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My DRZ400 Front Sprocket turns really hard after chain and sprocket change.

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Today I decided to change the chain and sprocket on my bike however now the front sprocket turns really hard. The bike also moves in nuetral even if I have the clutch in. I simply removed the old front sprocket then added red locktight to the shaft splines and nut. Then I installed the new front sprocket with the raised side facing the motor. Finally, I installed the nut with the recessed part facing the motor. I tightend the nut by feel untill it felt nice an tight. If I loosen the nut then the sprocket will turn freely and the bike does not move in nuetral. What am I doing wrong?

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Today I decided to change the chain and sprocket on my bike however now the front sprocket turns really hard. The bike also moves in nuetral even if I have the clutch in. I simply removed the old front sprocket then added red locktight to the shaft splines and nut. Then I installed the new front sprocket with the raised side facing the motor. Finally, I installed the nut with the recessed part facing the motor. I tightend the nut by feel untill it felt nice an tight. If I loosen the nut then the sprocket will turn freely and the bike does not move in nuetral. What am I doing wrong?

what size sprocket? is the nut facing the right way? is the washer in the right place? how much loctite did you put in there? Is the sprocket fully seated over the grooves? 

picture or video? 

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One note I forgot to make, both simptoms are somewhat minor. The wheel only rotates when the bike is off the ground I dont notice any diffrance on the ground. The rear wheel can still be turned by hand in neutral although it does require some minor effort. Did not feel what the front sprocket was like before I took the bike apart. Is it normal for the front sprocket to turn hard?

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The word hard is misleading. If you have to struggle to move it then something is not right. You say when the nut is loosened it moves freely. Well to me it seems assembly is amiss. I need to look at a fiche pic and see if you are missing a spacer. The sprocket should turn the same tightened or loose. Not really the sprocket but the counter shaft. If when tight the CS binds then something is not assembled right. washers, spacers, sprocket, bend washer and nut need to be in right order otherwise it will bind on the case or outer bearing race and cause the friction. I will be back...

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I will be back...

 

I tightend the nut by feel untill it felt nice an tight.

 

While he's checking on that, you should probably go find a torque wrench.

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Read FAQ about the loose countershaft nut syndrome.  I have not looked recently but there used to be a long article on the how and wherefore, cause and effect of loose nut.  Was the CS nut loose when you removed it to change the sprocket?

 

If there is a difference in the resistance turning the countershaft in neutral nut tight vs nut loose you have the characteristic result of a collapsed internal second gear bushing.  DO NOT ride the motorcycle with the nut tight,  The result will be a locked up transmission.  Second gear will friction weld the the countershaft resulting in essentially being in 2 gears at once.

 

You have 2 choices.  Open up the motor and replace the countershaft second gear bushing.  Fairly inexpensive if you can do the work yourself. Or ride the motorcycle with the nut loose and deal with the potential problems that can/may occur as the result of that.  The worse being the nut comes off, the sprocket falls off and all the oil is pumped onto the rear tire contact patch.  Never good.

 

Do some research here, read up on the problem and think about how you want to proceed.

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Ok this is really strange. It works fine now. I rode my bike from the end of the driveway and into the garage. I then removed the nut and washer to take photos. I was going to remove the sproket but the locktight had already hardened and I dont have a puller right now so I reasembeled the bike. Now the sprocket moves freely and the bike does not seem to move in nuetral. Here is my theory. The bike had a larger aftermarket 16 tooth sprocket installed. I installed an aftermarket 15 tooth OEM style sprocket. I think the new sprocket was rubbing against the peice of rubber towrd the rear wheel causing it to turn hard. By running my bike from the end of the driveway to my garage (about 200ft) I believe the sprocket wore away at the rubber slightly causing it to rurn freely again. Does that make sense? Another note I did not originally install locktight because I did not know of the locktight fix. The sprocket still turned hard without the locktight so the locktight is not my issue. I have my sprocket installed just like in the diagram you refered me to jim. Here are the photos that were requested. How much do I tourque the nut to? 79lb ft?

Picture110_zpsd4cc0fdc.jpg

Picture109_zps861abbde.jpg

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Read FAQ about the loose countershaft nut syndrome.  I have not looked recently but there used to be a long article on the how and wherefore, cause and effect of loose nut.  Was the CS nut loose when you removed it to change the sprocket?

 

If there is a difference in the resistance turning the countershaft in neutral nut tight vs nut loose you have the characteristic result of a collapsed internal second gear bushing.  DO NOT ride the motorcycle with the nut tight,  The result will be a locked up transmission.  Second gear will friction weld the the countershaft resulting in essentially being in 2 gears at once.

 

You have 2 choices.  Open up the motor and replace the countershaft second gear bushing.  Fairly inexpensive if you can do the work yourself. Or ride the motorcycle with the nut loose and deal with the potential problems that can/may occur as the result of that.  The worse being the nut comes off, the sprocket falls off and all the oil is pumped onto the rear tire contact patch.  Never good.

