gronno Posted January 9, 2010 Report Share Posted January 9, 2010 New poster, from wintry south west Wales. We've just finished a full rebuild of my lads TY80 which took Dad rather a long time to complete (ahem). Anyway, it ran really well which was a relief, right up to the point where he toppled over on it and it ran for a few seconds on it left hand side. It didn't over rev just lay on it side at idle. While it was over and as I sorted the boy out, I heard what sounded like the chain trying to jump of the sprocket so quickly hit the kill button. The bike stopped as I hit the button but was now locked solid when in gear. I thought something had come adrift in the gearbox but now I've stripped it down, the problem is obvious. A small ring or washer looks like its found it's way into the crank case and jammed up the piston skirt followed swiftly by bits of skirt jammed against the flywheel and cases. Crank is out and all bearings seem OK, new piston and it should be fine, fingers crossed. I just can't figure out where the steel washer/ring thing has come from. I attach a pic for the more experienced engine fiddlers to hopefully identify the part! http://i192.photobucket.com/albums/z6/gron...20Pics/FOD1.jpg Thanks for any help guys, Gronno Quote Link to comment Share on other sites More sharing options...
richty250e Posted January 9, 2010 Report Share Posted January 9, 2010 Hi Gronno, Just looks like a spring washer that has been sitting in the crankcase or some part of the air inlet duct after the rebuild and was dislodged and then sucked into the cylinder when the bike fell on its side. its easy for a stray washer to fall into the crankcase unnoticed. Always good practise to put clean cloths around the crankcase mouth when working on the bike to stop things falling in. Not pointing any fingers but young kids also have a habit of picking stuff up and pretending to mend the bike 'like dad' and then dropping things into inaccessible places. Keep an eye on them if they're in the garage! Had a similar thing recently when someone changed a liitle end bearing and a needle fell into the crankcase unnoticed, it was later sucked up into the transfer port and jammed the piston. Unlucky really after all the hard work you've done. Rich Quote Link to comment Share on other sites More sharing options...
big john Posted January 9, 2010 Report Share Posted January 9, 2010 I would tend to agree, its either fallen into the crankcase during the rebuild or it has been in through the airbox, only two believable entry routes, its via the induction tract one way or another! I had a short length of copper wire stop a Bultaco motor recently and fortunately didn't do any damage, parts of it were fornd on top of the piston in fact. Again a previous rebuild with the said "foreign body" entering the motor when not protected by a rag or blanking piece was the most likely culprit! And before anyone says something, I hadn't rebuilt this particular motor myself. I do tend to "blank off" with duct tape, the inlet tract even when I'm working on a carburettor!!! Big John Quote Link to comment Share on other sites More sharing options...
gronno Posted January 9, 2010 Author Report Share Posted January 9, 2010 Ta for the replies boys, yes I was little upset it was running so sweetly too. Funny thing is it's not a spring washer for definate, there a diamond pattern stamped into either side looks more like a location ring of some sort. Anyway it's back together now, ordering a piston tonight . Quote Link to comment Share on other sites More sharing options...
feetupfun Posted January 9, 2010 Report Share Posted January 9, 2010 The diamond pattern looks like the pattern that would be made if the washer was gripped in the jaws of a bench vise Quote Link to comment Share on other sites More sharing options...
axulsuv Posted January 9, 2010 Report Share Posted January 9, 2010 (edited) I to agree with the gents above , I would wager it's not a Yamaha part ... Looks to me to be a high grade high collar lock washer , I've seen some before with the stamping on the sides and not sure where I remember it from ... Maybe electric motors or something with high frequency vibrations . Or maybe from a old british leyland product ....(jags , real ones , pre 1980...) Or it could be the alignment washer out of your astro-diffibulator commutater brush alignment assembly ! Glenn Edited January 9, 2010 by axulsuv Quote Link to comment Share on other sites More sharing options...
b40rt Posted January 10, 2010 Report Share Posted January 10, 2010 I to agree with the gents above , I would wager it's not a Yamaha part ... Looks to me to be a high grade high collar lock washer , I've seen some before with the stamping on the sides and not sure where I remember it from ... Maybe electric motors or something with high frequency vibrations . Or maybe from a old british leyland product ....(jags , real ones , pre 1980...) Or it could be the alignment washer out of your astro-diffibulator commutater brush alignment assembly !Glenn Your saying Aliens "f**k*d" his motor ? Quote Link to comment Share on other sites More sharing options...
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