KX Riders
Maintenance & Technical => KX250 / KX125 => Topic started by: staffylad on March 22, 2014, 02:43:19 AM
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never trust someone to do the work on your bike :|
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huh...do tell.
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should ther be any play on the pison from side to side and the arm moves side to sided but up n downs ok :)
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hopefully you're experiencing this while the cylinder is off?? :?....
there will be "some" side to side play...unfortunately I don't have the extra parts lying around to take pics to show you, but there has to be a little play, otherwise the rod would be tight against the piston...and it wouldn't be able to rotate as it went up and down...do you follow? :wink:
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seems a lot to me and the piston was moving side to side a lot aswell,its been scrapin up the side on the bore at the bottom,im in 2 minds weather to do this top end incase the conrods not right ,could ther possibly be the wrong size bearings in causing them to have toomuch play to cause the piston to do that to the bore ..:)
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when your motor was rebuilt, what was claimed to be replaced?...it is possible the big and small end bearings were'nt replaced, and the ones in there now are shot....
if your cylinder is getting scored up, I wouldn't run it any more until you find the root cause of the problem....post some pics and even video so we can see what's going on, and hopefully be able to better help you.
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the cylinder heads off now on the bench,the crank is submerged in water,the bottom of the bore is scraped and so is the piston down onside,the scrap on the bore is at the bottom of the front ,he claimed to to have replaced the crank and conrod but it looks like my old crank with a new conrod wich is movin side to side and the piston was moving side to side a lot,they both seem to have a lot of play sideways,the top bearings look new and the rings are but the piston looks like my old one,it was running when I got it back,ive rode it once took it out wouldn't start took the plug off and it was sprayin water up,so I took the head off and I think it hasn't been skimmed but the play on the conrod has to be the reason for the piston scraping the bore? that's my thoughts so far lol ... :|
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(http://i1067.photobucket.com/albums/u424/staffy32/DSCF0719_zpsdc4ed20c.jpg) (http://s1067.photobucket.com/user/staffy32/media/DSCF0719_zpsdc4ed20c.jpg.html)
(http://i1067.photobucket.com/albums/u424/staffy32/DSCF0720_zps7250c041.jpg) (http://s1067.photobucket.com/user/staffy32/media/DSCF0720_zps7250c041.jpg.html)
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hmmm :|...try to get a few more pics of the cylinder plating, on the exhaust side too...it looks questionable in that one pic.
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(http://i1067.photobucket.com/albums/u424/staffy32/DSCF0723_zps2ce316b8.jpg) (http://s1067.photobucket.com/user/staffy32/media/DSCF0723_zps2ce316b8.jpg.html)
(http://i1067.photobucket.com/albums/u424/staffy32/DSCF0721_zpsae10760f.jpg) (http://s1067.photobucket.com/user/staffy32/media/DSCF0721_zpsae10760f.jpg.html)
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The plating looks like it is worn out around the exhaust port, although it's hard to tell.
Get a feeler gauge and measure the crank to rod side clearance and tell us what it is.
I'm guessing that the cylinder was not plated or even honed before the new piston was installed, is that correct?
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yes its looking like the head hasn't been skimmed causing this problem so its a new top end build :)
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someone says don't skim the head do it yaself with a grindin plate becos they take toomuch off apparently and the bores looking like its nickel so I might just get away with rubbing it down and putting a new piston in + gaskets but I think I will get it skimmed as these are wer the problems started :-D
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Motorrad turned a bunch of us on to Time Saver lapping compound....works awesome. You'll need a FLAT surface to work on...I snagged a nice piece of 5/8" safety glass from work and had it cut down to 20"x 20", it's a little big and heavy, but works perfect for lapping cylinders and heads...but any hard flat surface will work. You will want to pull the cylinder studs and lap the cylinder along with the head, so that BOTH mating surfaces are flat...no point in doing one and not the other.
(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/ts_zpsec9453d6.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/ts_zpsec9453d6.jpg.html)
you can get it here, or other places that might be more practical shipping cost wise....you want the Yellow Label 100N as shown here...
http://www.ws2coating.com/timesaverlappingcompounds.aspx
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cheers beaver ive just been polishin me head I like to take the clear coat off and shine them up :-D
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I likes a good head polishin me self. :-D
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bores looking like its nickel so I might just get away with rubbing it down and putting a new piston in
I would find out what your current piston to cylinder wall clearance is, and have the inside of the cylinder measured, before just "rubbing it down and putting in a new piston". The pics of your cylinders plating are questionable whether it needs to be re-plated or not.
I'm not sure what the maximum/minimum service limit wear is on the 94, but you should be able to call your Kawie dealer for that, or you might find that info on here.
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thanks beaver always helpful m8 i love this site,im gonna take the bore to armstrongs tomorrow get it inspected id rather have it doner right before I waste more money on parts,rather do a tiptop job quality time took is where the passion is lol :wink:
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im gonna take the bore to armstrongs tomorrow get it inspected id rather have it doner right before I waste more money on parts
there ya go!!....let us know how things go and what you find out.
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barrels nickel plated so its getting honed and top end kits on order jst putting a mitaka in good enuff if you look after it,i think wit throttle stickin on etc its just rove the arse off it but that should be ok now ive replaced the carb kit ,ive rebuilt the whole bike nearly lol im gonna order a new coil aswell I don't think its been replaced since 94 :roll:
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new carb kit in,took ages to find the parts,from Netherlands ,found out needles from a gas gas 250.. :roll: