I'd always assumed that the rear hub eccentric would (and should) just keep turning. Tried to adjust my JT chain today (never again - the bloody thing seems to be made of chocolate), to find that the eccentric won't tighten any further. If I back it off it turns just fine, until it appears to hit another hard stop in the other direction. Further inspection appears to suggest that these stops are in fact the rear brake caliper mount screws hitting the swing arm. Can anyone confirm that that is indeed the case? If so, it looks like I need to shorten or replace a chain with just 4,800 miles on it.
There is something not right there. The calliper bolts on mine are a good 1/2" away from the swinging arm. Are you sure the correct length of chain has been fitted? 102 links I believe.
Mine is very stiff to move, and that's 4K miles 18m old hardly seen wet or cold. And seems to be it moves easily then stiff then easily as if going through a cycle like when you turn an engine by hand. Elbow grease or you could take hub out: if been sued a lot could be a little tight and need greasing
I've never seen a stop on any eccentric hub I've worked on. If it is the caliper mounts hitting the swingarm all you can do is either shorten the chain or replace it with a decent DID or similar. What degrees of movement do you get from one end to the other?.
Silly question maybe, but the hub isn't spun round is it? Some have done that to lower the back end in the past, otherwise not sure if it would hit the mount??
If it's like the 848/1098 the pin locating the brake hanger is in a position which prevents the eccentric turning past about 8 o'clock - there is (on these) however an extra blind hole a bit further back which can be drilled & tapped to relocate the pin, don't know what model this photo's from but you can see the locating pin
I hope not: Ducati Glasgow supplied and fitted the chain, so I'd hope they'd have the nous not to do that. Turn-in is a little slow though and I've been trying to figure out why. Chain length is 110 links - I'm running a 42T rear, so that should be OK, although the lack of adjustment suggests that they should have gone to 108. It's also tightening in the right direction (anticlockwise, viewed from the left of the bike).
That is very helpful indeed: Haven't stripped mine down but Ducati doesn't usually change a design until (long) after it's been proven to be a pile of ordure and this seems perfectly OK. So the pin slides along the slot as the eccentric turns, until it hits the limit. All becomes clear. I'm thinking that I'm running into this as a combo of the dealer fitting the chain at 110 links (perfectly reasonably) and the bloody thing stretching ridiculously.
The standard length chain is in fact 108 links ( I looked it up because I couldn't remember) and the standard rear sprocket is 40 tooth. So with a 42t rear and a 110 link chain the adjuster should be in a similar position as it would be with the OEM fitments. I'd be very alarmed about a chain that needs so much adjustment in such a short amount of miles. I fitted a new DID chain at 34,600. The bike now has just under 40,000 on it and I think I've only had to adjust it once.
Yep, those were my conclusions too and, even without a Scottoiler I usually get 18-20k miles out of a chain, with just a few adjustments along the way.
Having fitted a 42t I can tell you the 110 link puts the bike back to roughly where it should be, it's the right length
Is it skyhook? Remember that needs adjustment in urban with ignition on and I found a bit clack as when the preload is added it makes chain tighter. If it is SH leave it in sport and see if still too slack
It's Ohlins/Ohlins SCU, and I've set one of the urban setting slots to mimic the stock settings in which it tells you to adjust the chain. So I don't think it's that. I'm in touch with JT to ask them if they can shed light on why their heavy duty x-ring chain is failing so quickly.
Found out what's been happening: JT got back to me very quickly, to say that they'd had a batch of chains that had gone out with no grease internally, due to a fault with their greasing machine. They're sending me a brand new chain as a replacement. With only 4800 miles gone, I'm hoping that the sprockets are OK. So the reason I was hitting the stop was indeed that the chain had stretched beyond the limits of the eccentric.
They've handled it very well, although I have to say that their QA system should be able to track every chain in a batch so that they could have done a recall on them, long ago. Makes me feel better, as I went with JT over my usual DID on Ducati Glasgow's recommendation and was feeling a little irked about it.
That's interesting, I'm guessing if it is the pin stopping the full rotation of the hub, all you short arses have to do to lower the back is slide the hub out to clear the pin, rotate the hub so its in the upper half of the casing and then slide the hub back in and relocate the carrier on the pin, the back will be lower and may be the calliper mount will be on a slightly different angle but I don't think it would affect it?
