Mp3 yourban transmission problem
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Member
Piaggio yourban 300
Joined: 17 Jul 2019
Posts: 16
Location: Amsterdam
Tue Dec 17, 2019 12:27 pm quote
This happened to me recently. I was driving slowly until suddenly a very loud sound came out of my vario. I stopped to look and I couldn't push the mp3 anymore, the rear wheel was stuck. When releasing I only came across horror.

All gears have damage, and the other is completely broken. I can be happy that everything has remained stuck.

Everything ordered new. I want to take the bearings out and the first one went out easily. Then I started on the 2nd and hit a hole through the other side.

For when you wonder how I did that and how you should never do that. I use wet paper. With this I completely fill the bearing and insert exactly a piece of metal in it. With this you can easily remove the bearing. I did not realize that the back is very weak and I could break it like that.

Now I have special glue that I hope will stick to it. It was exactly 2 pieces broken in half.

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Ossessionato
Gilera Fuoco 500ie
Joined: 11 Oct 2009
Posts: 4207
Location: Netherlands Olst
Tue Dec 17, 2019 1:45 pm quote
the best option is to weld it
Hooked
Piaggio MP3 500
Joined: 21 Nov 2017
Posts: 288
Location: Austin, TX
Tue Dec 17, 2019 2:31 pm quote
I'm glad you're OK- that sounds like a very scary incident.

Really, the best option is to buy a new case half. Welding would require machining, which would require you to remove the engine anyway, and it would still be weaker than the original engine case casting.

If it were me with this problem, I would either buy new castings, or look for a scrap engine. I would worry that the glue would come apart while I was driving, and cause an accident.
Member
Piaggio yourban 300
Joined: 17 Jul 2019
Posts: 16
Location: Amsterdam
Wed Dec 18, 2019 2:01 am quote
welding is an option, but this is so small that the chance of burning is high. if the glue does come off, only oil can leak. the bearing is still behind its edge. It doesn't hold much. I'll see if the glue holds it. if it is not, then I will see if I can weld it.
Hooked
2009 MP3 400, 2004 Honda ST1300
Joined: 11 Jun 2007
Posts: 254
Location: Sayre, PA
Wed Dec 18, 2019 3:49 am quote
If that's a blind hole, (the piece that broke out completely fills the bottom of the hole), then I think this should would. The bearing load will still be solidly supported in the main part of the case. The epoxy and the broken part are just filling the hole to keep the oil in.

I would be concerned to find the root cause. This seems like a rare failure.

This does give a person concern about using the wet paper technique to extract a bearing.
Hooked
Piaggio MP3 500
Joined: 21 Nov 2017
Posts: 288
Location: Austin, TX
Wed Dec 18, 2019 8:00 am quote
Which came first? Did the case crack which loosened the bearing which allowed the shaft to be misaligned, and with torque snapped the shaft, or did the shaft break, which caused the bearing to fracture the case? If it's the first, then the root cause is still present, which is asking for another failure. If its the second, then the glue will probably hold OK. But I still think if you do a repair, unless the parts are unavailable, you should do it right; use new parts to replace the failed parts whenever possible.
Member
Piaggio yourban 300
Joined: 17 Jul 2019
Posts: 16
Location: Amsterdam
Wed Dec 18, 2019 12:46 pm quote
I still don't get the broken rod. The bearing was not good I saw afterwards. But that is why no rod of 3 cm thick can break.

The broken piece of carter came because I hit too hard to get the bearing out. After gluing, it all seems to hold well. I'm still waiting for a bearing and turning and then everything in the transmission is new.
Hooked
Piaggio MP3 500
Joined: 21 Nov 2017
Posts: 288
Location: Austin, TX
Wed Dec 18, 2019 3:11 pm quote
My bad- the shaft looked broken in the second picture...

My guess that the cause was a bearing failure and going over a bump afterward. So the glue may work OK.
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