner unusable on a tube frame. | ||
| Djkaplan |
I'm not playing with words, just stating facts. Dan, the belt does not swing in a perfect arc on an XB(using your terminology) either, - meaning, without an idler, the belt on an XB changes tension as the swingarm goes through it's range of motion. Think about it. | ||
| Blake |
XB's and Tube Framers share similar geometric relations insofar as swingarm and drive/driven sprocket and belt locations go. I gotta agree with DJ. Remove the idler pulley from an XB's final drive and you'll have the same situation as on a Tube Framer. The belt goes slack when rear suspension is unloaded and tightens more with more rear suspension loading (compression). When an XB rear suspension is fully loaded (compressed), I'd bet that the belt is barely riding against the idler pulley. | ||
| Bomber |
the cruical thing about idler pulleys (well, one of em, anyways) is the placement -- tough to get it in the right place on a tuber -- not impossible, but it's cramped quaters in there -- I remember rearing the piece in Fuell re: the idler pulley on the XB platform -- seems it took a lot of computer time and minds far better than mine to figurethe whole thing out -- complex issue, with many variables acting on the rear suspension the was a product once upon a time (80s) that consisted of two idler sprockets (chain drive scoots) -- one directly above, and one directly below the swingarm pivot poitn -- idea was to isolate the affects of the engine from the rear suspension -- | ||
| Djkaplan |
You're thinking about the AMP Link... http://www.amp-research.com/media/index.asp?cat=6 | ||
| Bomber |
DJ -- right you are, but, boy o boy, has that product moved uptown since the last time I saw it! | ||
| Road_thing |
Ain't that the truth. I don't remember the "old" version having carbon fiber on it. In fact, I don't think I'd even heard of carbon fiber when that thing first came out! rt | ||
| Bud |
just a picture i saw on the web  |
