Gearbox primary shaft bearing replacement

[drca]

I screwed up and now I need help to fix my mistake...

It all started with a crash and loss of clutch pressure at the lever.  It took me a while to diagnose it to a pinched (and punctured) hydraulic line: the line got pinched between the frame and the lower triple clamp dring the crash.

In the process of replacing the clutch line I decided to change the hydraulic fluid and "upgrade" to DOT 5.1 (which is compatible with both the oil and brake fluid systems).  So to do that I took off the right side engine case to flush the clutch slave cylinder.  Since I had changed the oil recently on the bike, I just laid the bike on the left side and proceeded with taking off the side case, flushing the old fluid, replenishing with DOT 5.1 and put the case back on the bike.  Then I put in a new clutch line, took the master cylinder apart and cleaned everything, filled up the system with DO 5.1, bled it and off we go.  Fired up the bike to make sure it worked, no problem, good to go riding the next day.

The next day, take the bike off the truck, fired it up and... clunk clunk cluck goes the engine 

So right there in the parking lot and lay down the bike and take the clutch side case off and what I saw was the clutch need thrust bearing and washer laying at the bottom of the engine. What I think happened is that then I put the case back on, the washer and thrust bearing must have slid down the slave cylinder and fallen off in the engine main cases.  For some reason nothing happened when I fired up the bike after putting it back together, but the next morning all hell broke loose.

Here is what the thrust needle bearing looked like (not bad, just a couple of needles dropped off):

So yesterday I took the engine off the bike and carefully drained and strained the oil, opened the clutch side case, took the whole clutch assembly apart and looked for damage.

I found one of the needle stuck to the magnetic fill up plug 1/4 chewed, and a bunch of metal "dust" on the clutch assembly.  I flushed the whole engine several time with gas and didn't see anything else coming out.

I put everything back together today, filled up with oil, fired up the engine and here is what I got (video).  Not good.

It's a little better when I pull the clutch but not much.

So I took the engine case off again and it looks like I have some play in the bearing primary shaft: when I push it side to side I can definitively feel and hear some movement.  Here and here are a couple of videos.

I inspected the teeth on all the gears and there is only superficial scratches on them.

So... Looks like I'll need to split the cases and replace at least the primary shaft bearing.

Hence, here is the question:  How complicated is that?  What special tools are required if at all?  How much would a shop charge if I were to take the engine to them to do this (not including price of parts of course)?

Thanks for the help.

[peterb]

Probably not a good move to change to DOT 5.1 for the clutch as the system uses mineral oil for the hydraulic fluid, I don't believe DOT 5.1 is compatible and would swell the master cylinder seals. The slave cylinder O rings are teflon coated so would just need a clean. Best to use a dab of tacky grease on the slave piston to hold the thrust bearing and washer in place when re-assembling. There is usually a fair amount of swarf behind the clutch belleville washer (spring) so I wouldn't take it for granted that the other needle roller has been minced. Have an even closer look at the kickstart idler gear and clutch ring gear, it doesn't take much at all to damage one of the gear teeth and make a clunking noise, though if not too bad, you can use slip stones to ease back the damage. Would pay to strip the motor and look for the lost needle, then at the same time replace all of the primary and secondary shaft bearings while stripped out, they don't cost much. Definitely replace the 2 sets of 1/2 needle rollers as these wear quickly and can cause more problems. Only real special tool you'd need is a flywheel puller. Bye, Peter B.

[copemech]

sounds as though the other roller got between the primary gears and damaged them.