dane Posted February 26, 2011 Report Share Posted February 26, 2011 Out riding today, the bike seemed to gain a slight noise from the engine, a soft tapping noise, that varied with the engine speed. I believe its the piston, as that wass where the noise was coming from, not from the big end (im hoping its not aswel!) I've stripped the bike apart, yes theres a little play in the piston(at the bottom of the stroke), but i am having trouble getting the 2 nut's off the front of the barrel - i cannot get a spanner or socket to fit against the barrel!! Is there a specific spanner etc to make this easier ? And finally...i know the guy who owned the bike wsa out most weekends, as i am, but how often should a piston / rings approx be lasting ? I am running castrol TTS at 75ml to 5L of Super Unleaded. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
monty_jon Posted February 26, 2011 Report Share Posted February 26, 2011 Out riding today, the bike seemed to gain a slight noise from the engine, a soft tapping noise, that varied with the engine speed. I believe its the piston, as that wass where the noise was coming from, not from the big end (im hoping its not aswel!) I've stripped the bike apart, yes theres a little play in the piston(at the bottom of the stroke), but i am having trouble getting the 2 nut's off the front of the barrel - i cannot get a spanner or socket to fit against the barrel!! Is there a specific spanner etc to make this easier ? And finally...i know the guy who owned the bike wsa out most weekends, as i am, but how often should a piston / rings approx be lasting ? I am running castrol TTS at 75ml to 5L of Super Unleaded. Thanks in advance! I Quote Link to comment Share on other sites More sharing options...
7 Posted February 26, 2011 Report Share Posted February 26, 2011 could be the little end bearing,cheap fix,to get the nuts off the barrel use opended spanner 75ml two stroke is spot on,any more and it wont rev out clean,i use ipon fully synthetic at 50ml with no probs Quote Link to comment Share on other sites More sharing options...
dombush Posted February 26, 2011 Report Share Posted February 26, 2011 I agree that 75ml is adequate, you can run more but..... lets not start that old argument again. Litle end bearings normaly outlast the piston, changing them as a precaution while the engine is apart. However i have had one fail suddenly. Little end wear is normaly audible aunder all engine loads... but is easy to spot as slight vertical play once apart. Piston slap (excessive piston to bore clearance)comes on slowly at first, accelerating as the wear increases. This is normaly noticable under no load situations (tickover). Piston to bore clearance really needs a bore gauge / micrometer to judge properly. As far as getting at the barrel nuts, most of us grind the ring of a ring spanner down to fit. Dom Quote Link to comment Share on other sites More sharing options...
7 Posted February 26, 2011 Report Share Posted February 26, 2011 check out kick start gears you might have chiped one this makes a nasty noise 1 Quote Link to comment Share on other sites More sharing options...
laser1 Posted February 26, 2011 Report Share Posted February 26, 2011 One other simple thing to check is the tank bolt. Usually alittle on the buzzy side, but can sound like alittle like slap and will follow engine rpm. Quote Link to comment Share on other sites More sharing options...
jam Posted February 27, 2011 Report Share Posted February 27, 2011 The manual quotes 2%(50:1), I would be tempted to follow this using unleaded. We do and have had no problems, if the bike has done road work then its been too lean at high temps. Page from the manual:- Recommendations for the reliable operartion of your GAS GAS. Quote Link to comment Share on other sites More sharing options...
gronno Posted February 27, 2011 Report Share Posted February 27, 2011 Handy mixing chart here: http://www.manxyouthtrials.com/two-stroke.pdf Quote Link to comment Share on other sites More sharing options...
dane Posted February 27, 2011 Author Report Share Posted February 27, 2011 Thanks for all the replies. Its now apart and theres some play in the piston so i will replace that and small end bearings. Where's the bet plce to get orignal gasgas piston from (i presume these are best?) and small end bearings plus gaskets? I'm guessing i won't want to know the price??! Thanks in advance, sorry im new to trials and am unfamiliar with part-shops! Quote Link to comment Share on other sites More sharing options...
copemech Posted February 28, 2011 Report Share Posted February 28, 2011 Out riding today, the bike seemed to gain a slight noise from the engine, a soft tapping noise, that varied with the engine speed. I believe its the piston, as that wass where the noise was coming from, not from the big end (im hoping its not aswel!) I've stripped the bike apart, yes theres a little play in the piston(at the bottom of the stroke), but i am having trouble getting the 2 nut's off the front of the barrel - i cannot get a spanner or socket to fit against the barrel!! Is there a specific spanner etc to make this easier ? And finally...i know the guy who owned the bike wsa out most weekends, as i am, but how often should a piston / rings approx be lasting ? I am running castrol TTS at 75ml to 5L of Super Unleaded. Thanks in advance! As you classify this noise as slight, not sure you should be overly concerned about it as these motors do have a fair amount of mechanical noise, as with most 2T motors and untill it was evaluated by an experienced gas gas rider I would not panic. Quote Link to comment Share on other sites More sharing options...
monty_jon Posted February 28, 2011 Report Share Posted February 28, 2011 As you classify this noise as slight, not sure you should be overly concerned about it as these motors do have a fair amount of mechanical noise, as with most 2T motors and untill it was evaluated by an experienced gas gas rider I would not panic. Yes, that Quote Link to comment Share on other sites More sharing options...
bigfoot Posted February 28, 2011 Report Share Posted February 28, 2011 I have experienced a similar noise a couple of times on my gassers and on the first occasion did as you are doing. It made no difference and turned out to just be pinking due to poor carburetion. The second time it was a different bike but I was sure the little end had gone. I spent a good few hours cleaning the carb and setting it up again and the noise disappeared. I hope you haven't wasted a lot of time on this only to find as I did that it's just setup. It was far worse when hot and it was overheating too as it The noise is so convincingly mechanical it Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.