Hemberg Posted September 26, 2011 Share Posted September 26, 2011 Good day everyone My pap pa 125 broke down a few weeks back, this time it was the piston ring that caused a broken piston and some scratches into the cylinder. Probably my own fault since I should have changed piston ring earlier. but... The opening of the piston ring passes a port on the old piston. When I changed piston the opening of the piston ring is in another position. I don't know if that makes any difference but i sound like a bad place to have the opening of the piston ring in the same place as a port opening, right? Quote Link to comment Share on other sites More sharing options...
weesplat Posted September 27, 2011 Share Posted September 27, 2011 Right !! never never the gap goes past the port. They shouldn't line up either if there is more than one ring. Usually go against the side walls. Sometimes the location pins for the rings have been known to fall out with m/cycle engines allowing the rings to turn . If you give it a tug with some pliers (the one in the old piston) you may find its just wedged in the groove rather than embedded in the piston in the groove. Hope you get it sorted soon Quote Link to comment Share on other sites More sharing options...
Hemberg Posted September 27, 2011 Author Share Posted September 27, 2011 Makes sense not to have the opening towards a port. The motor broke because the open end of the piston ring hit the exhaust port opening and got stuck and broke the piston and cylinder. The original piston that came with the motor had this configuration (location pin at the exhaust port) The one I got to replace it doesn't ( that one came also from pap). The replace piston is a HE piston with graphite coating. So for those that have an early pap pa 125, make sure not to wait too long to change piston ring. Maybe might as well change the piston. Quote Link to comment Share on other sites More sharing options...
garyfreefly Posted September 27, 2011 Share Posted September 27, 2011 wonder if if could be a warranty issue......ie because of a faulty positioned piston ring retention pin.... because as you are well aware there has been (( several )) warranty replacement modifications for the early units Quote Link to comment Share on other sites More sharing options...
Hemberg Posted September 27, 2011 Author Share Posted September 27, 2011 Yeah I know, I'll mail pap the hear what they have to say about it. Pity with all these setbacks, the motor feels well made except for some silly construction errors that pap - with their experience - should have thought of. Quote Link to comment Share on other sites More sharing options...
lukebanks1 Posted October 5, 2011 Share Posted October 5, 2011 The original piston was wrong! As Gary says a definite warranty issue. Quote Link to comment Share on other sites More sharing options...
Hemberg Posted November 19, 2011 Author Share Posted November 19, 2011 Well I probably was wrong, after looking at the piston more carefully the retention pin had probably broken off somehow and the piston ring turned 180 degrees and got caught, anyway pap consider it being a warranty issue so that's good news. They are not sure how it happened but wants me to check the squish so I'm going to do that before I run it again. Quote Link to comment Share on other sites More sharing options...
notch Posted November 20, 2011 Share Posted November 20, 2011 Hemberg, What were pap's instructions for the squish? I tried to get this info before, nut never got an answer. Did you also find out how to set the ignition timing? -N Quote Link to comment Share on other sites More sharing options...
Hemberg Posted November 20, 2011 Author Share Posted November 20, 2011 They gave me a pdf (in spanish) it's too big to include in the message, but mess me and we'll sort that out. there seems to be similar info on youtube as well, how to check it. The technique used is to remove the spark plug and squish solder on the top of the piston and then measure the solder. Quite clever I must say. Haven't got any info about ignition timing. Quote Link to comment Share on other sites More sharing options...
Guest Posted November 20, 2011 Share Posted November 20, 2011 You can attach PDF files to your post SW Quote Link to comment Share on other sites More sharing options...
Hemberg Posted November 20, 2011 Author Share Posted November 20, 2011 I can, but the size is to large it seems, it only accepts to 800 kb, the file is 5.5 mb Quote Link to comment Share on other sites More sharing options...
marko330 Posted November 22, 2011 Share Posted November 22, 2011 silly question but.... i take it you did have the arrow/indicator mark on the top of the piston facing the exhaust port yes ? this is as with ALL two stroke engines cheers marko Quote Link to comment Share on other sites More sharing options...
pete_b Posted November 22, 2011 Share Posted November 22, 2011 silly question but....i take it you did have the arrow/indicator mark on the top of the piston facing the exhaust port yes ? this is as with ALL two stroke engines cheers marko Not all have the arrow on!! Quote Link to comment Share on other sites More sharing options...
marko330 Posted November 23, 2011 Share Posted November 23, 2011 arrow or a dot or a number which ever it will have one on there and it will be to one side if the piston have a look the next time you have a two stroke piston in your hand marko 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.