Front Sprocket Replacement

Read owner's manual and familiarize your self where the parts of your bike are located.
 
Lakeview, in the time it took you to type that "answer", you could have actually helped. Or done something else useful.

I would think y'all would know what I was talking about. But for those who don't know, that this motorcycle is chain driven. The final drive chain moves the bike forward by connecting the gearbox to the rear wheel sprocket with a chain. I am trying to remove the gearbox sprocket.

I would appreciate any actual help from anyone else.
 
Take the left side cover off, and there it is!

Make sure to check the orientation of the nut(big muther fucker! I think its a 32!), it has a recess that has to point inwards(if I remember correctly).

Best to replace both front and rear sprockets as to reduce premature wear.
 
Thank you Airwolfie. Let me elaborate.

I have been trying to loosen the nut without much success.

The Haynes Manual suggest removing the cylinder heads and pistons and locking the crankshaft by putting a bar through. Seems a bit extreme to change the chain and sprockets.

Just wondering if anyone had a trick here.
 
Ah ok. Stick the bike in second gear, and try again. If that doesn't work, try some heat on it. If that doesn't work, I don't know...................
 
I sit on the bike and apply the rear brake as I loosen the nut (bike in gear as well). I tighten it back up the same way. You need to make it really tight if you don't want an oil leak, like 90 ft/lbs tight.
 
jmcookesq said:
Lakeview, in the time it took you to type that "answer", you could have actually helped. Or done something else useful.

I would think y'all would know what I was talking about. But for those who don't know, that this motorcycle is chain driven. The final drive chain moves the bike forward by connecting the gearbox to the rear wheel sprocket with a chain. I am trying to remove the gearbox sprocket.

I would appreciate any actual help from anyone else.
Click to expand...

Hi Jim,
well, I dunno.
My first thought on reading your first post was to think "WTF? My old Britbikes had a front sprocket but the XS650 primary reduction is a pair of gears?"
Had you said "transmission sprocket" the confusion would have been less.
But hey! There's no middle ground with removing those bastards. Once you flatten out the nut's locking tab the nut either spins off by hand or it's a right swine to move.
Guess yours didn't spin off.
A 36mm impact socket on a good quality air impact wrench and 120 psi air should shift it.
If it don't do it without locking the drive train and the hammer handle through the rear wheel spokes don't work there's an old bodgers trick to jam the motor without tearing it down.
Remove a spark plug, feed a length of rope down the plughole with enough to remove it still hanging out and bring the piston up on compression stroke so the wad of rope locks the engine.
 
JMCOOK
You can go to any garage that has air tools and give them a couple bucks to loosen it. There is a washer on there also that has to be bent back.
Like everyone said CHAIN MUST BE ON and put it in gear have someone hold rear brake and you are pushing towards front of bike. LEFTY LOOSY RIGHTY TIGHTY
If you have problems you can ALWAYS get me at DADDYGCYCLES@YAHOO.COM
Rich
 
Per 5Twins recommendation... I sat on my bike, in gear with my foot on the brake, and had my breaker bar pointing straight up. Inserted over my breaker bar was a four foot long piece of iron pipe I use for occasions like these. One forward slightly sharp rap on that pipe with the palm of my hand was all it took. Very easy. You can buy a pipe like mine at a big box store for just a few bucks. Having one does come in handy. I haven't needed an air impact for anything yet. Although I would think that if there were a space constraint, one would come in handy.
 
When putting the sprocket tab washer and nut back on you need to be very careful that the inner "teeth" on the tab washer stay lined up on the matching shaft teeth. Often that washer is pretty boogered up. I'm cheap so flatten and file the washer as needed so it goes on and stays put. As mentioned above the nut must be replaced with the recess facing the engine. And put on TIGHT. I have found "as installed by the factory" nuts that were loose. (79, 5000 original miles) If the nut is loose, the output shaft leaks around the seal.
 
Well, I don't think it's actually the seal that's leaking. The oil runs out between the shaft and the sleeve the seal works against. Having the nut really tight prevents this. It seals the back of the sprocket to the sleeve and the back end of the sleeve to an inner bearing race in the motor. You have two metal to metal points you're trying to seal so the nut must be very tight.
 
I have fitted my front sprocket with thread lock clean the threads well with thiners apply thread lock, the blue or green, dont use stuff that been sitting in the garage for years. buy some fresh stuff, torque to spec you should be fine.
My engine builder said that he has done this on all his rebuilds about 90 of them without issue and he build race engine for the xs650. Just to reasure you ...

All the best
 
No tabbed washer :yikes:...........may be ok for a race bike if it gets checked every day before and after racing but for the general public who are lucky to change and check the oil as often as should be done, a tabbed washer is essential.

Safety is the issue. Just thinking of a front sprocket coming off at 60-80mph................
 

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