philhill Posted June 12, 2009 Posted June 12, 2009 Hi, was just reading the other thread on 'new rings for DT175' and read that the clearance between the piston skirt and bore should be 0.035 - 0.04mm. I have just bought a rebored barrel, new piston, rings etc to convert my DT125MX and decided to check mine out. The bore 'appears' to be ok according to the new rings which when placed in the bore give the correct end gap but the new piston appears to rattle a little in the bore and I am able to get a 0.06mm feeler in between skirt and bore. The piston is made by MITAKA and i was wondering about the accuracy of manufacture and if this is a quality manufacturer or not ? ! Or is it more likely that the bore is not accurate. Thanks Phil
Moderator Airhead Posted June 12, 2009 Moderator Posted June 12, 2009 Hi, was just reading the other thread on 'new rings for DT175' and read that the clearance between the piston skirt and bore should be 0.035 - 0.04mm. I have just bought a rebored barrel, new piston, rings etc to convert my DT125MX and decided to check mine out. The bore 'appears' to be ok according to the new rings which when placed in the bore give the correct end gap but the new piston appears to rattle a little in the bore and I am able to get a 0.06mm feeler in between skirt and bore. The piston is made by MITAKA and i was wondering about the accuracy of manufacture and if this is a quality manufacturer or not ? ! Or is it more likely that the bore is not accurate. Thanks Phil Hi Phil, It does sound like the piston is a bit small then, however they are in fact tapered so you must measure at the bottom (skirt), I know you say you did but... The only other way is to get a micrometer and a bore gauge to check one against the other.
Moderator Cynic Posted June 13, 2009 Moderator Posted June 13, 2009 Hi, was just reading the other thread on 'new rings for DT175' and read that the clearance between the piston skirt and bore should be 0.035 - 0.04mm. I have just bought a rebored barrel, new piston, rings etc to convert my DT125MX and decided to check mine out. The bore 'appears' to be ok according to the new rings which when placed in the bore give the correct end gap but the new piston appears to rattle a little in the bore and I am able to get a 0.06mm feeler in between skirt and bore. The piston is made by MITAKA and i was wondering about the accuracy of manufacture and if this is a quality manufacturer or not ? ! Or is it more likely that the bore is not accurate. Thanks Phil I take it that the .06 feeler gague is a 'light sliding fit'. Or is it just fitiing in the gap. Aftermarket stuff generally isnt as good as the new genuine stuff, like those coils OG, but i don't think 2hundreths of a millimeter will matter on these old girls. Unless of course you want to go racing, but then you would get the pukka kit. Worst case it will be buggerd in 20thou instead of 25. The rings are the really critical part (insofar as any piston part is less than critical) and you said they are good.
Recommended Posts