top end



  • finaly got round to changing top end to day as had that ticking noise after a few minutes of running this is what i found 0_1489955914343_IMG_2314.JPG
    0_1489955943006_IMG_2315.JPG
    0_1489955975616_IMG_2317.JPG
    0_1489956019322_IMG_2319.JPG
    there is no scoring in the bore can still see honing marks but the piston has play in the bore but hard to tell from pic there is carbon on the bottom of the piston skirt so looks like it been blowing past the rings the only problem i had was the new top end bearing was very sloopy in the con rod so used the old one as was better fit not tight but no where near sloppy if that makes sense im not sure if they suposed to be like that hopfully someone will say



  • Jeez those transfers do NOT look good.

    They should not be coated in oil like that.

    Looks like an underlying problem.



  • what you thinking the problem is must admit did not see that till you said it does not smoke or use any oil



  • To my mind, not that I have any experience, that looks like clutch crank seal. Which means splitting the cases.

    See the oil is black, but the two stroke oil shouldn't have burnt at the point of the transfers.

    I really don't know but at a guess I would say crankshaft seals.



  • @Calum Ok ty mate will have to think about bottom end rebuild at some stage too should the little end bearing be loose fit as the new one supplied saw really sloppy in the rod and the old one still had play but no where near as much


  • Global Moderator

    @britshgigolo With the piston fitted to the end of the rod, it should not have any up and down play, just like the big end bearing.



  • If the little end had play, then it may have damaged the gudgeon pin. So you will want to replace that as well.

    There is some light scuffs on the barrel, nothing serious but a perfectionist would want to see that honed out.

    It may be that the barrel has worn our of shape, so even new rings won't stop the rattling.

    The head also looks like a 3BN, well worth seeing to that at this stage.



  • I have put on new barrel and 3bn modified head by Mick abbey with new piston and rings so this is going to be sent off to put on shelf once done for next time funny as have all the paperwork with bike to say had full rebuild with parts list/bill but looks like the piston was to small for the bore as got play in it it started the ticking noise about month or two after I got it



  • @britshgigolo It could just be well worn it's service limit.

    I'd take it to an engineering firm to have it examined, make sure it's within tolerance.