Tight countershaft

[yeomans]

Hey all,
I'm in the process of mating my cases back together after a crank rebuild.
I have the gears, forks and drum in the case. Gears are in neutral and everything spins freely as it sits.
When the other case halve is dropped on everything still spins freely like it should.
The problem arises once the case bolts around the countershaft begin to tighten and the shaft locks in place, and won't rotate freely any more.
I let the pressure off the bolts and the shaft once again spins freely.
Two things go through my head:
The  countershaft bearing isn't completely driven in square to the case or,
I had the oil drain re welded and there might be some warpage of the case?
Anyone experience anything similar before?

Any thoughts?

[Motorrad]

Did you forget the one shim in the trans that likes to fall off?

[yeomans]

I think everything is in place, Been looking through the manual and online. The 88 models on have a washer on the mainshaft that the earlier 86-87 motors don't seem to have.
Kinda stumped on this one. Is there another shim you speak of?
As soon as I tighten the last few bolts in the case around the countershaft it seems to lock in place.
It's literally the difference of 2-3 turns on the bolts and having the shaft rotating freely and being locked in place.

[yeomans]

I haven't been able to trace any image or part number for a shim within the 86 crankcase.
The manual says however that when splitting the crankcase be aware of any possible shims between the transmission and the left crankcase. But doesn't show a photo or a exploded diagram with any shim.
Anybody know of any shims that were in the 86 crankcase?
Starting to believe this might be my issue.

[Motorrad]

Hmm. Let me think. I didn't realize we were playing with an 86.

[yeomans]

It would be different if I took the engine apart originally, but this engine was all in parts when I first received it, and I haven't found any shims.

[tobys 2 strokes]

If you were missing a shim that was needed it would be losser not tighter its probably your out put bearing not seated all the way.
I had that happen on my 97 that I have in me T4. but I had done a bunch of welding repairs to the cases and had to lap them to the point that it tightened the clearance up and had to remove some from that steel bushing in the cases to make it spin.

[yeomans]

I had re seated the bearing last night just to take that off the list of possibilities.
But it was still tight when I re sealed the cases.
I had noticed a few very light scrape marks on the inside of the right case where the countershaft sits which made me wonder if it was a shim that was missing.
I do hear what your saying though about the case being loose if I was missing the shim

[Rick james]

I had the same problem reassembling the cases on my 93. Tried it 4or 5 times, and as soon as I tighten the bolts, it locks up as well. I'm confident that I put it back together with all of the parts, as I'm using a service manual, and I took it apart extremely carefully, noting positions of everything. I even tried freezing the crank with dry ice, it dropped right in and was still frosty after an hour of sitting in the cases. Been waiting for some $$ to come through to get it done professiknally, but I've been hoping someone on here knows what it is. Good luck, let me know if you figure it out!

[Motorrad]

Mix up the shift fork shafts??

Is the primary side assembled yet?

[Rick james]

I believe the shift fork shafts are different enough lengthwise to where the cases don't come close to mating if you swap them. Plus the longer one has the two forks on it, although its been a few months since I've messed with it, so I'm going off of memory on this. I assembled it dry and without a crank a few times before I tried sealing it up, and it was shifting through the gears by hand like a champ, but after dropping the crank in and applying some torque to the bolts, I get the same problem. Crank is hard to spin, countershaft seems locked, it's impossible to turn by hand. Tried tapping the ends of the crank, as I've seen elsewhere that it needs to be relieved, but a few solid taps didn't change it and I didn't want to beat it too badly.

[sandblaster]

Did you use your old crank or a rebuilt one?

[Rick james]

Old crank. Bearings spun OK, but I'm pretty confident that's what the problem is. I think I dislodged one slightly during the split. I out feeler gauges under them and the seemed equal, but at this point I'm just saving for all new bearings and shift forks and a pro rebuild job. Got a good quote from pissonault, but there's a local guy who also quoted me a lower price and came with outstanding recommendations, so I'm going to go through him.

[motopunk]

did you replaced also parts of the transmission?? or maybe it is not the original countershaft of this motor... like you said, engine was in parts... possible that the shaft  is from another engine or a later year .. would look the same, but could be minimal diferent

i had the same problem with an 85 kx 250 engine last year... a good friend bought it in parts and i should rebuild it for him... you get quite crazy, when after 5th try with complete reassembeling all parts to right direction , the countershaft would be still clamped by the engine cases . i had a 86 tranny laying in my spares. swapped the countershafts and it worked...   later we found out that the coutershaft in the 85 parts-engine was a from a 87 engine..  now it sits in my spares for my 87..  
for me it looked that the pre owner had mixed it by taking parts out... sometimes all looks good, but little things can make the big effects...
 and there is always a reason, why selling an engine in parts and not assembled..

I think everything is in place, Been looking through the manual and online. The 88 models on have a washer on the mainshaft that the earlier 86-87 motors don't seem to have.
Kinda stumped on this one. Is there another shim you speak of?
As soon as I tighten the last few bolts in the case around the countershaft it seems to lock in place.
It's literally the difference of 2-3 turns on the bolts and having the shaft rotating freely and being locked in place.

83-2004 use many similar gears.. but the shafts are diferent, because of the changed clutch-hub´s and so on. 83-87 tranny uses washers between snaprings and gears... 88 and newer has only snaprings that hold the gears on the shaft...

you could try to loose this added washer that you spoke off and sea what will happen.  at least you can only try to get a 88 countershaft or a good complete tranny ... 

[yeomans]

I think everything is in place, Been looking through the manual and online. The 88 models on have a washer on the mainshaft that the earlier 86-87 motors don't seem to have.
Kinda stumped on this one. Is there another shim you speak of?
As soon as I tighten the last few bolts in the case around the countershaft it seems to lock in place.
It's literally the difference of 2-3 turns on the bolts and having the shaft rotating freely and being locked in place.

83-2004 use many similar gears.. but the shafts are diferent, because of the changed clutch-hub´s and so on. 83-87 tranny uses washers between snaprings and gears... 88 and newer has only snaprings that hold the gears on the shaft...

you could try to loose this added washer that you spoke off and sea what will happen.  at least you can only try to get a 88 countershaft or a good complete tranny ... 
[/quote]

The added washer appears to be only on the 88 transmission.
Have given lapping some thought but that is only going to make the cases tighter.
I might have to pop the bearing out on the countershaft and try a new one all together.
Between welding and bearings, thats the only thing to have changed.
The crank is the original but was just sent out to be balanced and had a new rod and bearing installed.