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[Melb] '98 Xj900 help

Discussion in 'Technical and Troubleshooting Torque' started by quadfour, Feb 10, 2011.

  1. Hey everyone. Recently got myself and old '98 XJ900 with about 137k which needs a little TLC.

    First things first, there's a knock at idle in the engine. Sounds like it's coming from whatever chain turns the alternator. No idea what that is as I don't have a manual as yet. The knock is more pronounced when cold, but is still there when hot. I've used a makeshift stethoscope ( twistable screwdriver ) to have a listen. Sound comes right up and through the alternator. I took the alternator out and everything seemed nice and tight. I've seen people make reference to a starter chain which could be the one... It's in the general vicinity, and it would make sense to have one chain for the alternator and starter. But then again, I just don't know. Otherwise the thing seems to run alright, sounds nice all through the rev range.

    Anyway, point of this post is trying to find a reputable shop happy to take a look. I've given Everything Two Wheels a call, and they're not really interested in taking on the job (due to age + miles). I've called Intyre too, but their engine mechanic is going on leave for a while. I'm not overly keen on speaking to City Yamaha as I've had issues with em before.

    Anyone want to name a place or have any suggestions on where I can take it? I'd prefer not to work on it myself as I just don't have room, so it'd be a right PITA. :)
  2. Like I said on the phone you could easily put a couple of grand into rebuilding the motor on this bike.........and at the end of it you'll still have a POS 137,000k 13 year old bike. I've seen it happen many a time before where guys start spending money to fix up an old bike and then once you start you cant' stop. Before you know it your wallet will be empty.

    The bike shops around Melbourne are pretty keen to move stock on due to the past couple of years being very slow in the bike industry and there are some pretty good bargains to be had (even on second hand bikes). Put the money towards something better or you'll end up spending a heap of money and still wont have a nice bike at the end.
  3. Jeeeeezuz, listen to the man.

    If you bought yourself a project bike the idea is to source the parts and do the work yourself, you know, for the love of it. You can get a good cheap bike from the auctions if you know what you're doing and invest in it so it's got some value, but that's not for the faint of heart. But there is no way you can turn a turd into a gold nugget, no matter how much you polish it.

    I've owned one these until it was ridden into the ground, my only hope is that you don't now own it. You can tell because i welded the front sprocket on and it was written off twice. Have fun now.
  4. ...wait!!! sorry, mine was a 600, you're good to go.
  5. Bugger. Hope I am not riding your sloppy seconds, Chef

    Actually replaced the front sprocket recently, It was a bit of a bugger to remove but it wasn't welded. Pheww!
  6. True words are true.

    Had such plans for this bike. It's a hell of alot more comfortable than my VFR for long runs. And I'd know... been around Oz (almost the whole thing) on the VFR already! :p

    If indeed the problem is down in the guts, then you're right. I should cut my losses there. ( Or do the work myself where labor is free )

    Problem is, I just don't know what the issue is right now. After some more thought into it this evening, doesn't really fit to be a timing chain as the thing runs sweet in the low and top end. The noise does originate near the crank, but comes all the way through the alternator quite distinctively.

    I've found some schematics for the engine, but they don't really show what drives the alternator. I will have another play and see what else I can learn if necessary.
  7. I have a mate who bought one of those second hand in '84, he's still got it. The speedo died at about 240,000km and that was 10 years ago, who knows whats on it now. It still goes, pulls like a train and gets used daily. Only problems have been leaky fuel tank and rusted mufflers. He checks the valve clearance every few years and has had to adjust them once. Its been making a noise like you describe for years, just buy some ear plugs and ride it!
    I hate to use the cliche "its bulletproof", but apparently there aren't too many around now because the ADF are buying them and melting them down to use as tank armour.
  8. Before panicking about major mechanical work, get the carbs balanced. I'm not intimately familiar with the XJ but I've known other fours where carb imbalance seemed to set up all sorts of odd resonances that sounded like bearings on the way out.
  9. Is this a Diversion? I've had a few of these, both the early XJ900F and the Divi and they all knock a bit. A carb balance really helps. Both these engines are good for at least 250000. I can recommend Simon in Melbourne at Yarra City Motorcycles
  10. What a day! PatB & rider5, you're right on the money.

    One of the fellas on here was kind enough to send me a manual until the Haynes arrives. Can't thank him enough, definitely owe him a beer :D

    I used that manual to adjust the idle and sync up the carbies. They were way out in both idle ( was out like 4 turns on the pilot screw ), and carbies 3 & 4 were doin most of the work.

    Tried a vacuum gauge before figuring out that it needed a dampener to get a sensible reading, so ended up building my own 4-carbie sync rig with some instructions from another forum using plastic tubing and some ATF. Worked a treat, was able to get em all fairly close.

    The thing still idles semi-roughly, hops around a ~200rpm range from 900-1100 rpm, but otherwise sounds sweet. The knock at idle which was there is gone, and still sounds nice up in the rev range. I'll give her a fire up tomorrow when stone cold and double check, but I don't expect anything out of the ordinary.

    Oh, I didn't end up checking the timing. Not sure where I've placed my timing light! Bike sounds sweet enough though, doubt it's out. But if anyone has a timing light I could borrow momentarily, I would double-check.