Have i broken it??? Rear Sprocket...

[guest18]

Don't know what size of bearing, but someone here may be able to help? If it is still in one piece you should find a number stamped on the side eg 6402Z or similar (that is a random number by way of example!).
Take that number to a decent bike shop or bearing factor and they should be able to sell you a bearing to fit, as described earlier it should be possible to shim the bushes with scrap rubber or metal until you are able to replace them (assuming you choose to). The chain is definately *way* worn.
There is a risk that a very worn chain could break, or that the amount of play in everything could allow it to jump off the sprocket again, I can't, and I don't think anyone else can, predict if and when that may happen.
All I can say is you should fix it absolutely as soon as you can and ride gently meantime (and as little as necessary until it is fixed)
Good luck!
Smudge

[cloggy]

You've got to change the sprockets as well. A new chain may jump on worn sprockets, but worse than that worn sprockets will knacker a new chain superfast. Your rear sprocket is shagged . You should only just be able to lift the chain very slightly off the sprocket, not pull a bunch of links away as you have just done.

[guest27]

Are you taking a big risk.  Depends on how bad the chain is - when it is tensioned correctly - not sure what the slop should be on an SR - does it still lift off the front sprocket (or rear come to that - if so sounds a bit too much to me.  However if it is hanging i there and not ripping the rear sprocket off then... Well if you have an accident and it is caused by the chain breaking / coming off you may find that your insurance company are more than a little pissed off - but they would have to be reading here I guess.  If you are taking it steady it could / should be OK for a bit - but not too long.  I have seen chains with missing rollers in use (not mine) and know of someone who took links out of his chain because it was so worn it was too long.  Neither of these people came to grief.  Conversly I know of a GT750 Suzuki that spat off a fairly new chain - took a gouge out of the leathers of the lass on the back and a chunk out of the bridge they were passing.  Rider was lucky to get home not singing castrato.  More seriously chains coming off can and will destroy the engine cases, lock the rear wheel etc all of which is vvvvvv expensive and not a little life terminating at times.

Adjust it as best you can, go easy with the right hand - but dont make the engine lug, and get a new set in there ASAP.

Officially I guess the answer is no riding it until it is sorted.....

R

[guest7]

The most heartening thing about thsi forum is that nobody just shouted 'It's wankered'!

From my experience of cheap bike travel I'd say that a huge dousing of lubricant and an attempt to get it tensioned properly will help, especially if combined with a gentle throttle hand (and remember shutting off the thottle too quickly loads the chain too).

It's a great opportunity to hone those silky smooth riding skills

That sprocket movement is a bit worrying though.

I'm guessing that what you're finding is all the little things that were either knackered when it was parked up or have gone to shit quickly because the grease has dried up in bearings etc. After a bit of chasing around I'm sure you're going to have a little blinder of a bike though, so don't lose heart.

Are you confident about tensioning the chain? Forgive me if I sound patronising, but for a lot of younger riders with no supporting group of mates (as often seems the case these days) it's hard to pick up the skills needed to maintain a bike. Just ask Jethro about how many of his heavy walleted customers can adjust the chain of their megabucks sportsbikes.

Cheers
GC

[guest27]

I have often been confused about what is right and wrong for a correctly tensioned chain - and you will always get some one wiggle it and say - mmm too tight, too loose, wrong colour etc.  However reading this here chassis book by JR - he suggests a good way of making sure the chain is right for YOUR bike.  Disconnect the rear shock / shocks and with the bike supported raise the rear wheel untill the distance between the gear box sprocket and the rear sprocket are maximum.  adjust the rear wheel so that it is square (suggests taking the time to work out where this is and re grinding the tension marks or making up a set of check pieces etc - adjust the wheel until the slack is just out of the chain - as the wheel goes through this longest point the chain should just have all the slack taken out - any tightness at this point will pull the output shaft bearing and or the sprocket carrier bearing, any slack will be a waste of energy and excess slack else where.  Re connect the rear shock(s) and support the bike upright and in what ever condition you wish to check the chain - on centre stand, paddock stand, stood on its wheels - and measure the slack on the middle of the bottom run - this figure is the optimum chain slack for your bike.  If the chain can be lifted off the sprockets or is dragging on the floor, swing arm etc, a tensioner wheel is needed...

Alternativly look in the manual....  :-)
 
R

[boze]

ive fitted the new chain that came this morning and it appears to have helped a lot, the old chain had stretched so much it was about 4 inches longer than the new one!!!!

onepot: thanks for the concern but i have stripped and built about 4 or 5 (albeit 125 and 250cc) bikes and rode trials for a couple years when i was younger too, chain tensioning is cool but theres a few things on these old bikes that i have no idea about!!! like cush drives!!!!

Damo

[guest7]

I was in contact with the FSSCNOC (US thumper club) guys in the early 90s before I got around to setting up this here club. I have one of their newsletters here with reams on how they use ratchet straps to pull the wheel up to the correct height to adjust the chain (without the hassle of disconnecting the shocks). I used to think they were weird, but in retrospect it's probably worth doing at least once.

If you do it like that once then drop the swingarm back down then you can check the sort of freeplay you should be aiming for from then on. I've beenm meaning to do that on an XBR since, erm, the early 90s.

GC

[MrFluffy]

I tension the chain on my sp with someone sitting on the seat, or if Im working solo I lean over with my weight on it and check the chain tension like that,  as the arm is so short and it swings so much theres a great variance of chain length and I dont want to stress the gearbox shafts at the tight point if the inevitable tight spot makes its appearance (it seems theres mostly a tight spot unless the chains nearly new). It generally vandalizes chains quickly anyway, along with the cush drive, the rear sprocket nuts (I lockwire them now, but every so often one still snaps or breaks its lock tab), the support bearing for the rear brake plate (this is I believe a classic sp only malaise though) and the rear wheel spokes which tend to work loose every other year or so...

It might be a good time to check you dont have any loose spokes in the rear wheel if you have spoked wheels. If you find any a little loose, Id just zip tie them to their neighbour, but any bad or broken ones merits investigation...