John92 Posted April 16, 2012 Report Share Posted April 16, 2012 Alright lads I'm looking for an idiots guide to a piston change on my 08 KTM SX144. I'm handy enough with some tools but never done it before and want to make sure I don't balls it up. Any advice appreciated. John. Link to comment Share on other sites More sharing options...
Gregorious77 Posted April 16, 2012 Report Share Posted April 16, 2012 make sure you stuff a rag in the bottom end once the barrel is off to avoid dropping any shit in there (including the circlips for the piston. Put piston in barrel before connecting to rod so you know the rings wont get hung up on a port when sliding the barrel back on. Link to comment Share on other sites More sharing options...
fontyyy Posted April 17, 2012 Report Share Posted April 17, 2012 Put piston in barrel before connecting to rod so you know the rings wont get hung up on a port when sliding the barrel back on. Really? I know the piston is bigger and access may be better but that would be totally impossible on a 250 twin. Link to comment Share on other sites More sharing options...
Gregorious77 Posted April 17, 2012 Report Share Posted April 17, 2012 easy on a single! is it a twin then? Just a couple of tips with no research on the actual bike! I assumed it would be a 2T single. Link to comment Share on other sites More sharing options...
Jenny Pryde Posted April 17, 2012 Report Share Posted April 17, 2012 1.When stripping it down, keep all your bits in clearly marked zip-lock bags. 2.Take photographs. 3.Take your time, work methodically, ideally from a workshop manual. You will need to know the order in which to strip her down (fnarrr) and torque settings when you build her back up. 4.Dunno how KTM powervalves work, do some research on this - overhaul will prob be a good idea. 5.ENSURE EVERYTHING IS CLEAN BEFORE YOU START. 6.Find a KTM forum and find out which manufacturer makes the most reliable pistons. 7.Join a KTM forum, in case it all goes horribly wrong. 8. Don't smack the barrel about to get it off. Use something soft faced. 9.Can't think of anything else. 10.It's not that bad. Even I can do it and I'm a mechanical mong. Link to comment Share on other sites More sharing options...
peter187 Posted April 17, 2012 Report Share Posted April 17, 2012 KTM powervalves are simple. They are centrifigally operated. The links below cover them pretty well. http://www.thumpertalk.com/topic/757439-the-200-pv-unravelled/ http://www.thumpertalk.com/topic/928564-200-pv-unravelled-part-deux/ Link to comment Share on other sites More sharing options...
2Smoke Posted April 17, 2012 Report Share Posted April 17, 2012 The r/h radiator has an 8mm headed bolt for bleeding the cooling system. Some KTM's also have a bleed on the cylinder head by the head-frame mounting. Bleed the system many times until both radiators are totally warm when warmed up. Link to comment Share on other sites More sharing options...
paul g Posted April 17, 2012 Report Share Posted April 17, 2012 From when I had a ktm 125 its pretty much standard stuff as mentioned although I would personally fit the piston on the connecting rod first and then drop the barrel on. One thing that springs to mind though is you need to take care to align the power valve mechanism so it drops into place properly. If you dont the powervalve wont open and it will run like a turd. Do you have the ktm workshop manual? they are very good, on a par with Honda manuals and a worthwhile investment. Link to comment Share on other sites More sharing options...
fontyyy Posted April 17, 2012 Report Share Posted April 17, 2012 easy on a single! is it a twin then? Just a couple of tips with no research on the actual bike! I assumed it would be a 2T single. Oh it's a single but the reason it'd be hard on a 250 is not cause the other barrel is in the way, it's cause by the time the rings are inside the skirt the base of the barrel is about 5mm above the piston pin. There's a little bit of a knack to it but getting the ring(s) in is easy, getting the pin circlip in is a lot tougher even without a barrel in the way. Link to comment Share on other sites More sharing options...
Gregorious77 Posted April 17, 2012 Report Share Posted April 17, 2012 Oh it's a single but the reason it'd be hard on a 250 is not cause the other barrel is in the way, it's cause by the time the rings are inside the skirt the base of the barrel is about 5mm above the piston pin. There's a little bit of a knack to it but getting the ring(s) in is easy, getting the pin circlip in is a lot tougher even without a barrel in the way. Fair enough, I have used both methods but have also caught a ring on a port before when the barrel twisted slightly on the way down!! Last time I done a 125 I put the piston in the barrel first. Link to comment Share on other sites More sharing options...
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