Diablo** Posted May 3, 2010 Share Posted May 3, 2010 hi i have had my bike a little while, had no problems til the thread got knackered on the head then it decided to crack, replaced it with a standard 125 head and piston, now when i try to start it, it will try and try then backfire and try some more but wont start. it was working fine before even though the head was wrong and it had piston slap, the spark is sparking petrol flowing and 2 stroke lubricating, i cant see why it wont start as all i have done is replace the broken head and pistons, please please help if you can as i love this bike and dont wont to blow it up which was on my mind after trying for 8 hours to get it working Link to comment Share on other sites More sharing options...
FZR AL Posted May 3, 2010 Share Posted May 3, 2010 hi i have had my bike a little while, had no problems til the thread got knackered on the head then it decided to crack, replaced it with a standard 125 head and piston, now when i try to start it, it will try and try then backfire and try some more but wont start. it was working fine before even though the head was wrong and it had piston slap, the spark is sparking petrol flowing and 2 stroke lubricating, i cant see why it wont start as all i have done is replace the broken head and pistons, please please help if you can as i love this bike and dont wont to blow it up which was on my mind after trying for 8 hours to get it working what the compression like? Link to comment Share on other sites More sharing options...
Diablo** Posted May 3, 2010 Author Share Posted May 3, 2010 what the compression like? It seems ok, Link to comment Share on other sites More sharing options...
Moderator Cynic Posted May 4, 2010 Moderator Share Posted May 4, 2010 When you say new std parts, were the old ones standard?, or the same spec? Please tell me you have tried a different (known good) plug. Link to comment Share on other sites More sharing options...
Diablo** Posted May 4, 2010 Author Share Posted May 4, 2010 When you say new std parts, were the old ones standard?, or the same spec? Please tell me you have tried a different (known good) plug. hi have tried two plugs, gonna get another one to day as not sure if the two i had were the rite ones, as one came with bike and one came with new head, both sparked ok though. the head i took off had a 65mm bore and the piston wasn't rite it was slapping, i now have standard head which is 56mm bore and piston. would a broken ring cause the problem? Link to comment Share on other sites More sharing options...
FZR AL Posted May 4, 2010 Share Posted May 4, 2010 hi have tried two plugs, gonna get another one to day as not sure if the two i had were the rite ones, as one came with bike and one came with new head, both sparked ok though. the head i took off had a 65mm bore and the piston wasn't rite it was slapping, i now have standard head which is 56mm bore and piston. would a broken ring cause the problem? have you got a broken ring ? thats why i was asking about compression cheers Al Link to comment Share on other sites More sharing options...
Diablo** Posted May 4, 2010 Author Share Posted May 4, 2010 have you got a broken ring ? thats why i was asking about compression cheers Al yeah one of the rings a little bit broke off, just ordered some new rings, would that be the cause? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted May 4, 2010 Moderator Share Posted May 4, 2010 yeah one of the rings a little bit broke off, just ordered some new rings, would that be the cause? Its more likely a carb issue, you have actually dropped from 175 (ish) cc to 125 cc so if the carb was set for the big bore the engine will be rich on an epic scale. Like running on full choke full time. The busted ring won't help mind. Link to comment Share on other sites More sharing options...
Diablo** Posted May 5, 2010 Author Share Posted May 5, 2010 Its more likely a carb issue, you have actually dropped from 175 (ish) cc to 125 cc so if the carb was set for the big bore the engine will be rich on an epic scale. Like running on full choke full time. The busted ring won't help mind. carb is standard not been rejetted normal 125 carb for a teazer Link to comment Share on other sites More sharing options...
FZR AL Posted May 5, 2010 Share Posted May 5, 2010 Im not teaching you to suck eggs but have you got the piston in the right way, arrow pointing to the front wheel, when you get your rings just double check use plenty of 2 stroke around the piston and bore this will help with the seal cheers al Link to comment Share on other sites More sharing options...
Diablo** Posted May 5, 2010 Author Share Posted May 5, 2010 Im not teaching you to suck eggs but have you got the piston in the right way, arrow pointing to the front wheel, when you get your rings just double check use plenty of 2 stroke around the piston and bore this will help with the seal cheers al new rings put on still wont start, i put the old head back on with oversized bore and the bike started, so i think the carb HAS been rejetted for 250 head, have just bought a 125 carb repair kit with new jets and stuff so hopefully when that arrives i can put the 125 head and pistoon back on and she should fire up. ill keep u posted thamks for all your assistance Link to comment Share on other sites More sharing options...
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