84 250r clutch woes! Need advice badly

[ironchop]

How do you always find that stuff ironchop?? You always find information that I couldn't haha. But they're just saying to leave the nut loose to keep the two from binding together. Hard to believe that's considered to be proper when they give you a torque spec for that nut of 29-36 ft. pound.

I credit Google. I even find better search results for 3WW by googling.

The way I took it was that the gear that presses into the bottom of the outer basket came loose enough to make the whole assembly too tall and bound up that shaft.

I know the one on my 85 motor came loose too after I rebuilt the bottom end and I had to take it apart again to dead blow it back in there all the way. They are a pretty tight fit. I don't know if that's what's wrong with yours but worth a look.

I'd say if the manual gives a torque value, it's supposed to be torqued so I would ignore the "just leave it loose" crowd. Something is off a bit

Sent from my Z958 using Tapatalk

[wonderboy]

I've been reading and re-reading your original post and looking at the pictures and parts diagrams trying to understand exactly what should spin and what is coupled to what.

So, the clutch basket goes on first, and it is free spinning on the shaft, but is connected via gears to the crank. The clutch inner hub is splined to the shaft (the trans input shaft). So when the inner is locked up, it is because it it bound up against the basket (the two aren't free to spin separately).

To me it seems that something isn't right with that thrust washer in between the two (#14). Without the outer basket on the shaft, can you slide the clutch center hub on and see what it sits against? It must have to bottom out on something that is part of the shaft so that you can torque the nut. The center must be going too far back, or the basket is too far out.

I probably haven't told you anything you didn't already think, but those are the things I'd check: is clutch basket all the way down (towards the cases) and is the clutch center bottoming on the shaft like it should (check without the basket).

[ATCKevin]

Thanks ironchop, I will check out that gear.

wonderboy, the clutch center hub slides on the shaft, and #14 (thrust washer) goes against it. It appears to me that the center hub is sitting too far out on the shaft so when the thrust washer goes on and the nut is tightened, its tightening against the center hub instead of the shaft. The inside thrust washer (next to the bearing cages) is keeping the whole assembly sitting too far out on the shaft. And when I say "too far" I mean like .030 too far! This is so frustrating.

[HairyJR]

Kevin Wonderboy's write up couldn't have been written any better. The outer clutch hub/inner gear needs to spin freely at all times as the hub is driven by the crank and the kick starter idler gear. You don't know if the engine has been taken apart, is it possible the #16 thrust washers shown in the two different fish diagrams got exchanged. I think the thrust washer or the collar between needle bearings are too thick. When you pull on the main shaft is there any movement / float? The outer nut should be torqued against clutch center and the splined thrust washer and main shaft shoulder. Measure the thrust washer thickness? Hope I didn't repeat too much. Good luck.

"HJ"

[yaegerb]

Get a new clutch hub. It’s likely that the inner hub collar is worn letting the washer bind when the hub is torqued. The collar needs to protrude enough to keep the center washer from binding the basket and hub together.

[ATCKevin]

Hairy, I have been all the way through this engine. Bottom and top end. When I tore it apart for the the first time, I disassembled it and kept all pieces together for every component. With that being said, I know I did not get a washer mixed up with another one. When I went to remove the clutch assembly, the nut was very loose already. Which leads me to believe this is an existing issue and whoever was in this thing before me left it loose so it worked.

Yaegerb, I inspected the inner hub like you suggested. There is absolutely no wear on it that I can see. No marks or anything.

I did make some progress on this tonight though guys. I believe the inner thrust washer was in backwards? I put it together and tightened the nut down, not torqued to spec, but damn close. And now the inner hub rotates separately! It's amazing how tight the tolerances are to make sure those two pieces don't bind together.

[Dirtcrasher]

I dealt with a similar issue with an RM125 back in 1986.

What happens is when that clutch hub is tightened, the inner and outer hub are locked together. It still feels like the clutch is there, and you feel spring pressure, but the 2 hubs cannot separate and it makes you are crazy person; Well, it did for me anyway...

I was told to either leave that nut loose enough that the hubs spin freely, and use the lockwasher to hold the nut in place. The other fix was to use a thinner thrust washer behind that inner hub.

If you understand what has to happen with a clutch, you'll find the issue. I had a great clutch too before I rebuilt the crank.

I ended up doing just as I was told and it worked for the couple years I had he bike.

I suggest checking it out and if you do see that as an issue, I would buy a thinner thrust washer.

https://www.mcmaster.com/#thrust-washers/=1d2ohyl

[El Camexican]

Does the 84 R use a case gasket, or sealant? Wondering if a thinner or thicker gasket could have caused this?

[ATCKevin]

Dirtcrasher, I agree with a thinner thrust washer. I've looked into it already. I have the metal shop here at my school so I'm gonna try to see if they can make me one. The only problem I see with this is that there is barely any clearance between the inner hub/gear and the case already. A thinner washer is gonna make the gear sit even closer to the case. I'm unsure if a thinner washer that will keep the gear just off of the case might still not be thin enough for me to torque that nut down without binding the two clutch pieces together.

El Camexican, the 84 uses a gasket

[Dirtcrasher]

A thinner washer behind the inner clutch hub should allow you to tighten everything down, and they should spin freely without ANY plates installed, just tighten it up and see if they can both spin.

This can be an issue as small as .005 (5 thousandths), but you should be able to lock it down, and they should spin independently.

It's easy to check anyhow, just report back here and hopefully we can get you figured out...

I am not familiar with that particular design, IF a mainshaft had an extra or incorrect washer in it between the two ends of the shaft, that would create the same issue as it sucks in that mainshaft too far.

I know you were careful, but silly things screw us up all the time, lots of silly things! Hopefully your trans is back together correctly; But, it would probably shift great with an extra washer or a misplaced washer in the tranny,but it could be wrong.

Most mainshafts seem to have 1 to 2 mm's of side play/thrust when the cases are locked down.

[ATCKevin]

Dirtcrasher, I had the metal shop machine me a thinner washer. The nice thing about working in a tech school is having lots of options for all your needs. I had taken apart an old CX650 turbo bike (I think) last school year and kept all kinds of odd parts out of the engine. One of those parts was a thrust washer out off one of the trans shafts. Exact ID but just thicker. Did some simple math and gave the machine shop the measurements. Worked great. The nut torqued down, nothing is binding, and I now have a functioning clutch! If I ever have to get back inside that bottom end, I will certainly double check all my washers on the trans shafts. Thank you everyone for all of your help!

[Dirtcrasher]

Fantastic!! Glad it worked out!

[fabiodriven]

Nice job Steve!

[HairyJR]

Kevin glad you got it fixed. After having posted to this thread and some time to kill looked at a shop manual, love the challenge or chase, and all your parts are original, the only place a thrust washer/shim would be to affect the clutch side clearance is between the main shaft 1st gear shoulder and the left side case bearing, shouldn’t be there. Could they have replaced the case bearing and it was thicker and that's what has affected the stack thickness clearance dimension. You've done exactly what all good mechanic's do, figure out a way to correct the problem by machining another thrust shim. Now if someone else Google's " '84 clutch problem" and then it leads to this thread they still haven't got an answer as to why or at least the washer/shim thickness you made. What did the original washer measure and then the new washer/shim? These dimensions could lead those of us who have read this thread and thought about it try an determine possible cause. It’s my machinist background which leads me to ask these questions.

"HJ"