Steel G'Box debris identification 2017 EVO

[bikerpet]

I dropped the oil out of my EVO 300 today and found this hanging on the magnet.

It's about 0.2mm thick and 1.4mm wide. The inside edge is fairly sharp as if it's worn through perhaps, and there's a sharp edged crease on one side near the narrower end that looks like it might have been from going through a gear. 

I looked through the parts list for the gearbox, kick start and shift mechanism but couldn't see anything that looked obvious for it, there's a spacer washer on the main shaft 20x30x0.5 which is a possibility but this is much wider, thicker and a larger dia than the piece I have, there's a shim 15x25x0.8 in the clutch release mechanism, again seems a bit bigger than this fragment suggests.

Kind of wondered if it might be off a bearing cage perhaps? Or maybe the steel reinforcing from a bearing seal? I haven't had a Beta box apart before so not familiar with them.

I probed around with a magnet inside the drain hole but didn't recover anything more, also pulled the clutch cover but found nothing.

Any suggestions welcomed before I start pulling everything apart, not too excited about maybe having to split the case!

EDIT:

I just went back and had another pole around with the magnet, went higher up in the box and pulled out another bigger piece:

That's starting to look like one of the splined washers. 

Looks like it might be time to go buying a flywheel puller and work out if I need any of the "special tools" mentioned in the engine service manual.

Around 170-180 hours on the bike, new oil every 10-15 hours, nowhere near "expert" level rider so not giving it too hard a time. Was hoping for much more than that before getting to this level of repair!

 

Edited August 27, 2020 by bikerpet

[dan williams]

I agree there doesn't seem to be anything other than the splined washer that looks remotely like this. Two questions being, Why did it fail and what effect will it have on the gearbox. The only thing I can think of was one of the snap rings on the shaft was not properly placed or broke. I'm afraid you're in for a case split. Have you noticed any weirdness in shifting or unusual noises?

 

[misscrabstick]

I split a Techno engine a while back, it's not so different to the Evo, all I used was the flywheel puller and a chinese bearing puller kit to swop out the mains for new.

[bikerpet]

Thanks Dan & misscrabstick.

The question of why it failed is what I'm wondering too, definitely has me a bit concerned there'll be more damage when I get in there. No doubt all will be revealed once I get in there.

As far as shifting or noise - no difference I've noticed, and I ride it most days so expect I'd have been reasonably alert to changes. I'll take that as a positive sign!

I'll post my findings. Sadly it looks like Beta Australia doesn't have stock of the washers - things seem to have taken a turn for the worse since Beta changed importers a couple of years ago. Might be a longer wait while I get some in from the UK.

[technowaldo]

I’d be tempted just to ride it if it’s still feeling ok and let it develop you might split the crank cases and not find anything 

[bikerpet]

3 hours ago, technowaldo said:

I’d be tempted just to ride it if it’s still feeling ok and let it develop you might split the crank cases and not find anything 

I'm already into the depths. Bits of steel floating around in the gearbox aren't a long term option for reliability! Not really interested in it potentially "developing" into a major & expensive rebuild.

De-coked the head and piston, checked rings & water pump parts, waiting on a flywheel puller. Sheared off the titanium rear engine mount bolt undoing it - $50 to save a few grams! won't make much difference to my abilities.

I'll take it as a good check up opportunity.

[reggie]

I think this part could be    p/n    007041100 000                   this part was changed in the EVO era of this engine         I think I have seen one of these before that had been compromised.

[portman]

Take a look at this since that story was rather similar, bikerpet.

Edited September 3, 2020 by portman

[bikerpet]

2 hours ago, portman said:

Take a look at this since that story was rather similar, bikerpet.

Thanks. Now you've pointed me to it, I remember seeing that thread when it started.

I'm sure that's the same part. Once I've got mine fixed I might try to find out which particular washer was involved in that case and see if it's the same one.

Still waiting impatiently for a flywheel puller, and washers from the UK.

[bikerpet]

I split the case just now. It was part 35 in the parts diagram, 27.73870.000 Splined Washer.

No sign of any wear at all on the adjacent gear (Gear 4VS). The circlip however had considerable wear on the outer edge, presumably the edge facing the washer & gear but I can't say for sure (dropped it as it came off).

Washer 32 (same part no.) also shows sign of some wear - I'll replace it too.

Sadly I ordered two 73860, but only one 78370 - so wait another week or two for that to arrive from the UK. 

[bikerpet]

I was hoping to close this off with happy tales, but I'm not so sure about that.

I replaced the worn washer and retaining ring, and also the second washer on the output shaft although it was only very slightly worn. Rings, cylinder, bearings etc all checked out nicely so back together it went.

First ride I was a bit surprised by how easily the gears changed - better than new. So light and smooth changing that I was a little concerned it might jump out of gear. After a few hours it gradually went back to "like new" - a bit notchy.

After 9 hours I dropped the oil (semi synthetic 10-50 which I've used happily all along) and found it dark and ugly, with quite a bit of fine debris on the magnet. Dirtier than I've ever seen it even after my longest 15 hour interval.  ?

Changed out the oil with ATF and rode an hour today then dropped that out to give it a flush - the ATF was looking fairly ordinary already, more like what I'd expect after 5-10 hours and there was fine debris on the magnet again. Could just be left overs from the previous oil, I'll ride again tomorrow and give it another change to see.

So I'm a bit concerned that there is something going on in there that's wearing the new shim or something. I looked and looked and couldn't see anything else amiss in there, all the parts that should have been there were and nothing other than the shim washer and retaining ring appeared worn. The shift forks all indicated as straight and even as I could measure.

Why the washer & ring wore so badly is a complete mystery to me!

If anyone has any ideas what might be going on I'd appreciate hearing them. I'm not too excited about the prospect of pulling it down again, but if things don't clean up after the next oil change I'm not sure there'll be any other option.

[Jhb57]

Hi, Sorry i did not respond when you commented on my post previously, i do not come on here often. I had similar findings to you, my oil was very dirty with swarf for a few changes after i built it up. I just kept riding it and changing it and eventually it went back to normal. My guess is its the gears meshing back together as they have been disturbed. 

I had the bike for a good while after the issue with no other problems! Gear box never felt any different from when the washer was broken nor when i fixed it, not sure what caused it!

Best of luck hope yours sorts itself out as mine did.

[bikerpet]

1 hour ago, Jhb57 said:

Hi, Sorry i did not respond when you commented on my post previously, i do not come on here often. I had similar findings to you, my oil was very dirty with swarf for a few changes after i built it up. I just kept riding it and changing it and eventually it went back to normal. My guess is its the gears meshing back together as they have been disturbed. 

I had the bike for a good while after the issue with no other problems! Gear box never felt any different from when the washer was broken nor when i fixed it, not sure what caused it!

Best of luck hope yours sorts itself out as mine did.

Thanks, that's somewhat reassuring.

I'll give it a few more (frequent) oil changes and hope for the best.

I hate it when something breaks for no apparent reason!