Honda XL185 Rebuilt Crankcase, Mainshaft binding?

Hey guys, I've recently rebuilt the gearcase on my XL185. I replaced all the bearings in the box, and thoroughly cleaned everything.

I am certain that everything is in, in the correct positions, and the forks etc are all working.

As I have reassembled it, the mainshaft and counter shaft both spin smoothly. Once reassembled without bolts, it's all fine. Once I have tightened the gearcase bolts (that hold the two halves together) the mainshaft is much harder to turn (basically you can't turn it without some sort of leverage), you can't turn it just by hand...

What would cause this and how can I fix it?

All I can think is, either a bearing is sitting too high in the case, causing the two cases to essentially 'squash' one of the shafts, making it all bind up, or a thrust washer is in the wrong place or is too thick basically...

Frustrating problem frown.gif

As it is, I can turn the shaft with the kickstarter by hand, so I am assuming the bike would run, however I'd imagine one of the shafts would be thrusting hard against a bearing until it wears in...

Did you put a gasket between the cases like the Honda factory does or just us some sealant like yamaha and others do ? 

Hi BruceD, I used a gasket rather than sealant. I have had someone suggest the old thrust washers could be the issue? However I would not have assumed old thrust washers could cause this, as they would be worn resulting in looser tolerance rather than tighter...?

I can't see the thrust washers being making a problem either  :huh:


Check second and first (opposite ends of the counter shaft) and check 5th gear on the end of the main shaft.


There is one of those gears that goes on quite nicely upside down and causes what you're talking of.  I've done this my self on the XL125's (identical transmission almost) and had this situation. I just forget which one of them it is. It'll be obvious when you flip it around it will sit down a little lower.

Edited by BruceD_500

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