pink
1st Class Ticket
Posts: 65
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Post by pink on Jun 22, 2017 11:48:05 GMT
Hi all. I'm hoping someone may be able to give advice. I'm running a 1990 stock PX200. Starting from cold it's fine, but when engine gets hot the bugger won't start e.g after stopping to fill up, for a quick smoke etc. It seems to be an air issue as, whip air filter off and bingo! Put it back on and needs someone to maintain throttle or it cuts out. Once running though it's fine again. Only non standard part is sterling pipe. Carb is 24/24 with 118 main jet and 55/160 starter jet. Air filter heart is drilled out with 2 holes, but not fully. Running rich at moment with wet black plug, but same when running right mix. Plug is NGK B8ES. Even threatening it with a hammer isn't fixing this problem! Any tips would be great fully received. Cheers Pink
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Post by henri on Jun 22, 2017 16:11:15 GMT
a b7es plug ,nxt leaner pilot jet , an ensure ya chokes going fully off is my guess . H
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Post by mijapxman on Jun 22, 2017 16:15:24 GMT
Pink, have you tried another air filter? ( yours may be blocked ) Tried cleaning the pilot and idle jets? Bad hot starting usually points to low compression/worn or nipped rings.Do you have a compression tester?
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Post by pxguru on Jun 22, 2017 16:51:16 GMT
Agree. Could be low compression. Or could just be way too rich on the mixture screw.
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pink
1st Class Ticket
Posts: 65
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Post by pink on Jun 22, 2017 18:30:39 GMT
Cheers guys. Engine was recently rebuilt with new piston & rings fitted along with various other parts. Tried a 'sport' filter, but do have a standard spare which I haven't tried. Cleaned carb & jets with carb cleaner. Haven't got a compression tester but may well invest in one. Any idea what number a leaner jet would be? I'm guessing it's pilot needs changing. Would it be worth drilling the entire heart out? Cheers again Pink
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Post by mijapxman on Jun 23, 2017 4:22:41 GMT
pink, you maybe have a restricted air filter with the inner walls, maybe have a look at mista FreakMoped videos on YouTube, the one called " VESPA PX THROTTLED si AIR FILTER " and the one called " VESPA Si24 Warm Start/ Flooded engine issue & the solutions " you may find them useful. Sorry can't get the links to paste.😳 Good luck. Jim☺
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Gothlife
1st Class Ticket
Rookie on the learning curve.
Posts: 84
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Post by Gothlife on Jun 23, 2017 7:04:24 GMT
Morning.
I'm having the same issue with my PX125. In this hot weather it's even started to flood just sitting at the lights which is causing it to bog as I pull away which isn't the safest! Will watch the above videos and hopefully get shot of the issue.
Any progress please let us know.
Kriss.
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pink
1st Class Ticket
Posts: 65
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Post by pink on Jun 27, 2017 11:05:32 GMT
Morning guys. Due to work I've not managed to check all of your suggestions yer. Just checked compression, 100 psi which seems a touch low to me. I'm thinking between 110 and 130 Mark. Am I right? Cheers Pink
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Post by pxguru on Jun 27, 2017 14:55:43 GMT
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pink
1st Class Ticket
Posts: 65
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Post by pink on Jun 27, 2017 15:41:12 GMT
Cheers. I'll fetch barrel off when get chance. Bore should be fine as only recent rebuild, so may need oversize rings.
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Post by bryno on Jun 27, 2017 19:05:22 GMT
Sounds to me like it's flooding when stopped, starting only with the filter off means it's likely flooded and needs the extra air to correct the mix.
Cleaned or changed the float needle valve?
Compression poor would also cause poor starting but I'd start with checking if it's flooding before taking the head off personally.
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Post by mijapxman on Jun 28, 2017 15:45:39 GMT
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pink
1st Class Ticket
Posts: 65
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Post by pink on Jul 2, 2017 16:44:17 GMT
Head off! Top left stud blooded threaded in casing! Just tried some z-21 thread lock. Failing that it's the helicoil option. Stripped carb previously and needle ok, but seeing as barrel off ill try it all. Filter hadn't got the wall. Pink
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