Yamaha XT600 Front Sprocket Removal

The bike is a 1991 XT600EB dual sport. I can't find a manual­ for it
anywhere seeing as Clymer left off at 1989. I have the new
s­prockets for it but need to know which way the front sprocket comes
o­ff. Is it standard or reverse (left or right) threads? Also, does
anyo­ne know how much torque it's put on with? And what's the best
method for­ holding the motor from cranking while I'm trying to turn
the nut? TI­A
If anyone knows where I can get a manual for the bike that w­ould be a
great help too!

 

front sprocket comes o­ff. Is it standard or reverse (left or right)
threads?

I have never seen a reverse threaded sprocket nut on a motorcycle. One
would also expect the nut that holds the alternator rotor onto the end
of the crankshaft to be reverse threaded, but it's not...

Probably about 50 ft-pounds...

I'm trying to turn the nut?

You might have somebody step on the rear brake pedal while you break
the nut loose and tighten it. If that doesn't work, park the motorcycle
with the front wheel against an immovable object, put the transmission
into 5th gear and loosen the nut. Park the rear wheel against something
when you tighten the nut...

When I change countershaft sprockets on bikes that have cast aluminum
wheels, I stick a piece of wood through the spokes so the hweel can't
turn when the wood hits the swing arm...

But you will probably bend some wire spokes if you try that with your
dualsport....

 

Ok. I will give your suggestions a try. I ask because late in the
summer I tried getting the countershaft sprocket off - I had it in 1st
gear, wood thru the spokes, one hand on the rear brake while trying to
break it free with the other hand. If I recall correctly I had a
cheater bar on the end of the ratchet as well. I may have been a little
timid with it though too so as not to break or snap anything or bend
any spokes as you say. What's the reason for putting it into 5th gear
while turning the nut? Thanks again.

 

Is there a locker on the nut? Don't do the wood thru the spokes as
that's hard on the wheel. Use KK's foot on brake only (get a helper to
really mash down if necessary). If it's frozen, then use AeroKroil.

 

No, no locker on the nut other than a cotter pin. I've never heard of
AeroKroil. Where is it available?
Btw, would Godzilla's foot be ok? I misplaced KK's number! Thanks!

 

Theoretically, it keeps the wrench from using a lower gear's greater
torque multiplication to easily turn the engine over against
compression...

 

Industrial supply places near me carry it. You can do a a Web search or
make your own local calls. It is a penetrating oil that makes WD40 look
like sludge. I spray it on exhaust systems which are years old and they
just come apart w/o tools after about a .5 hr soak.

This s/b NOT that big a deal.

 

<snip>

Strange. What sort of strange beast is a XT600EB? What
market is it sold on?
The reason I'm asking is that all XT600 I've seen (in Sweden)
have had a folding washer to lock the countershaft sprocket.
Often this will not work and a drop of Loktite is called for
and that does not make it easier to loosen it ;-)

A cotter pin sounds a bit rattely for this application.

 

If this is the transmission output sprocket, you'd want the
bike in low gear to help keep the engine from cranking.

 

Try bumpstarting a bike in low gear and top gear. See which one
turns the engine more easily. You want low gear to keep the wrench
from turning the engine over. This is assuming you're working
on the output end of the transmission.

 

Back in the old days of run-and-bump starts at the beginning of
roadraces, the riders would put their big singles into *second* gear,
as they couldn't push against first gear with their dragging clutches
and the heavy weight oil in the separate tranny...

 

Point being that top gear is the one which turns the engine over
most easily while low gear turns it over least easily. If you
want to use the engine to help restrain transmission output,
the bike should be in low gear.

 

You will get the most crankshaft motion if you put the tranny into low
gear. When you're breaking the nut loose, it doesn't matter much if the
crankshaft turns and tightens up the cam chain. An automatic tensioner
might even take up the slack in the back of the chain...

But re-tightening the nut while the tranny is in gear turns the engine
backwards and that might jam the cam chain against the sprockets...

You might even jump a cam sprocket tooth if your cam chain tensioner
hasn't been taking up the slack...

 

was attempting to loosed the front sprocket nut... it snapped like a
tooth-pick.

You may need something stronger than an old broomstick. You may need a
2x4, if you can slide one between the spokes and the swing arm...

Front sprocket on a Bandit is probably torqued to 80~100 ft.lbs., so
with about a 3:1 final drive reduction, the force against the wood is
about 240~300 pounds...

I used an old steel car tire iron once, to stop the rear wheel from
turning on a GS-1100. Before I heard my torque wrench click, the tire
iron bent...

But the OP wanted to break the nut loose on a Yamaha dualsport bike.
The torque on the nut on that bike is probably only about 50 ft.lbs.,
so an old broomstick might just be strong enough...

 

How about some air tools!

 

I don't have the exact figure but I assure you that it's a bit more than
that, I've done it a few times. I used my torque wrench when loosening
the nut just because it has a long handle and would give me some
leverage.
Standing on the rear brake lever, I'd reach over the bike to use the
wrench. Sometimes it's an advantage to be a bit tall.