November 11, 20187 yr Hi guys, I am new to bikes and have run into a problem! I purchased a second hand Gas Gas 125 pro 2003, evrything was good with the bike although there was a small issue with the clutch, i bleed the system, no real change so put it down to warped plates. Rode the bike this morning, no problems, went out again this afternoon, bike started fine, started riding down the road then the 2 strike sound suddenly got very loud! Now the bike won't start! Any ideas?? Thanks in advance for any help
November 11, 20187 yr has the bike been stood for a while ? this can cause all sorts of issues ,as for noise look at the exhaust but will run with it blowing . look for a spark at plug and have a look at carburettor they can get a bit messed up if left standing for a long time as little as a month in some cases
November 11, 20187 yr Author I don't think the bike has been left for long? I have ridden it several times and not had an issue just this time round?
November 11, 20187 yr Author Just spoken to my son, he said that he put the wrong fuel in, he just put in straight 98 unleaded that was meant for the ride on lawnmower! Is that the issue???
November 11, 20187 yr No oil! Yikes, the piston probably siezed. Pull the front exhaust pipe to get a peek at the piston and rings.
November 11, 20187 yr Author What am i looking for? I can crank it, but making much more of a popping noise if that makes sense!?!
November 12, 20187 yr The piston melted o to the rings. If you are lucky, just piston and rings. If you are unlucky you took out the rod.
November 12, 20187 yr Author So, i have managed to remove the head, no discernable markings inside the bore, and piston seems ok and rings are intact but everything seemed to have quite a coating of oil on it? What does that mean? Rings and piston have gone? (Sorry a bit new to this!) The con rod seems ok aswell! Phew! Well i think it's ok! It's not in pieces at least!
November 13, 20187 yr You have the head or the cylinder off? Usually if it seized the rings would be stuck to the piston. A picture would be good or have someone look at it.
November 13, 20187 yr Looks like several things happened. It got hot and took out the orings on the head. Is that just carbon on the piston or metal flakes. The rings look barely stuck and I would be surprised if there is any chrome left in the bore.
November 13, 20187 yr Author It feels like grease/carbon. What's the next step? New piston and rings?
November 13, 20187 yr 4 hours ago, Alexdukes said: It feels like grease/carbon. It is a Teflon [non stick] coated piston .....the fact it is still intact shows that it was a nearly new piston.
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