 

Do some research here, read up on the problem and think about how you want to proceed.

 

 

 

Woah...thats scary stuff. The nut wasn't loose when I first removed the sprocket so hopefully this is not my problem.

Edited by coolpizzadude

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Yes that's why I asked what size sprocket you were using. The 16 tooth will rub until it cuts enough of that rubber out so it can rotate freely. But nobody answered any of my questions. Haha ..

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Yes that's why I asked what size sprocket you were using. The 16 tooth will rub until it cuts enough of that rubber out so it can rotate freely. But nobody answered any of my questions. Haha ..

I currently have a 15 tooth sprocket installed. I actually did answer your question above but maybe you missed it. It's all good. I think I am just going to put everything back together and run it unless somone thinks there is still a problem.

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Yes that's why I asked what size sprocket you were using. The 16 tooth will rub until it cuts enough of that rubber out so it can rotate freely. But nobody answered any of my questions. Haha ..

I currently have a 15 tooth sprocket installed. I actually did answer your question above but maybe you missed it. It's all good. I think I am just going to put everything back together and run it unless somone thinks there is still a problem.

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so everything is tight now? no looseness or play on that c/s nut? do ever doubt yourself on something.  the sprocket nut torque is 81 ft-lb use torque wrench not self calibrated hand  :naughty:

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Updated official Suzuki torque spec is 100 ft lb.  If there is still a problem, you will find out soon enough.

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Ok this is really strange. It works fine now. I rode my bike from the end of the driveway and into the garage. I then removed the nut and washer to take photos. I was going to remove the sproket but the locktight had already hardened and I dont have a puller right now so I reasembeled the bike. Now the sprocket moves freely and the bike does not seem to move in nuetral. Here is my theory. The bike had a larger aftermarket 16 tooth sprocket installed. I installed an aftermarket 15 tooth OEM style sprocket. I think the new sprocket was rubbing against the peice of rubber towrd the rear wheel causing it to turn hard. By running my bike from the end of the driveway to my garage (about 200ft) I believe the sprocket wore away at the rubber slightly causing it to rurn freely again. Does that make sense? Another note I did not originally install locktight because I did not know of the locktight fix. The sprocket still turned hard without the locktight so the locktight is not my issue. I have my sprocket installed just like in the diagram you refered me to jim. Here are the photos that were requested. How much do I tourque the nut to? 79lb ft?

Picture110_zpsd4cc0fdc.jpg

Picture109_zps861abbde.jpg

 

Your "sprocket theory" doesn't make sense, because the new one (15T) should be smaller in diameter than the old one (16T).

 

What I would do is:

 

  • loosen the countershaft/sprocket (C/S) nut and get the bike on a stand
  • remove the rear wheel and move the chain off the front sprocket (kind of push it forward and around the sprocket so it doesn't touch)
  • bike in neutral
  • rotate the C/S by hand, it should be smooth and only require a little bit force
  • torque the C/S nut to 105 ft-lbs (new Suzuki spec)
  • again move chain out of the way of the sprocket
  • recheck the rotation of the C/S, should be the same as before you torqued it

If everything checks out, definitely do the "loctite-fix".  If not, your options are as Noble posted.

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Your "sprocket theory" doesn't make sense, because the new one (15T) should be smaller in diameter than the old one (16T).

 

What I would do is:

 

  • loosen the countershaft/sprocket (C/S) nut and get the bike on a stand
  • remove the rear wheel and move the chain off the front sprocket (kind of push it forward and around the sprocket so it doesn't touch)
  • bike in neutral
  • rotate the C/S by hand, it should be smooth and only require a little bit force
  • torque the C/S nut to 105 ft-lbs (new Suzuki spec)
  • again move chain out of the way of the sprocket
  • recheck the rotation of the C/S, should be the same as before you torqued it

If everything checks out, definitely do the "loctite-fix".  If not, your options are as Noble posted.

 

Ditto .....

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the sprocket turning in neutral when the rear wheel is off the ground and engine running is normal. Pretty much all bikes do that, especially when the oil is cold

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Mike - Yes we understand that.  We are talking about more than oil drag when we say" turns hard".  The key factor is if the drag changes significantly with the nut tight  vs loose.  Tight being 80 to 100 ft lb. Loose being lightly seated to remove slop, say finger tight to 3 ft lb.

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I'd atleast put 85lb on the nut, spec might have change to 105, but some have broken the threads on the shaft. So somewhere between those points anyway.

Unfortunately the only way to really test what noble is speaking of, is after full torged, to remove chain and spin the front sprocket in neutral, it should turn very freely with your little finger, if it drags or a lot of resistance, that's very suspect to having the internal bushing issue..

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