shercoben12 Posted June 12, 2013 Report Share Posted June 12, 2013 hi i have an 08 125 racing thats had a new piston about 20hours. the bike has plenty of power now and has enough compression. but there is a small rattle when reved on the run down. it is not the clutch rattle. it is quite annoying... if i take it round the field under load it seems to get a little quieter but then it comes back. is there any way to change this or will it go? Quote Link to comment Share on other sites More sharing options...
shyted Posted June 12, 2013 Report Share Posted June 12, 2013 (edited) Hi Ben . I know your only a young lad so will try to explain a few thing's without mixing you up . Did you replace with a full piston kit ( little end bearing ,dudgeon pin , circlips ,gaskets )? Did you measure any clearances ? They would be between the piston and cylinder , and the piston ring (rings) when in place on the piston . That will be the gap between the two ends . You would need to find out from Gas Gas what the tolerance is . You can see in any Haynes manual for two stroke bikes how to measure . Did you fit everything ? Check your work . Every one makes mistakes.It's hard to diagnose over the internet but gather information and your halfway there . Let me know how it's going and if i can help i will . Ted . Edited June 12, 2013 by shyted Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted June 12, 2013 Author Report Share Posted June 12, 2013 Hi tedd. Thanks for the reply! The piston kit was professionally fitted by freestyle bikes of wadhurst. This included all bearings/gaskets/clips. It was a full top end rebuild. I am going to try and take a video of it now so you can hear it. It should be up on here this evening. Thanks, Ben Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted June 12, 2013 Author Report Share Posted June 12, 2013 (edited) i know there is usually abit of mechanical noise. http://www.youtube.com/watch?v=xfz9gzll-BM in the video you can slightly hear it but it gets louder when the bikes hotter. the noise varies. sometimes its quieter then others. i guess if its still runs fine then there is nothing to worry about. it is slightly annoying though. if there is a way to get rid of it except from putting a new piston in it would be nice. you barely hear it in the video which is annoying:( Edited June 12, 2013 by shercoben12 Quote Link to comment Share on other sites More sharing options...
shyted Posted June 12, 2013 Report Share Posted June 12, 2013 (edited) yep can hear that and sounds like a bearing noise over the internet . Without being there could not say at this point one hundred percent .You've had work done professionally . So phone them up tomorrow get your receipt , quote your receipt number and name etc and explain the bike has developed a problem . Be polite . You want a fix not an argument , and preferably for free ,so be rational . My advice to you is put the bike in the van and take it back and see what they have to say . You have paid for a service and for parts ,if one or the other is faulty then you have rights .Just don't let them fob you off .Go about things the right way to get your result . Don't pull anything apart ' because then it's on you . The fact that the noise is there when cold and gets worse when hot says you have a problem . Tomorrow don't mean Saturday ,act now . Good luck ,and be polite remember . Keep me posted . Ted . Edited June 12, 2013 by shyted Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted June 12, 2013 Author Report Share Posted June 12, 2013 thanks ted will do exactly that. i knackered the kickstart gears a few months back and sent it to them to sort it out. they said it was the big end! so we took it back and did it our selves with new gears. so starting to think if they are really "proffesionals" Quote Link to comment Share on other sites More sharing options...
dadof2 Posted June 12, 2013 Report Share Posted June 12, 2013 Very difficult to diagnose over the internet but sounds like a mix of bearing wear and piston clearance to me. Hopefully your dealer will sort it. An easy check is to take your exhaust off, put your finger in the exhaust port and try rocking the piston. With piston just below TDC try putting a 0.0015" feeler gauge between the piston and the bore above and below exhaust port. If it slips in easily there is excess clearance between piston and bore. What oil are you using and at what mix ratio? Many synthetics only have a viscosity of only 5 to 8 cSt when hot and a very thin oil film. Try something like Castrol A747 at 30 :1 that has a viscosity in excess of 20 cSt when hot, This may quieten it. I would not run the bike much until you know what the fault is. It may be the bore has a lip at the top and the new upper ring is striking it. Cheers Quote Link to comment Share on other sites More sharing options...
copemech Posted June 13, 2013 Report Share Posted June 13, 2013 Sounds like a normal rattletrap to me! You wil not restore the cyl without a replate and that will cost you a couple! Ride it! Not that bad! Quote Link to comment Share on other sites More sharing options...
