Sprag clutch fix gone bad - crankshaft moves? Please help!

[RokRoland]

Hello all,

posting here for the first time (and in somewhat sad circumstances). I've owned a '03 RSV for a bit over 2 years now, it's done a bit over 40k kilometers and a week ago the sprag clutch finally caved in. Fortunately, I found lots of useful info here on how to go about fixing the thing. Long story short, had trouble acquiring the special tools and had to settle for generic ones. Afterwards, had trouble finding TDC (apparently) and using the (110mm bolt) crankshaft locking tool. Opted to use a wrench instead, which worked but unfortunately fouled my flywheel a bit. Tried to head up the flywheel with a tiny propane pistol-shaped thing, ended up with a useless flywheel removal tool. Got a new tool (this time proper grade steel) and borrowed oxy-acetylene gear, thing plopped out beautifully.

Cut the spring on the sprag, it's beautiful now. Reassemble.

But.

Upon tightening the flywheel bolt to spec (128 Nm, 94 lb-ft I believe) applying proper loctite as well. Then, I notice the flywheel and the axle are moving. They're moving a lot, at least 10mm. I can pull outwards on the flywheel and there is definitely a lot of play, a whole lot of play indeed. I am not entirely certain as to what is happening, but as I assume the flywheel bolt goes to the end of the crankshaft, the entire crank must be moving. At this point I decided to stop doing anything before I figure out what is going on, and definitely not completing assembly and firing it up.

So, my question is, what has gone wrong? I don't seem to be having any extra parts left over (though any ideas are welcome at this point). Can there be an error in assembly? Did I manage to do damage to the crank while pulling out the flywheel unsuccessfully? Could my crank locking tool-misadventure have caused damage? The use of the crank locking tool was definitely scary - I figured I had got it in the right spot but then apparently I didn't as the engine turned eventually.

I am posting a very poor quality Youtube video of a very tired me pulling out on the flywheel, plus rotating the engine from the flywheel. If anyone has any clue as to what is going on, it is much appreciated.

I guess hacks like me should stay away from anything more challenging than changing the brake pads.

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[RokRoland]

Ok, replying to myself...

I had a few cigarettes and went back to the shed to take a look at the bike again, and noticed that there was no play at all. This made me scratch my head quite heavily.

It would appear that the play is only evident once the engine is cranked the wrong way. As I was tightening the flywheel bolt, this occurred due to my wrench slipping. When cranked the right way, there is zero play on the flywheel. Now, I am considering that this might not be an issue at all as the engine only rotates in one direction during normal operation.

There was quite some play in the sprag gear behind the flywheel though, at least 2mm, but it was still making good contact with the neighbouring gear at any position, and the position of the sprag gear did not seem to cause any variation in the operation of the gears.

Now I am thinking I might be home free. Any insight into the matter is still of course highly welcome.

[deefred]

Could you have overtightened the crankshaft locking tool?
Only a few Nm are allowed as you put a direct lateral force on the crankshaft

[RokRoland]

Thanks for your reply, Deefred. Today, one day wiser, I can probably answer my own question.

Talked to a local racer / engine builder today. He stated that in most engines such crankshaft play is normal, and there is no need to worry. Encouraged by this, I put all the bits together, and off she started like never before. 300km trip later, everything seems normal, except the bike is charging well (brown connector etc. mods done at the same time) and the starter is beautiful - sorry I have to say this but like in my buddy's Honda. Totally no-nonsense, all business, starts right off the bat. I am hoping this behaviour continues from now on.

On the crankshaft locking tool, the bolt I used was only threaded about 1/3 of the way, so I presume the bolt did not make it far enough - I calculated that a 100mm fully threaded bolt would have been about 20mm deeper in the engine. I did not use heavy torque when inserting the bolt, just finger tight using the Allen key that had maybe 15cm of leverage.

If someone wants to stand up and tell me to stop using the bike now and dismantle the engine to prevent future damage, I am listening.

[vonDutch]

What you feel is indeed the axial play of the crank shaft. At first I thought you showed radial play. That would of been bad lol.

With all bad luck in the world, there is no way that you would be able to fek up the axial play by removing the flywheel. You press off the flywheel by pressing against the shaft, and thats it... The way you described how you removed the flywheel is the same way I've been doing for many times now (and I am using a Scania m22x1.5mm wheel bolt as special tool).

The sprag gear move between the inside of the flywheel, and an aluminum lump on the left hand side casing. Again, there is nothing that you could have done wrong to increase that play.

I'd say job well done. Nothing to worry about. Your engine is fine.