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Hornet 600 - Sprocket-Hub Question

Discussion in 'Technical and Troubleshooting Torque' started by mattb, Dec 28, 2009.

  1. G'day All.

    The rear sprocket of my '98 Hornet 600 does not bolt straight onto the hub as per my other bikes, but bolts on to a part which looks to be the hub, but is separate (in teh way that a drum brake sits in the hub). I noticed yesterday that this part, on which the sprocket is bolted, has some play between it and the hub proper: sideways play of maybe one mm at most (i.e. it's not perfectly rigid as per my other bikes), but also play backwards and forwards of maybe three mm. The sprocket bolts are tight. Is this normal?

    I discovered it because I was noticing a grinding sound down there. This is at 900km since lubing the chain and leaving Melbourne, so I oiled it up before, rode it, and the sound's gone - a dry chain and dust was at fault (I was thinking a bearing). But, it's brought this movement to my attention (could have always been like this). Going for a ride through the Hay Plains tomorrow (Nyah-Balranald-Hay-Deniliquin-Melbourne - the long way home) in close to 40 degrees - don't want to be stranded out there!

  2. Sounds like your sprocket carrier bearing has gone. I'm not familiar with the Hornet as my Hondaphobia keeps me from examining such things in detail, but generally, what you'll find in that separate bit is a ball race of similar (but possibly not identical) size to your rear wheel bearings. There might be two, but all the ones I've seen inside have one. Provided there's not too much corrosion, it's a fairly easy job to pop it out and knock in a new one from your friendly local bearing supplier. Regardless of what it has as standard, a bearing with seals on both sides (2RS designation) is a good idea.

    There's a good chance that you cush drive rubbers will be shot as well. If they are, you'll be amazed at how much smoother your driveline is when they're replaced.
  3. Don't ride if you're getting noise from the rear wheel bearing; Loz did on his Hornet 900 and it cost him a passle of money.

    Agree with pat's assessment, btw, except I love my Honda :).
  4. Thanks guys. The sound seemed to have gone away after lubing the chain (did some tests around the block). Somebody asked a similar question about the sideways movement (as I say, very slight) on a Hornet Forum and the reply was that degree of movement was normal - the cush drive. I'll go for another test in a moment to check I'm certain that the sound was indeed the chain and not a bearing. My main concern now is that forward and backward (not sideways) movement of the sprocket carrier inside the hub. It has a very defined beginning and ending with 2-3mm distance - does your bike do that Hornet?
  5. When you say "forward and backward" movement, do you mean rotational? As in, the sprocket carrier will rotate forward or backward by that amount before coming up against something in the wheel?

    If so, I'd say that it's a normal amount on a bike with 10 year old cush drive rubbers in it.

    If you mean that it will move bodily from the back of the bike 3mm towards the front of the bike, that's huge and you've definitely lost your balls. Time for a new bearing.

    A little bit of side play is possible. 'Cos the carrier is (probably) only supported by a single bearing, it won't be super rigid, even if the bearing is good.

    If 'twere me, after I'd battled my fundamental idleness, I'd pull the back wheel so I could inspect the sprocket carrier bearing (rotating it by hand to feel for slack and roughness) and cush drive rubbers. I know it's a pain, but it's worth the peace of mind.
  6. Thanks Pat - yep, rotational. That's good to know (well, speculative knowledge at least). I think I'll go do my ride tomorrow as per planned. Had new tyres put on a week ago at a good shop, and they never mentioned anything untoward. I'm getting the head bearing replacement booked in when I get back to Melb, might include an inspection of all this in the job. I took the bike for a ride without my helmet just before (past the expensive new Nyah police station, confident there'd be no cops! (just as there wasn't when that guy bled to death out the front)), and even shut the engine down and coasted down a hill - no noise now, definitely no grinding. I realised that, while a desparate need for lube was the main issue, I had also put the Megacycle silencer in before leaving Melb, and was riding everywhere with a pillion, which would have exacerbated the sound for my ears. Best answer to most problem-noises on a bike is a loud pipe.