I desperately need your help. I've searched and searched for this answer and it was almost answered but the original poster never followed up. I have an 87 lt80. I've rebuilt 90% of this bike for my son. The rear clutch is my issue. Bike fires up great but only if the rear end is off the ground. It's like there is no neutral. If I hit the break or stop the wheels from moving the bike bogs down and will stall out. I've followed the transmission 2 diagram to put all the plates back on correctly but the clutch drum will not spin freely. If I loosen the nut it works great, well the tires wont turn, but other than that the engine revs great. Once I tighten the nut the tires spin like I'm opening th trottel. I'm at a loss on what to do. Do the plates need to be greased? Surely the drum is not greased. Right? any help would be appreciated. Thank you in advance.

 

Welcome to the forums.
There has to be something missing/wrong in the rear clutch. The bearings in the post are in place and OK? Is the post going all the way down?
I suspect a twisted roller in the front clutch. It's not supposed to drive at idle.

 

Thanks for the reply. The two bearings on the rear are new and the clutch unit is all the way down to the gear box. I have not touched the front clutch so I will give that a try. My friend has one for his son and it will roll in reverse with engine running so clearly mine is goofed up somewhere. I don't fully understand these clutches and did not think no the front would effect the rear like this. Hopefully this does it.

 

I suspect you'll need some parts (rollers/clutch plate if not everything). You'll prolly find rock hard grease. That stops the rollers from doing their job and usually ruins the hub.
Let us know what it looks like in there.
FYI: the rollers will flip when the clutch hub is removed. Unless one is mashed in a tract, you won't be able to tell if they were flipped.
Rear: one thing I thought of, are you sure the splines are aligned when you put the umbrella (thing below the nut) on? You have the correct nut right?

 

I removed the front clutch this morning and grease ozzed out from the back side. Not sure if this is normal or not. Removed one of the three screws and the others stipped. Will get them removed tonight. As for the rear, the umbrella is aligned properly with the splines. As for the nut, not sure if it is correct. I mean, all nuts are created equal, right. The nut fits with ease so I know the thread is correct. When I got the ATV all the mechanical parts were in a box, so I followed diagrams and orderd most of the parts from ebay or babbits.com. With the front clutch removed I will see if the tires roll with little friction. When everything is connected the rear are very hard to move and sometimes it will turn the front fly wheel and I can hear the piston move up and down down the cylinder. Not normal. The rear clutch pads are pretty thin and will need to be replaced eventually, but I don't think that would be the cause of my current issues. I'll update what I find when I disassemble the front clutch.

 

The rear nut is not a normal nut. It should have a step in it (portion not threaded).

 

Just looked that up and its interesting. Definetely do not have the correct nut. Can I ask, what the point is to that specific nut? Can that really be the cause of the gears running at idle? What direction does the nut get installed? I'll order one as its less that 5 bucks. Seriously can't thank you enough for your responses.

 

The nut matters because it goes over the splined shaft when tightened. You're sure the umbrella is going on the splines?
I'd like to dbl check on the bearings on the post. The small bearing is installed with the clip that hold it in place, correct? The bottom bearing is pressed in the post far enough?
With all that correct and slid on the shaft, the splined hub piece is next. That piece should not contact the post clutch assembly.

 

Here is the assembly.




Small bearing is pressure fitted and has the snap ring in place.



Bottom bearing and it is flush with bottom.





Small gap in between.



First friction plate



Drum



Second friction plate





Not sure if this is correct way to put this on looks right from other pictures I've seen.



Here is the umbrella piece. You can see the spines coming through.

Until I get the specialized nut I put a washer then a regular 10m nut to keep it off the spines.

Is this all correct?

 

The picture does give the amount of grease in there justice.



Clearly this is not the way this should look. However, do you believe the issue still lies in the rear clutch? When I get new rollers do I grease them first or reassemble dry? One thing I notices was then the belt on the rear and the wheels are moving, the rear clutch drive sheave also moves. Basically the entire rear clutch assembly moves as one piece. Normal?