Leftyno1 Posted November 27, 2015 Share Posted November 27, 2015 So this is why compression is Low 90 psi, interesting how wear is on exhaust port side, Piston has welded to the rings anybody else had this happen, Obviosly going for rebore and piston kit etc.6500miles apparently that is about the time for first rebore according to Local Yam centre Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 27, 2015 Moderator Share Posted November 27, 2015 yeah although the pic is only a thumbnail it does look a bit ragged, 90psi though, not great but not the worst either Link to comment Share on other sites More sharing options...
Moderator Cynic Posted November 27, 2015 Moderator Share Posted November 27, 2015 6500mls, yammy dealer is talking crap. More like 14k. My TDR did that b4 it blew.I have heard of 350's doing 20k before trouble. Used responsibly and with quality oils. Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 28, 2015 Author Share Posted November 28, 2015 Well this little DT has not been looked after very well by previous owner,so hardly suprising, just hoping after rebuild that she will start as that was original problem, classic case of no PPM ( planed preventive maintenance ) being carried out .Will be a good bike in the end but bought a pup as they say oh well deep sigh. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted November 28, 2015 Moderator Share Posted November 28, 2015 (edited) Been there, everybody has bought a lemon at least once. its a common enough happening for 2 strokes and looks pretty much like yours, ignoring the vertical lines you can see the actual damage on the piston wall at approximately 4 equidistant spots on the piston..Look here for a deeper explanation... http://www.off-road.com/dirtbike/tech/dirt-bike-tech-twostroke-seizure-52428.html Edited November 28, 2015 by Cynic Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 28, 2015 Author Share Posted November 28, 2015 A good link Cynic thanks, I am wondering if the wear took place on the exhaust port side of piston because the power valve was not working when I got it, it was in the closed position permanently I am thinking this could have caused the overheating of the piston in that area as the exhaust gases could not get away at higher revs like they should. Link to comment Share on other sites More sharing options...
Variomatic Posted November 30, 2015 Share Posted November 30, 2015 6500mls, yammy dealer is talking crap. More like 14k. My TDR did that b4 it blew. I have heard of 350's doing 20k before trouble. Used responsibly and with quality oils. Agreed, My uncle Rob had a 350LC YPVS that had done over 42k, ragged to the limit constantly and never missed a beat with the original, 2 strokes are stronger than people give them credit for. Although it did eat itself alive at the end of its life. 14 seems close to the truth. I think a rebore wouldn't go a'miss on that barrel Link to comment Share on other sites More sharing options...
Leftyno1 Posted November 30, 2015 Author Share Posted November 30, 2015 yep re-bore and new piston etc definitely on the to do list. Link to comment Share on other sites More sharing options...
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