shyted Posted June 13, 2013 Report Share Posted June 13, 2013 (edited) Sounds like a normal rattletrap to me! You wil not restore the cyl without a replate and that will cost you a couple! Ride it! Not that bad! So he paid for a service and parts by people calling them self professional and as an adult your advice to a 13 year old lad is just ride it . If that was your child and there was an engine faliure which resulted in an off and stitches or a break how would you react ? The chance is small ,but nonetheless exists . Take it back and as they are actually there they get the problem solved . Not looking for an argument copemech but don't think his mother would not appreciate the likes off you and me telling him to go ahead and ride should he be hurt as a result . Ben , ask them to show you what they find . If you can stay there and ask them to strip it . Take someone with you who knows what they're on about.If they measure the clearance between the bore and piston it's measured at the crown (top) and skirt (bottom ) on the exhaust port side as your model of 125 does'nt have a tapered cylinder bore (wider at the bottom of cylinder than top ) so you should have a specification for that . GasGas uk 01298 766813 ext 4 and kev will give that to you should you need it . I take it from your post that the noise developed after the work . Regards Ted Edited June 13, 2013 by shyted Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted June 13, 2013 Author Report Share Posted June 13, 2013 ok, spoke to dealer today and they said they will have a look for us. but he said he wouldn't be surprised if its the big end. :moon: . when they said that last time it was the kickstart gears. they didnt even take the barrel of to see if there is any play. they just listend to it... i will take it to them and get them to prove its the big end! if not then they will sort it!!! Quote Link to comment Share on other sites More sharing options...
shyted Posted June 13, 2013 Report Share Posted June 13, 2013 You want everything on paper Ben and ask to stay while they strip the bike . Make sure they measure the clearances ,no second guessing , make sure they don't try and say something wrong and it's not . Mean while do some reading on how you get the measurements , as i said if you talk to ,or send Kev at GasGas an e mail , he will help you , or any of the lad's there . It's difficult because you are so young and people can take advantage of your lack of practical skills and level of understanding but let them know you're not just taking their word for it . Good luck Ben and remember stay polite . Ted. Quote Link to comment Share on other sites More sharing options...
copemech Posted June 14, 2013 Report Share Posted June 14, 2013 (edited) So he paid for a service and parts by people calling them self professional and as an adult your advice to a 13 year old lad is just ride it . If that was your child and there was an engine faliure which resulted in an off and stitches or a break how would you react ? The chance is small ,but nonetheless exists . Take it back and as they are actually there they get the problem solved . Not looking for an argument copemech but don't think his mother would not appreciate the likes off you and me telling him to go ahead and ride should he be hurt as a result . Ted, I would like to share with you a little revelation I have discovered after 45 years or so of riding dirt bikes, TWO STROKES RATTLE! And some worse than others! The fact that even by Ben's own admission that it is not that bad in the video and seems to come and go a bit does not neccessarily suggest the thing be condemned. Of course not being there does not help, so we must rely upon Ben's judjment and hopefully even a comparison with other similar bikes. From what Ben has stated, it would suggest that a simple refresh was done with new piston and rings, yet I would doubt the bore was replated unless a major problem had been noted at the time, not sure. Long story made short, it only takes .01-.02mm of bore wear for this type thing to occur, which may still be considered negligible for the most part by many. Just takes more $ to fix up! And all said, they will still loosten up and rattle before long. Of course when we were Ben's age, not only did we have to walk seven miles in the snow to get to school, but we were darned happy to have a bike that only rattled a bit! Meant they were just getting loostened up enough to be a good runner! Now I realize Ted may be a bit paranoid after mum dropped him on his head, but I am not quite there yet and will rely upon Ben's good judgment or hopefully another opinion in person by someone familiar with the bikes since we cannot be there. Not sure this shop is totally up on their trials bikes either, things would have to be much worse before I would suggest a big end problem which is seldom for the most on these things, and that stuff does not come and go to fix itself. Must be a qualified ear around somewhere? No harm, no foul Ted, just taking a wee bit. Edited June 14, 2013 by copemech 1 Quote Link to comment Share on other sites More sharing options...
shyted Posted June 14, 2013 Report Share Posted June 14, 2013 None taken copemech , your so easy to resist . Quote Link to comment Share on other sites More sharing options...
sting32 Posted June 14, 2013 Report Share Posted June 14, 2013 Hopefully someone checked for loose bolts all over the bike!!!? I have been scared "..less" to then discover tank bolt was not tight. fenders, tripple clamps, even clip holder on the handlebars can "do the harmonic/demonic" rattle. makes sure everything is tight. ALso BEN, if you post new video, hold the clutch in, on my PC that is all I could hear, gg clutch rattle. 1 Quote Link to comment Share on other sites More sharing options...
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