Kinda fed up posting things like this now, seems the bike dosent like summers, now winter is heading our way its back in the garage all repaired but off course its raining and the forcast looks shite. Anyway Pics of the damaged piston and bearing are now here for anyone that wants to see a snapped lug from a crank bearing make its way round to the oil feed hole, jump in to the crank and get sucked up into the chamber, distroy another piston and give me another bill, GREAT!!!!!

1. Piston and Lug imprints
http://www.bikepics.com/pictures/663191/

2. Whats left of the Sheard Lug on the bearing
http://www.bikepics.com/pictures/663193/

3. Shape matches nicly
http://www.bikepics.com/pictures/663194/

4.some damage (look closely on the race) on the bearing
http://www.bikepics.com/pictures/663197/

5.ring damage left, broken lug damage right
http://www.bikepics.com/pictures/663198/

Have to bear in mind here that the Crank (bearings come with the crank right?) is 3000kms old, and was fitted profesionally so why has this happened? cant understand it myself which is the most anoying? anyway have a look, at least it may help soemone later or add to the tech'y knowledge base!!!

Very interesting. Thanks for sharing that with us. It looks like that bearing was getting very hot. This may be a case of which came first: the chicken or the egg? If I had to guess I would say the ring broke and washed itself through the motor; got into the bearing and caused the bearing to stall.
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james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm

I would have to agree with James on this one. The two main reasons why this would have happened is either the RC valve was improperly adjusted (snagging the ring) or the ring end gap was too tight.
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Mike

If the lug was inserted in the oil hole in the crankcase, this could lead to the bearing failing, because of lack of lubrication.
As the oilhole probably isn't a tight fit, for the lug, it will eventually break, because the bearing now has high friction and the shell will move and hammer the lug into on side of the hole and shear it.

Being inserted in the oilhole, makes it easy for the lug to move into the crancase and be sucked(or shot up as there isn't much room in the case) up on top of the piston.
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Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom

Black Magic i say worth pointing out the bottom pic is comparing the piston from the original failure with the one after the repair whic then failed. not the same siezure.

intrestingly, there is loads of play in the bearing, side to side and up n down, and it makes a rough noise when spun, as for the oter case spinning, once the case's are together it should be an interferance fit making it very hard to have the outcase spin. also i mentioned in a previous post that there was a grove in the case from the lug moving!!!!!!!

On the bright side, i got to run it up last night and fill the garage full of smoke........Inhail for a few mins, big sigh the switch off body work back on today, and BIG thrash planned for the weekend, rack up some miles to make sure all is well......

Hopefully that's your share of bad luck over with for a couple of years now!

We all go through a bad phase at some point. I guess I was lucky and managed 10 years... then I met StephenRC45 and his quest for the last hp!!
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Andy.
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Oh yeah, you took a lot of convincing.. can we just, and then, and maybe fit this lol
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If I have to take the carbs off once more...

_________________
Andy.
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BAD luck, feck bank manager is twating me over the head, LOL always in hindsite, but i didnt buy stephens engine cause it would have cost around a £1000 to buy and get set up, so now i have a bill for £700 for the first repair and now £300 for the second LOL thatll teach me, i could have had spare parts for sale and a 300 DOH!!!!! oh well!

New forks and shock on this weekend and ill be ready for that bloody posser board, Do i get extra for most amount of money spent on rebuilds in such a short time? LOL

We know someone who can laugh in the face of your £1000 expense... don't we Fontyyy!

Stephens old 300 was flying at Llandow too, even on very conservative jetting!!

Still, live and learn eh?! Enjoy the weekend!!
_________________
Andy.
NSR-WORLD.COM

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Andy wrote:We know someone who can laugh in the face of your £1000 expense...don't we Fontyyy!

errrrrrrrrrr ive also got a black hole for a bank account with doing the 21

Andy wrote:We know someone who can laugh in the face of your £1000 expense... don't we Fontyyy!

Stephens old 300 was flying at Llandow too, even on very conservative jetting!!

Still, live and learn eh?! Enjoy the weekend!!

I must admit, it was Andy`s "Christ on a bike" speech that made me buy the kit from Steve. (Now you know who to thank Stephen). Before that I wasn`t that interested in the 300 kit. The bit about the new Honda barrels swayed it. I was just going to get my siezed 250 barrel replated before all this.
Still, now I`ve got some spares to use on the race bike.
Now yours is sorted you can go out & enjoy it, won`t matter what cc it is as long as you can ride it, who cares?