Engine runs but bike doesn't move in any gear

[Lawrence954]

On my last ride last fall, just half a block from the house, I heard a clunking sound and the bike stopped moving other than rolling slightly downhill. I'm ready to start working on it soon so I'm looking for suggestions. I figure it's either something with the clutch or maybe the driveshaft connection. Or something internal in the engine that I'm unware of although I do have the Honda Service Manual. It will shift into all the gears and the engine runs and revs and I can roll it while running. It would have been the first ride after an oil change if there's a clue there and yes, I added the oil.

 

[kerryb]

The only logical place to look first is the driveshaft connection at the rear of the engine. What troubles me is there is barely enough room to disconnect the driveshaft without moving the engine a little or removing the rear wheel, so the chances that that it just "fell off" are kinda slim. I would pull the boot back at the engine end of the drive shaft and try to turn the back wheel on the centerstand. That will show the tranny is working and what the driveshaft is doing. Let us know what you see.
I didn't see where you tell us what year?

 

[AApple]

IF the 1000 is like the 1100, it's possible the snap-ring that holds the front joint onto the engine has come off, and the shaft has slid back towards the diff. I would agree that the first thing to look at would be the driveshaft connection to the engine.

 

[AApple]

..maybe? So....just for future reference...the driveshaft did NOT fall off the diff...it slid back far enough to go past the splined portion of the diff shaft. I found this out AFTER dropping the engine back down to "fix" it. Anywho...got it bolted back up, dumped new oil in it, and tried to fire it up before complete reassembly. I did manage to get a fire started on some rags. As usual, I managed to get the damn ignition rotor back on 180° out...AGAIN. Since I've managed to do that 3..4 times now, I learned the last time the easiest way to correct that is to simply swap the wiring on the ignition coils...not the plug wires, but the actual wiring to the +/- part of the coils. Much quicker than doing anything else. After that, I hit the start button, annnnd....EUREEKA! Fired right up no problem. I called it quits for the day. I'll try my best to get it all put back together next weekend, tho there is another issue I need to ponder. More on that later.

 

[Lawrence954]

The only logical place to look first is the driveshaft connection at the rear of the engine. What troubles me is there is barely enough room to disconnect the driveshaft without moving the engine a little or removing the rear wheel, so the chances that that it just "fell off" are kinda slim. I would pull the boot back at the engine end of the drive shaft and try to turn the back wheel on the centerstand. That will show the tranny is working and what the driveshaft is doing. Let us know what you see.
I didn't see where you tell us what year?

It's 1975 with 46,000 miles. I've had it since 1996 when my dad gave it to me. He bought it in 1975.

 

[Lawrence954]

On a stand, in neutral, the U joint doesn't move when I rotate the rear wheel. When in gear, that joint doesn't move but the rear wheel will still rotate. So it sound like the problem is not in the engine. I checked the hub and it is full of lube.

 

[Two85s]

Spline on the rear wheel in striped. Pull the tire.

 

[AApple]

... When in gear, that joint doesn't move but the rear wheel will still rotate...

So it(u-joint) does not move with the engine running, and in gear, clutch out? If that is so, then your issue is INSIDE the engine. If the joint/shaft moved with the engine running and in gear, your problem would be diff related. Two85s makes a good pint too...it could be the splines on the rear wheel drive hub, or diff splines. Rear hub splines

 

[Lawrence954]

So it(u-joint) does not move with the engine running, and in gear, clutch out? If that is so, then your issue is INSIDE the engine. If the joint/shaft moved with the engine running and in gear, your problem would be diff related. Two85s makes a good pint too...it could be the splines on the rear wheel drive hub, or diff splines. Rear hub splines

I didn't check the U joint with the engine running. In neutral the U joint spins, in gear it doesn't but the rear wheel spins in gear or in neutral.

 

[mcgovern61]

I am missing something. The rear wheel spins in gear (on the centerstand), but the U joint doesn't spin? Maybe for clarification:

*The rear wheel can be moved (free wheel) whether the engine is in gear or in neutral, but the U joint does not spin when in gear (like it is stuck?)
*With the engine off and in neutral, can you spin the shaft at the U joint?
*With the engine off, but in gear, is the U joint able to be moved or is it stuck solid? In this condition, does the rear wheel still free wheel?
*If at any point, the rear wheel can be moved and the U joint/shaft cannot be moved, the wheel is obviously disconnected from the shaft. That can happen if the rear splines failed in the pumpkin (although I would expect you would hear grinding) or the shaft may have cracked and split.

Any time you spin the rear wheel, the shaft/U joint should always spin even if the engine is out of the bike. The U joint can slip back if the snap ring broke, yet still look like it is attached. It doesn't take much for the U joint to slide back and disengage from the shaft splines.

 

[Lawrence954]

Well today I got smart and pulled the boot off the swingarm side. It was then that I discovered that both sides of the U joint are destroyed. So it looks like I'll need a drive shaft and the part that goes on the splined shaft coming from the engine. Thanks for the suggestions.

 

[Lawrence954]

After consulting the manual, I see that everything between the engine and the hub except the circlip are part of the drive shaft. I enjoy interacting with this group but it's something that I haven't done in a while. Your suggestions and advice are always welcome.

 

[mcgovern61]

I am glad you found the problem. I am sorry to hear the shaft needs to be replaced.

 

[chilidawg]

Damn, I just trashed a real good motor frame and final drive, because nobody wanted it, yeah it'd all done 140K, but still, it woulda fixed you up.

 

[Lawrence954]

Here's what was left of the U-joint. I found one and got it back on the road this afternoon but working with the cir-clips and boot about used up all my patience.