barfy Posted January 28, 2018 Report Share Posted January 28, 2018 My son's 2016 125 is a little rattlely, smokes slightly (running it at about 90:1) and poor at starting when it's hot (sometimes stalls). I clean the air filter every trial and carburetor every two or three trials because we live down south where it's often muddy. So I was wondering if it was time to change the rings and small end. I'm used to a 4 stroke where anything like that means new valve seals, rings and small end. I was wondering if there is anything else I should to while doing the work, or if it might be something else. Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 29, 2018 Report Share Posted January 29, 2018 Two strokes are meant to smoke a little. I think Sherco recommend 50:1 fuel:oil ratio and no way would I ever run a 125 at 90:1 No way should a well maintained and properly lubricated 2016 trials engine need rebuilding already. Try Castrol A747 at 50:1. If it cures your problems keep using it, if not strip and measure the top end. Before someone posts contradicting this suggestion, I do know that A747 is not really a trials engine oil but it is a very good lubricant and usually quietens top end considerably. 1 Quote Link to comment Share on other sites More sharing options...
copemech Posted January 29, 2018 Report Share Posted January 29, 2018 Does your son ride the bike well? if he does he likely revs it hard at times. I have never seen a new ring fix a piston rattle, an off to Langcourts would likely be needed. Stick with 80 to 1 ratio meself, and away from the Castrol 747, which runs quiet because it gunks up a low revving motor, not designed for it! Quote Link to comment Share on other sites More sharing options...
barfy Posted January 29, 2018 Author Report Share Posted January 29, 2018 Thanks for the advice. I was mainly concerned about the smoking and poor starting when it’s hot. It’s not pouring smoke and when starting occasionally it might need the choke especially if it stalls. Although a bit of a rattle compared to a new engine it’s not that bad. I run it on Putoline TT Pro 2 Stroke oil and settled at 90:1 as opposed to the 80:1 because someone commented that it was a bit smokey and probably had too much 2 stroke oil. They reconnected to run it at 100:1, but I though that was a bit weak. My son rarely nails the engine because the majority of sections around here are tight rather than big. Perhaps I’ll try a hotter plug to see it that improves the hot starting when it’s hot. Quote Link to comment Share on other sites More sharing options...
copemech Posted January 30, 2018 Report Share Posted January 30, 2018 not rattling badly then yes, ring it and go, as a bit or rattle is a non issue. Agree on the EIX plug as well, but you know, they allways need a good thrashing or a drag race or two during a day out, just to get some real heat into the exhaust and get the gunk flowing. mind you it may get real smokey for a bit, but that is a good thing. 1 Quote Link to comment Share on other sites More sharing options...
barfy Posted January 31, 2018 Author Report Share Posted January 31, 2018 Thanks for the advice. I’ve got an EIX plug on order. We’ll see what difference that makes next weekend. Quote Link to comment Share on other sites More sharing options...
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