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Post by wooden6587 on Sept 16, 2021 17:08:57 GMT
Hi,
I have a PX125E, 2008, 11000 miles. I know a little about engines – which, I know, is dangerous. I have done some very minor basic servicing but usually try to take it to a Vespa dealer for a proper one!
I had a fuel pipe split and just about managed to get it to the Vespa dealer some 15 miles away who replaced the fuel pipe and serviced the scoot.
It may be my imagination but since then, when the fuel gauge goes down to about half, the engine, when it is warm, “dives” (bogs??).It is like putting on the brakes. The engine recovers if the throttle is released, which is a bit embarrassing in traffic. I know that that is a typical fuel starvation issue.
Can the fuel pipe or tank outlet be at fault or is it definitely a carb problem?
I have had the carb to pieces and cleaned the jets with a can of compressed air. Cleaned the fuel filter and air filter and fuel chamber. I was careful enough not to disturb any settings and it has always started and idled well. To be fair, it runs well for a short while then suddenly it “dives”.
Is it possible that the jets aren’t clean enough?
If you think I should try a professional again I may need to know of one closer to me in East Beds.
Any thoughts or recommendations would be appreciated.
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Post by ironsloth on Sept 16, 2021 18:42:21 GMT
I know you said a dealer did it but I would check the carb and see if everything’s tight, and check the length of your fuel pipe. I’d be taking the big metal b*st**d back to the shop… 😤
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Post by alan34 on Sept 17, 2021 8:11:01 GMT
Hello there I had same trouble when I changed my petrol pipe on me 2006 px 125 it started to cut out after a few miles.then would start and run for a few miles found fault straight away I had put a petrol pipe on which was to long and inside bore was to small.bought the proper pipe 2foot long and correct bore no more trouble petrol is gravety fed so must be correct pipe.yours might be to long or may have kink in under the tank good luck let us know how you get on cheers alan.
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Post by wooden6587 on Sept 17, 2021 17:13:28 GMT
Thank you Alan34 -that's reassuring. I will give it a try.
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Post by swm on Sept 18, 2021 19:37:05 GMT
This is what I'd do.
Check that breather in tank cap is clear. Next check your carb and jets are clean . Next take out tank and check fuel pipe for kinks and correct length and size . (600mm long and inside bore diameter 7mm) Check good fuel flow to carb, ( 1 pint per min ish !) If not could be as simple as a knackered petrol tap !
Cheers.
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Post by wooden6587 on Oct 23, 2021 19:27:03 GMT
This is what I'd do. Check that breather in tank cap is clear. Next check your carb and jets are clean . Next take out tank and check fuel pipe for kinks and correct length and size . (600mm long and inside bore diameter 7mm) Check good fuel flow to carb, ( 1 pint per min ish !) If not could be as simple as a knackered petrol tap ! Cheers. Thank you for your suggestions here. I disconnected the fuel pipe and timed the fuel output keeping the end of the pipe level with the carb input pipe. This was 400ml per minute.. Then I removed the tank, checked the pipe diameter and it fits a 7mm drill and a 6mm drill is loose, so the pipe diameter is ok. I could not find any kinks. The length of the pipe was 27 inches so I removed 3 inches. The petrol tap has always been stiff to operate so I gave it some 3-in-1 and it changes much more smoothly. Whilst the tank was in its cradle I checked the pipe again and it still ran petrol at 400ml per minute when the pipe was much lower than the tap. Is this to slow? I have replaced the tank and secured all the fittings. The gauge registers a quarter tank full. Took it for a test drive and it loses power "bogs" almost to the point where it cuts out. So - carb jets next? I will remove the jest and soak them in acetone and blow them through with compressed air. Do te;ll me if you see any problems. |
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Post by citydaz on Oct 24, 2021 19:06:46 GMT
Try fitting a fast flow tap from SIP, or BGM, or any other reputable manufacturer!
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Post by adrian on Oct 24, 2021 20:41:18 GMT
Try fitting a fast flow tap from SIP I found the bgm fast flow better than the sip , went through 2 sip ones tried the bgm and it has lasted much longer |
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Post by wooden6587 on Nov 15, 2021 20:51:26 GMT
Try fitting a fast flow tap from SIP I found the bgm fast flow better than the sip , went through 2 sip ones tried the bgm and it has lasted much longer Hi, Just an update. Before trying a new tap, I will check the carb. The air filter and the casing that the carb and air filter sit in are soaking in petrol. I have removed the carb and will take it apart (not the mixture screw) and give it all a good clean with fresh petrol filter and gaskets and seals.. If that's not my problem I will look at replacing the fuel tap - need a tap removal tool. Many thanks for your contributions. |
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Post by adrian on Nov 15, 2021 21:38:15 GMT
Do you have access to an ultra sonic cleaner ? They great for cleaning the carburetor. If you don't have access to one, there cheap enough 👍 where abouts are you based
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Post by alan34 on Nov 16, 2021 9:43:21 GMT
Hello there. get a tin of carb cleaner it cleans the gum of the jets and inside passageways better than petrol also if you want to take out mixture screw just turn it in and count the turns then write the number down and you can put it back where it was after cleaning let us know how you get on cheers alan.
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Post by wooden6587 on Nov 17, 2021 19:25:49 GMT
Do you have access to an ultra sonic cleaner ? They great for cleaning the carburetor. If you don't have access to one, there cheap enough 👍 where abouts are you based I am based in East Bedfordshire. I have to fix the petrol leak first then try cleaning. I will look into a US cleaner though. Thanks for that. |
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Post by adrian on Nov 17, 2021 21:44:29 GMT
The ultra sonic cleaner was one of the best purchases made for my garage, all my mates bring there carbs around to get them cleaned 👍👍
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gao
2nd Class Ticket
Posts: 32 
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Post by gao on Nov 18, 2021 8:14:10 GMT
Anything under the seat, say a rag, blocking the air flow?
It’s simple but is possible 😀
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Post by adrian on Nov 18, 2021 16:58:57 GMT
Anything under the seat, say a rag, blocking the air flow? It’s simple but is possible 😀 did that with my waterproofs , lesson learnt, haven't stored anything under seat since |
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Post by wooden6587 on Dec 29, 2021 17:43:14 GMT
OK...
Done all the investigating. Removed the carburetor, cleaned it thoroughly, jets with acetone and an air spray. Replaced gaskets. Took it for a short ride and all went well. Parked up last week. The carb is now leaking oil. Can only be the 2 stroke oil. Where would that be coming from? Are there any seals to check ? Where does the oil go to when it comes out of the oil pump?
I will take the lid and air filter off tomorrow and see if I can pinpoint the precise area.
Any help would be appreciated.
Update:
Carburetor seems clear. A little oil appears at the carb/airfilter joint when I removed the air filter. I will keep my eye on it.
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Post by wooden6587 on Feb 11, 2022 15:11:46 GMT
Update again.
Thanks for all the contributions.
Cleaned carb and casing. Stopped petrol leak with a new seal in the fuel filter cap.
Took it back to the Vespa service centre.
Mechanic said he couldn't find an issue until.... wait for it... the needle was the incorrect size - had I changed it? NO.
Can you get different sizes of needle on a standard carb? I tried finding one on line and the dealer said no???
Anyway all is good now.
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