TheBoltons Posted August 3, 2012 Posted August 3, 2012 Hi all... just discovered a small leak at the bottom of the crankcase, so while replacing gaskets etc, checking everything else on the way through, and would like your opinions on the state of the piston - here she is: I haven't cleaned it up or anything, and there is a SMALL amount of carbon deposit there... opinions? Thanks all.
Moderator Airhead Posted August 3, 2012 Moderator Posted August 3, 2012 looks ok to me but the best bet is to hone the barrel and fit new rings
TheBoltons Posted August 3, 2012 Author Posted August 3, 2012 okidoke - thought as much, but wanted a more learned opinion - thank you for providing that!
Moderator DirtyDT Posted August 4, 2012 Moderator Posted August 4, 2012 Cheap to do and the piston is out. That sound like new rings time to me.
TheBoltons Posted August 4, 2012 Author Posted August 4, 2012 Rings are immaculate... Checked everything with the manual and everything is new spec also been informed that rings were replaced fairly recently. Am replacing all the gaskets, even though theyre all in good nick.
Moderator Cynic Posted August 4, 2012 Moderator Posted August 4, 2012 Don't care with the piston on the bench, change them. There is just too much work on a diesel to not swap out the rings.
mike1949 Posted August 4, 2012 Posted August 4, 2012 Take Cynics advice, after all he's a member of the piston broke club.
blackhat250 Posted August 4, 2012 Posted August 4, 2012 By diesel" he means 4stroke,,,, ,, complicated boring fkers of things,,
TheBoltons Posted August 4, 2012 Author Posted August 4, 2012 Ok, ok, will fit new rings lol Also, just an observation, but the cam sprocket was the wrong way round... Just to make things awkward... Meant I couldnt check positioning very easy on removal. Guessing it was done when the rings were installed. Found a few more little gems too, like the oil filter which was the wrong type so it just got hammered on... And after all this, I may need to replace the central crankcase gasket! Grr. My bro in law has a lot to answer for. Or the idiot that he bought it from... Sigh... New parts all ordered, so once ive dealt with them its just a case of putting it all together then a proper road test, which I haven't been abke to do since I got it :-)
Naughty Nigel Posted August 13, 2012 Posted August 13, 2012 It's well worth while having the cylinder honed. This breaks any glaze and the hone marks hold oil, which will help to bed in the new piston and/or rings. However, check the bore for ovality, and for a wear ridge at the top of the bore. If there is a wear ridge it might break new rings unless ridge-dodger rings are fitted. (I don't know if these are still available.) An oval bore may also allow piston slap and excessive oil consumption. In either case a rebore might be the best option. You can also break any glaze in the bore with 400 grit wet or dry paper and a bit of oil. Try to rub at 45 degrees rather than up and down the bore. Just make sure you wash it out thoroughly afterwards. NN
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