I hope somebody can help here i've run out of ideas.......... its a bit long winded but please have a read !!!
Right i bought an MZ 125 SM (52 plate) which had not been started for over a year and was sold as a none runner due to the owner not been able to get it started however when i collected it it started but cut out after a few seconds so i thought buzzing its something and nothing to get it going properly..............how wrong was i...........
I started by cleaning the carb out literally no screw left untouched i set the air mixture screw to the recommended 2 turns out as i've seen mentioned many time on here but on cleaning it out there was no real debris found.
I refitted the carb and got the bike started but even though it would tick over like a clock it would not rev up it just sounded like it was getting starved of fuel and would cut out so out came the carb again and i set the float as per the owners manual just to see if that was a problem but tbh it wasn't out of adjustment a lot so once again i refitted the carb and nothing had changed it would still not rev up but would tick over perfect.
Sometimes on start up i could here a knocking sound but not always so i drained the oil and found quite a lot of copper filings in the oil and filter almost like glitter so just as a temporary measure i cleaned out the filter and replaced also with fresh oil if say the engine is in need of a rebuild due to knackered shells / bearings i would of thought it would still rev up but the knocking would get louder like with a car engine if its shells or bearings are knackered it would still rev up but would sound like a bag of nails.
Anyway.....
So its all back together now with fresh oil etc once started the knocking is still there now and again but it will still not rev up so i got some of advice off a friend and they said check the timing so i did as told and checked the timing the inlet cam was slightly out also the exhaust but again not massively out so i set it as per the manual also followed a guide on here and set it bang on............
But now it struggles to start and when it does it makes one hell of a racket some serious knocking going on i havent even tried to rev it due to the noises it makes now but tbh i dont think it would rev even if i tried.
I'm coming to the end of my tether with it now i'v tried everything thats been mentioned by friends and from what i can see on here in relation to its issues just to mention also the filler cap on the tank is not blocked also its been run on normal unleaded not super unleaded as i've seen mentioned on here they don't like fuel with ethanol added to it and i've also checked for spark and there is no problem there either.
Can anybody shed any light on this please??
Any advice would be greatly appreciated.
Thanks in advance.
Gaz.
